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Purpose: Orthodontic treatment involving premolar extractions might improve the angulation of lower third molars, which are the teeth most often impacted. This study analyzes the impact of first/second lower premolar extraction during orthodontic therapy on the angulation of mandibular third molars., Methods: A total of 120 patients treated non-extraction (n = 40), with extraction of first (n = 40), or second lower premolars (n = 40) were included. The mesiodistal angulation of lower third molars relative to the adjacent tooth and their developmental stage were evaluated from posttreatment orthopantomograms. Between-group differences were statistically evaluated at a significance level of 0.05., Results: The orthopantomograms of 120 patients (51% female) with a median age of 15.2 years at the time of debonding were evaluated after a mean treatment duration time of 2.9 years. No difference (P > 0.05) was seen between the average angulation of the lower third molars of the right (mean = 24.4°, standard deviation [SD] 13.6°) and the left side (mean = 23.6°, SD 14.1°). No differences in the angulation of the lower third molar were found between the non-extraction and extraction groups for the right (P = 0.44) or the left side (P = 0.22). Likewise, no differences were found when comparing the first and second premolars for the right (P = 0.26) or the left side (P = 0.10). Premolar extraction was associated with an advanced root development stage of the right third molar (odds ratio 7.1; 95% confidence interval 1.1-48.1; P = 0.04), with no differences between extraction of the first or second premolar (P = 0.10)., Conclusion: Orthodontic treatment involving premolars extractions might be associated with a small acceleration in root development, but not with the angulation, of lower third molars., (© 2023. The Author(s).)

Introduction: This study aimed to investigate the expression of root angulation in canine, premolar, and first molar teeth adjacent to first and second premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners (Align Technology, Santa Clara, Calif)., Methods: Adult patients (aged ≥18 years) with at least 1 first and/or second premolar extraction in the maxilla and satisfying strict selection criteria were evaluated. Digital models representing pretreatment, predicted, and posttreatment were obtained from Align Technology's digital interface, ClinCheck. The Geomagic Control X (version 2017.0.3; 3D systems, Rock Hill, NC) software facility was used to determine and compare the root angulation of adjacent canine, premolar, and first molar teeth at different time points., Results: The predicted angulation of teeth was significantly different (P <0.02) than that achieved in most patients. When adjacent teeth roots were planned to tip away from the extraction site, there was an overexpression of the movement. When teeth roots were planned to tip into the extraction site, underexpression occurred, and movement was in the opposite direction in some instances. There was no difference in root angulation outcomes according to the prescribed number of aligners, 1- or 2-week wear protocols, and sex (P >0.05). Attachments were influential in controlling angulation in first-premolar extractions (P = 0.05), but optimized attachments were not any more effective than conventional attachments (P >0.05)., Conclusions: The achieved root angulation in teeth adjacent to premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners differed significantly from that predicted. Attachments play a minor role in the predictability of root angulation outcomes., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the dimensional changes in the alveolar crest after buccal overbuilding was performed prior to tooth extraction in a dog model., Materials and Methods: At the test sites, alveolar crest overbuilding was performed on the buccal aspect of the distal root of the third premolar using xenograft covered with a collagen membrane. No treatment was applied at the control sites. After 3 months, the distal roots of both third premolars were extracted and implants were immediately placed into the alveolus, allowing nonsubmerged healing. After 3 months, biopsy samples were collected., Results: Upon histologic analysis, no statistically significant differences in hard tissue dimensions were found. The buccal bone plate at the test sites presented a tendency for higher resorption compared to the control sites. However, if the contribution of the residue of biomaterial is considered, a higher volumetric gain was registered at the test than at the control sites., Conclusions: The buccal overbuilding performed prior to tooth extraction did not contribute to the preservation of the alveolar crest dimensions after extraction. This could be due to failure to incorporate the graft into the newly formed bone.

Background: The aim of the investigation was to evaluate if the inclination of the lower anterior teeth can be controlled reliably after lower premolar extraction for Class III camouflage treatment with completely customized lingual appliances (CCLAs). Treatment outcome was tested against the null hypothesis that lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will lead to further compensation by retroclining mandibular incisors during CCLA treatment., Methods: This retrospective study included 25 patients (f/m 12/13; mean age 20.7 years, SD 9.5 years) with uni- or bilateral Class III molar relationship and a Wits value of ≤ -2 mm. In all consecutively debonded patients, lower premolars were extracted to correct the sagittal relationship with a non-surgical camouflage approach. Lateral head films prior to (T1) and at the end of lingual orthodontic treatment (T2) were used to evaluate skeletal and dentoalveolar effects. A paired t-test with alpha = 5% was used to define differences between the endpoints. The linear correlation between the inclination of the mandibular incisors at T1 and the achieved correction was measured with the Pearson correlation coefficient (PCC). A Schuirmann's TOST equivalence test was used to check if the final lower incisor inclination was within the defined norms., Results: The null hypothesis was rejected as the mean lower incisor inclination was improved by 1.8° despite lower premolar extractions (T1: 86.8°/ T2: 88.6°). There was a strong correlation (-0.75) between the lower incisor inclination at T1 and the achieved correction indicating a controlled correction towards the norm regardless of the initial incisor position. At T2, the interincisal angle as well as the lower incisor inclination were within the norm., Conclusion: Lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will not lead to undesired retroclining of mandibular incisors during CCLA treatment even in severe cases., (© 2024. The Author(s).)

Introduction: Third molars (M3) remaining impacted in Class II malocclusion characterised with sagittal mandibular deficiency is a high probability. The null hypothesis of this study is that mesioangular M3s changes position through the eruption way in Class II malocclusion treatment requiring moderate anchorage with four first premolars extraction. The aim of this study is to reconsider the decision to surgically extract impacted third molars in four premolars extraction treatment of Class II malocclusion., Material and Methods: The materials consisted of the pre-treatment and post-treatment lateral cephalograms and orthopantomographs of 30 individuals with skeletal and dental Class II malocclusion with a mean chronological age of 13.48 years, who were treated by the same clinician (H.G.) with four first premolar extractions via the straight wire technique at the Ankara University Faculty of Dentistry Department of Orthodontics, Ankara, Turkey. The sagittal position of the upper and lower incisors and molars, M3 position and M3 space were evaluated with the paired-t test; the relationship between the sagittal position of the upper and lower incisors and molars and the change in M3 position were evaluated with correlation analysis.  Results: The study found the retroclination and mesial movement of the upper incisors and molars, and an increase in the M3 space by the fixed orthodontic treatment. An insignificant steepening of both the upper right M3 position and the lower right M3 position was found. A statistically significant increase in the lower right and left side M3 spaces was found. Positive correlations between lower right M3 angulation and the sagittal position of the lower incisors and first molars were found., Conclusion: Improvement in the mesioangulation of the M3s and an increase in the M3 space were achieved in this study. Based on the findings, it is useful to review the decision for prophylactic surgical extraction of the M3s before orthodontic treatment in such cases, taking into account the risks of postoperative complications.

Background: This study compared the progression of experimental peri-implantitis between alveolar ridge preservation (ARP) and spontaneous healing (SH) sites in infected (IT) and noninfected tooth (NIT)., Methods: Bilateral mandibular third or fourth premolars of six beagle dogs were randomly assigned to IT and NIT groups. Before extraction, chronic dehiscence defects were created at the mesial root of mid-buccal area in IT group. Four weeks later, the mesial roots of the third and fourth premolars were extracted in all groups.ARP procedure was randomly conducted on one side of the extraction sockets using collagenated bovine bone substitutes and resorbable collagen membrane, and contralateral side was allowded spontaneous healing. After 12 weeks of healing, bone-level implants (ϕ 3.6 × 8.0 mm) were placed at the extraction sockets. Three months of ligature induced peri-implantitis and three months of spontaneous progression were allowed, with radiographs taken at each phase. Biopsies were retrieved at the implant site for histomorphometric, immunohistochemical, and polarized light-microscopic analyses., Results: Radiography demonstrated that the changes in the marginal bone level during the spontaneous progression period showed no significant differences between ARP and SH sites. Only small and/or nonsignificant differences in the progression of peri-implantitis were observed between ARP and SH sites in histomorphometric, immunohistochemical, and polarized light microscopic analyses. Additionally, the IT and NIT groups exhibited similar outcomes for most parameters., Conclusion: ARP with xenogenic bone substitutes might provide similarly robust results as SH sites regarding the progression of experimental peri-implantitis, irrespective of the infected or noninfected nature of the site before tooth extraction., (© 2024 The Authors. Journal of Periodontology published by Wiley Periodicals LLC on behalf of American Academy of Periodontology.)

The emergence of digital surgical guide templates in alveolar surgery has rapidly increased in the past decade, coinciding with the advancements in 3D printing technology. In contrast to conventional freehand procedures, the utilization of digital templates serves as a 'bridge' that facilitates the extraction of impacted teeth with expedited and accurate intraoperative localization, resulting in a notable reduction in surgical duration, minimized trauma, and lowered risk. However, there is significant scope for enhancements in surgical techniques and refinement of surgical guide templates. The purpose of our study was to employ an innovative surgical guide template founded on computer-aided design for the purpose of executing flapless extraction of deeply impacted teeth and investigating a surgical approach that is more effective, secure, and less invasive., Competing Interests: Declaration of Competing Interest The authors declare there is no conflict of interests., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Objectives: This study aims to compare the achieved and predicted root movements in adults after four first-premolar extractions and Invisalign treatment., Materials and Methods: Thirty-three consecutive adults (22 Class I, 9 Cusp-to-cusp Class II and 2 Cusp-to-cusp Class III) from a single clinical division who completed the first series of aligners after premolar extractions were included in this retrospective study. A pretreatment cone-beam computed tomography model was registered onto the pretreatment surface-scanned dental model (SSDM) to locate the pretreatment root apices of the whole dentition. These were copied and transferred to the predicted and achieved post-treatment SSDMs to acquire the locations of the predicted and achieved post-treatment root apices. The differences between predicted and achieved root movements (DPARMs) were tested using the paired t-test or Wilcoxon signed rank test., Results: In the anteroposterior direction, posterior root movements of maxillary and mandibular anterior teeth were poorly achieved (3.24-5.74 mm DPARMs, p < .05). In the vertical direction, roots of maxillary anterior teeth achieved greater intrusion (0.70-0.93 mm DPARMs, p < .05), while those of mandibular incisors achieved less intrusion (0.57-0.65 mm DPARMs, p < .05) than predicted. In the mediolateral direction, lateral incisor roots did not move distally (-0.65 to -0.96 mm DPARMs, p < .05), while those of canines did not move buccally, compared with the prediction (-0.75 mm DPARMs, p < .05)., Conclusions: In the four first-premolar extraction treatments with Invisalign, root movements were not achieved as predicted, particularly for anterior teeth in the anteroposterior direction., (© 2024 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Background: Piezocision is a minimally invasive surgical method aiming to accelerate tooth movement. However, its effect was found to be transient, appertaining to the regional acceleratory phenomenon (RAP). Hence, the aim of the study was to evaluate the effect of single and multiple piezocisions on the rate of orthodontic tooth movement (OTM). Moreover, the impact of both protocols on canine tipping and orthodontically induced inflammatory root resorption (OIIRR) has been assessed., Methods: Thirty indicated patients for the therapeutic extraction of maxillary first premolars were enlisted in this split-mouth study, and they were randomly split into two equal groups, each including 15 subjects. In the Single Application Group (SAG), one side of the maxillary arch arbitrarily received a single piezocision before the onset of canine retraction, whereas in the Multiple Application Group (MAG), piezocisions were randomly performed on one side, three times on a monthly basis, over the 12-week study period. The contralateral sides of both groups served as the controls. Canine retraction was carried out bilaterally using nickel-titanium closed-coil springs, delivering 150 g of force, and the rate of tooth movement, as well as canine tipping were evaluated on a monthly basis, over a 3-month period. Cone-bean computed tomography scans were also conducted pre- and post- canine retraction, and OIIRR was assessed using Malmgren Index., Results: The reported outcomes revealed a significant increase in the amount of canine retraction, canine tipping, as well as root resorption scores on the experimental sides in both groups SAG and MAG post-retraction (p < 0.001). However, upon comparing the experimental sides in both groups, non-significant differences have been observed between them regarding all the assessed outcomes (p > 0.05)., Conclusions: Single and multiple piezocisions effectively accelerate OTM in comparison to conventional orthodontic treatment, with relative outcomes reported by both intervention frequencies. Accordingly, single piezocision is recommended as an adjunct to OTM. Furthermore, significant tooth tipping as well as a significantly higher root resorption risk accompanies both single and multiple piezocision applications in conjunction with OTM., Name of the Registry: Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05782088 DATE OF REGISTRATION: 23/03/2023 "Retrospectively registered". URL: https://clinicaltrials.gov/ct2/show/NCT05782088., (© 2024. The Author(s).)

The purpose of this study was to evaluate the efficacy of different techniques in removing calcium silicate intracanal medicament (Bio-C Temp). Forty human single-canaled premolars were randomly distributed into five groups (n = 8). All root canals were instrumented, then filled with Bio-C Temp. Following 1-week incubation, the intra-canal medicament was removed using one of five techniques according to tooth group: conventional syringe irrigation, Endo Activator, passive ultrasonic irrigation (PUI), ProTaper Universal F3 and XP-endo Finisher (XPF). Micro-CT scanning was performed before and after removal of Bio-C Temp. All techniques significantly reduced the volume of Bio-C Temp (p < 0.001) without reaching complete elimination. The percentage of Bio-C Temp removed was significantly higher in the XPF group (98.2%) compared to conventional syringe irrigation (70.6%), the Endo Activator (75.7%), and the ProTaper Universal (76.6%). There was no significant difference between the XPF and PUI (95.1%) groups. None of the removal techniques were able to completely remove Bio-C Temp from the root canal. However, XPF was the most effective method, but was not statistically significant when compared to PUI. Clinical Relevance: This study demonstrated that both XPF and PUI outperform conventional irrigation in removing Bio-C Temp intracanal medicament., (© 2024. The Author(s).)

The aim of the study was to measure the degree of dentine surface roughness caused by five distinct lasers used to treat dentine hypersensitivity, as well as to evaluate the subsequent bacterial colonization on these irradiated surfaces. Sixty human maxillary premolar teeth without caries or restoration which were extracted for periodontal reasons were used in this study. Five different types of lasers were applied to the root dentin surface. Tested samples were divided into six groups of 10 samples each; control, diode (810 nm), diode (980 nm), Nd: YAG, Er: YAG, and Er, Cr: YSGG laser groups. The arithmetic mean of the surface roughness values (Ra) and the average roughness over a measurement area (Sa) were measured pre- and post-application using any of the laser types. Swab samples were then collected from the dentin surface. Following a 24-hour incubation period at 37 °C, the colony forming units were counted using a stereoscope. The results demonstrated a statistically significant difference in the surface roughness values pre- and post-application (Ra and Sa, respectively) in the Er, Cr: YSGG laser group (p = 0.037,p = 0.007). No significant difference was observed in the other groups (p > 0.05). There was no statistically significant difference in the number of bacterial colonies observed between the test and control groups. Diode and Nd: YAG lasers showed either a decrease or no change in surface roughness; however, the hard tissue lasers (Er: YAG, Er, Cr: YSGG) showed an increase. The Er: YAG and Nd: YAG laser groups exhibited decreased bacterial adhesion compared to the other groups., (© 2024. The Author(s).)

Objectives: To evaluate the impact of changes in upper incisor inclination and position on the alteration of the nasolabial angle (NLA) in a series of cases involving the extraction of four first premolars., Materials and Methods: The study included 41 patients who underwent orthodontic treatment with premolar extractions. The patients were divided into two groups based on their pretreatment NLA values: Group 1 (NLA ≤ 100°) and Group 2 (NLA > 100°). Measurements of NLA, U1.NA and U1-NA were obtained before and after treatment and U1-Ls pretreatment measure was registered. Statistical analyses were performed to compare the differences in NLA, U1.NA and U1-NA between the two groups and to evaluate the influence of these variables added to U1-Ls (T1) on NLA changes., Results: The results showed that Group 1 exhibited significant changes in NLA, while Group 2 did not. However, both groups showed significant changes in U1.NA and U1-NA. In Group 1, 80% of the individuals presented an increase in NLA and 20% no changes. In Group 2, 10% presented a decrease, 57% no changes and 33% an increase in NLA values. Multiple linear regression analysis indicated that the group factor had a statistically significant influence on NLA variation. Additionally, in Group 2, a negative correlation was observed between changes in U1.NA and NLA., Conclusions: The findings suggest that individuals with higher pretreatment NLA values tend to maintain their NLA values even after the correction of upper incisor inclination., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction: The objective of this study was to identify the soft-tissue profile changes and the potential pretreatment cephalometric parameters that clinicians could use to predict the lip response after premolar extraction treatment in adult patients., Methods: Pretreatment and posttreatment lateral cephalograms of 75 white patients treated with premolar extractions were analyzed. The following initial cephalometric measurements were recorded: upper and lower lip to E-plane, vermilion thickness, lip length, maxillary and mandibular incisor inclination, and mentolabial and nasolabial angle. Pretreatment and posttreatment radiographs were superimposed using the Björk structural method to record lip retraction and incisor/lip retraction ratio. Pearson correlation and Kruskal-Wallis tests were used to compare lip retraction and incisor/lip retraction ratio with the cephalometric variables. The sample was divided according to different extraction patterns., Results: The mean upper and lower lip retraction values were 1.4 mm and 1.7 mm, respectively. Vermilion thickness showed a negative and statistically significant correlation (P <0.05) with lip retraction and incisor/lip retraction ratio. In addition, the mean incisor/lip retraction ratio was 61% and 98% for the upper and lower thin lip, respectively, whereas the mean incisor/lip retraction ratio was 17% and 44% for the upper and lower thick lip, respectively. The comparison among extraction patterns did not highlight any noticeable difference., Conclusions: The choice of a specific extraction pattern did not impact lip response. The vermilion thickness was the key factor influencing lip retraction: an increase in this parameter was related to a decrease in lip retraction and vice versa., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objective: This randomized controlled clinical trial aimed to evaluate the clinical performance of composite resin restorations placed after selective caries removal to soft dentin (SCRSD) or stepwise excavation (SW) over an 18-month period., Methods: Inclusion criteria were patients with permanent molars and/or premolars presenting deep caries lesions (≥50 % of the dentin thickness). Teeth were submitted to SCRSD (n = 76) or SW (n = 76). Evaluations were performed based on FDI (World Dental Federation) criterion. Survival analysis was performed to estimate the survival of restorations and its association with clinical variables and socio-demographic characteristics (adjusted Weibull regression model). The study was registered on Registro Brasileiro de Ensaios Clínicos (ReBEC 65ntbc)., Results: The follow-up period ranged from 6 to 18 months (mean ± SD 16.3 ± 3.4 months). Patients' ages ranged from 9 to 55 years (mean ± SD 29 ± 10.5 years). A total of 135 teeth (SCRSD = 72; SW = 63) from 101 patients were evaluated. There were 4 failures in the SCRSD group (2 loss of restoration in need of replacement and 2 marginal fractures in need of repair) and 2 in the SW group (fracture in need of repair). The association between explanatory variables and restoration failure showed similar success rates for SW (99.4 %) and SCRSD (97.9 %) (p = 0.16). Patients presenting gingivitis (≥20 % of sites with gingival bleeding) had 8.50 times more risk for failure than those with <20 % of bleeding sites (p = 0.03)., Conclusion: This study showed that placing a composite resin restoration over soft dentin (after SCRSD) did not affect its clinical performance after 18 months., Clinical Significance: SCRSD is a feasible treatment option for the management of deep caries lesions in permanent teeth as it preserves tooth vitality and tooth structure without compromising restoration longevity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Extraction vs. non-extraction is a crucial decision in orthodontic therapy., Objective: The aim of the present study was to investigate the changes in the dental arch width and buccal corridor after orthodontic treatment using extraction and non-extraction therapy with Damon self-ligating system., Material and Methods: This retrospective study consisted of 35 patients (20 female and 15 male patients with median age of 12.5 years), treated by extracting 4 or 2 premolars, and 37 patients (16 female and 21 male patients with the median age of 12.8 years), treated without premolar extraction. Both groups were treated with Damon self-ligating system. Plaster models before (T0) and after (T1) treatment were measured, and the arch width values were determined at the level of the first molars, second premolars, canines and palatal rugae. Buccal corridor width was measured using the extraoral images at T0 and T1. Paired t-test was used for the analysis of the normally distributed data, and Wilcoxon Mann-Whitney U test was used for the data with non-normal distribution. Values of p<0.05 were set as statistically significant., Results: The upper intercanine width increased significantly in both groups (p<0.01). In the non-extraction group, the arch width increased significantly in the maxillary second premolar and first molar region (p<0.01) as well as in the region of the canines (p=0.04), second premolars (p=0.01) and first molars (p<0.01) of the mandible. The buccal corridor decreased significantly in the non-extraction group (p<0.01)., Conclusion: Premolar extraction in combination with Damon self-ligating system did not lead to reduction of the dental arch width in the maxilla, nor did it increase the size of the buccal corridors.

Introduction: The extraction of second premolars and associated changes in the volume of the airway have not been previously explored. This retrospective study aimed to compare the volumetric changes of the airway preorthodontic and postorthodontic treatment in relevant extraction and control samples and to identify variables that may influence the outcome., Methods: Cone-beam computed radiography scans of 54 patients with second premolar extraction and 59 nonextraction patients treated in a private orthodontic practice were matched for crowding. The average age for both samples was 15 years. The images were individually landmarked and measured by applying volumetric, linear, and angular parameters. The results were analyzed using repeated measures, such as variance analysis, correlation testing, and regression statistical analyses., Results: There was a statistically significant increase in the airway volume for both groups (P <0.05). The difference in increase between the groups was not statistically significant. Seven variables demonstrated a collectively significant effect on changes to airway volume (F[7,112] = 38.48; P <0.001; r 2  = 0.701), with 70% of the variation predicted by the variables. Multiple regression analyses indicated that changes to the area of minimum constriction (B = 32.45; t = 11.95; P <0.001) and changes to airway length (B = 94.75; t = 7.79; P <0.001) had a statistically significant effect on airway volume., Conclusions: The volume of the airway increased in both the extraction and nonextraction samples. The biggest contributors to the increase were an increase in airway length and an increase in the area of minimum constriction, which likely occurred as a result of natural growth., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Aim: This case series was to describe the use of surgical extrusion for three different cases as a technique to re-establish the biological width in patients with insufficient crown height., Background: Surgical extrusion serves as an important means to reestablishing a proper biological width. Such method provides an excellent alternative for the restoration of teeth with insufficient ferrule and ensuring a suitable dental restoration., Cases Descriptions: This case series describes the management of three different cases with compromised teeth #25, #35, and #44, respectively. The approach involved the surgical extrusion of the compromised sites from subgingival to supragingival and the splinting of the teeth using a semi-rigid splint. A successful prognosis was observed on follow-up visits., Conclusion: This technique is a good alternative for general practitioners because of its easy implementation and time efficiency. In addition, the method requires less equipment and provides for adequate space for the re-establishment of biological width., Clinical Significance: Such technique can re-establish a healthy biological width, the existing occlusion can be maintained without alterations, and it demonstrated the suitability of surgical extrusion technique in such clinical situations. Case selection is equally important. Cases with single-rooted teeth with fractures or caries in proximity to the marginal bone level without vertical root fractures generally provide positive outcomes on providing this treatment. How to cite this article: Boreak N, Al Moaleem MM, Zain AA, et al. Surgical Extrusion of Three Premolars to Re-establish the Biological Width: Case Series. J Contemp Dent Pract 2024;25(6):593-598.

Introduction: This study aimed to assess the smile attractiveness in patients treated with or without 4 premolar extractions at a 36-year follow-up., Methods: The sample comprised 52 patients with Class I and II malocclusion divided into 2 groups. Group 1 consisted of 15 patients treated without extractions (10 females and 5 males), with a mean pretreatment, posttreatment, and long-term posttreatment (T3) age of 13.2, 15.1, and 49.8 years, respectively. The mean treatment time was 1.9 years, and the mean long-term follow-up period was 34.7 years. Group 2 consisted of 37 patients (25 females and 12 males) treated with 4 premolar extractions, with a mean pretreatment, posttreatment, and long-term posttreatment age of 13.3, 15.7, and 53.6 years, respectively. The mean treatment time was 2.3 years, and the mean long-term follow-up period was 37.9 years. The mean retention time was 2 years for both groups. Frontal smiling photographs were obtained at long-term follow-up. Smile attractiveness was evaluated in an online questionnaire in which the evaluator could rate the smiling photographs with a 10-point scale. The randomly selected evaluator sample consisted of 62 laypeople, 33 dentists, and 89 orthodontists. Independent t tests, 1-way analysis of variance, and Tukey tests were used for intergroup comparisons at P <0.05., Results: The smile attractiveness on the long term was similar in the groups treated with 4 premolar extractions (4.70 ± 1.35) or without extractions (4.51 ± 1.46). Women and orthodontists were more critical in assessing smile attractiveness than men, dentists, and laypeople., Conclusions: After long-term posttreatment, the smile attractiveness was similar in patients treated with 4 premolar extractions or without extractions., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Introduction The purpose of this randomized controlled canine experimental study was to evaluate peri‑implant hard and soft tissue healing around implants with silver coating. Methods All mandibular premolars and molars of five male beagle dogs were extracted. 25 test and 25 control implants were randomly installed and connected with the healing abutments. After 2 and 4 month healing period, implants with soft and hard tissues were obtained for histologic and histomorphometric analysis. Results In mesio-distal sections, supracrestal tissue attachment dimensions were 4.03±0.48 mm and 4.25±0.66 mm for test and 4.34±0.6 mm and 5.21±0.72 mm for control implants at 2 and 4 month healing time. The respective crestal bone loss values were 1.10±0.69 mm and 0.74±0.67 mm for test and 1.13±0.48 mm and 1.49±0.65 mm for control implants. The differences were statistically significant only in the 4-month healing period. In buccolingual sections, supracrestal tissue attachment height at 2 and 4 month healing periods were 4.09±0.64 mm and 4.5±0.8 mm for test implants and 4.17±0.76 mm and 4.48±0.76 mm for control implants. The respective mean values for crestal bone loss were 1.31±0.6 mm and 1.02±0.58 mm for test implants, and 1.28±0.61 mm and 1.29±0.69 mm for control implants. No statistical significant differences were recorded, apart from the height of connective tissue at the 2 month healing group. No significant difference in terms of BIC between implants or healing periods was recorded. Conclusions The Ag implant coating resulted in smaller supracrestal tissue attachment dimensions and less bone loss. Within the limits of a canine study, prevention of crestal bone loss along with the effectiveness of Ag antimicrobial properties in dental implantology is demonstrated., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financialinterestsor personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

The patient presented in this case report is a 10-year-old boy with hyperdivergent skeletal Class II associated with familial genetic agenesis of the second premolars. The treatment plan chosen was to close the spaces of agenesis using a bimaxillary appliance fixed buccally. The advantages and disadvantages of this treatment option were discussed. The result was stable and made it possible to avoid an implant-prosthetic solution, which would undoubtedly have been more restrictive over time., (Copyright © 2024 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Background: To quantify the accuracy of Dolphin Imaging software in predicting soft tissue changes of Class II Division 1 incisor relationship treated by all first premolar extraction compared with actual changes., Methods: Pretreatment and post-treatment lateral cephalograms of 30 young adult subjects (25 females and 5 males; age range of 16 to 21 years) were imported and traced in Dolphin Imaging software (version 11.95). Tracings of actual treatment results and the Dolphin predicted treatment outcome were superimposed to calculate the prediction errors. The mean difference for the Holdaway soft tissue analysis and at each landmark was measured in both the X and Y axes. Paired t test was used to compare the statistical differences in Holdaway soft tissue analysis parameters., Results: There were significant differences between the predicted and actual values in three parameters of the Holdaway soft tissue analysis (P < 0.05). The overall accuracy of estimation was better in vertical direction than horizontal. Prediction of upper and lower lip landmarks was overestimated horizontally and underestimated vertically, whereas that belonging to chin was underestimated horizontally and overestimated vertically. Soft tissue nasion and soft tissue A-point were most accurately predicted, whereas the least accuracy was found in soft tissue chin region., Conclusions: Dolphin Imaging Software (version 11.95) can be accurate enough for use in patient communication and education but should be used with caution. It is most accurate in predicting soft tissue changes in the nasion and A-point regions, but least accurate in chin region., (Copyright © 2024 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: Adequate control of the vertical dimension is of great importance in orthodontic treatment. Although existing evidence is very limited, extraction of four premolars is thought to contribute towards improved control of anterior facial height compared with non-extraction treatment protocols. Thus, the aim of this retrospective cohort study was to compare the effect of fixed-appliance treatment with extraction of four premolars to non-extraction treatment on the skeletal vertical dimension., Methods: A consecutive sample of 76 children with skeletal hyperdivergence (49% male; mean age 11.9 years) was divided into two groups for treatment with either non-extraction (n = 31) or extraction of four premolars (n = 45). Baseline characteristics were comparable: overjet 5.1 ± 2.5 mm, overbite 2.4 ± 1.9 mm, ANB angle 4.6 ± 2.3°, and SN-ML angle 40.2 ± 3.5°. Patients were treated with standard edgewise fixed appliances with closing loops/sliding mechanics. Vertical skeletal and dental outcomes were measured on lateral cephalograms before and after treatment. Data were analyzed with linear regression at 5%., Results: Compared to non-extraction treatment, treatment with premolar extractions had no significant effect on the SN-ML angle (difference (Δ) = 0.07°; 95% confidence interval -0.90 to 1.01°; P = 0.88). Statistically significant changes between the extraction and non-extraction groups were only found for the parameters SNA (Δ -1.47°; P = 0.003), ANB (Δ -1.17°; P = 0.004), SN-OP (Δ -1.48°; P = 0.04), and L1-ML (Δ -6.39°; P < 0.001)., Conclusion: Orthodontic treatment of children with skeletal hyperdivergence using systematic extraction of four premolars had minimal effects on the vertical facial dimension compared to non-extraction treatment., (© 2022. The Author(s).)

Background: Up to 25% of the tooth extraction after root canal treatment could be attributed to the vertical root fracture (VRF). The treatment choice for teeth with VRF would mostly be the extraction despite some repairing methods were also reported. The repairing treatment result of VRF would mostly depend on the fixation strength and the bioactivity of the repairing materials, especially for the posterior teeth with high masticating stresses. This case report designed a novel surgical treatment approach for the VRF of posterior teeth., Methods: a maxillary premolar with buccal-palatal complete VRF was treated with a new dual-layered repairing approach using adhesive resin + iRoot BP Plus bioceramic cement to fill the modified fracture line with retention forms through the intentional replantation., Results: At the 24-month review, the tooth showed desirable periodontal healing and normal function., Conclusions: This case report indicated that the dual-layered repairing approach might be effective for saving the posterior teeth with VRF. Nevertheless, further clinical trials are needed for its long-term result., (© 2024. The Author(s).)

The new generation endodontic motors can perform different kinematics when they reach a certain predetermined level thanks to the integrated apex locator system. These actions consist of apical reverse, apical slow down and apical stop. The aim of this study is to compare this action's effect on apical debris extrusion. Sixty extracted human lower premolars were selected. Teeth are divided into four random groups (n = 15). Groups are prepared accordance to their group names as continuous rotation, apical slow down, apical reverse and apical stop. Extruded debris is collected into preweighted Eppendorf tubes and then calculated. One-way ANOVA test showed no statistically significant result between experimental groups. Similar debris extrusion values of all motion modes of the integrated endodontic motor can be interpreted that there will be similar debris extrusion and consequently similar postoperative pain on clinical setting. More in vitro and in vivo research is needed to make a conclusion., (© 2023 Australian Society of Endodontology Inc.)

Introduction: In this study, we compared the dentitional changes after Invisalign and conventional orthodontic treatment with 4 first premolar extractions., Methods: This retrospective study included 57 patients whose orthodontic treatment involved the extraction of 4 first premolars because of bialveolar protrusion. A total of 27 patients were treated with Invisalign (mean age, 25.5 ± 5.2 years) and 30 patients with the fixed appliance (mean age, 24.4 ± 5.8 years). The angular and linear changes of the maxillary and mandibular central incisors, second premolars, first molars, and second molars were measured from the recordings on the basis of the lateral cephalograms taken before and after treatment. The angular changes of the canines and second premolars were measured using panoramic radiographs., Results: The overbite and interincisal angle increased significantly in the Invisalign group compared with in the conventional fixed appliance group (P <0.05). The maxillary central incisors showed increased lingual tipping in the Invisalign group (P <0.05), whereas there was no statistically significant difference in the angular change of the mandibular incisors between groups (P >0.05). The maxillary first and second molars showed mesial tipping in the Invisalign group (P <0.05). The maxillary second premolars, first and second molars, and the mandibular second molars showed mesial movement in the Invisalign group (P <0.05)., Conclusions: The Invisalign group showed more statistically significant lingual tipping of the maxillary central incisors, distal tipping of the maxillary canines, and mesial tipping of the maxillary first and second molars after maximum retraction of the anterior teeth compared with the fixed appliance group., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

There has been a significant increase in robot-assisted dental procedures in the past decade, particularly in the area of robot-assisted implant placement. The objective of this case report was to assess the initial use of the Yomi Robot's assistance and haptic guidance during endodontic microsurgery. The robot was used during the osteotomy and root-end resection of the first and second upper left premolars. The report aims to inform clinicians of the initial implementation of this cutting-edge technology in endodontics and its potential to enhance endodontic microsurgery. The Yomi Robot was used in performing osteotomy and root-end resection during apical surgery in a patient presenting with symptomatic upper left first and second premolars. The treatment procedure was decided after clinical examination, chart data, and radiographic examinations, which showed periapical lesions on both premolars, taking into consideration the failed endodontic retreatment on the first premolar, the post and ceramic coronal restorations on both teeth, and the desire of the patient to save them. The Yomi Robot system provides auditory, visual, and physical guidance to clinicians during surgery while using a cone-beam computed tomography scan for precision planning with greater accuracy and minimized potential for human error. Further studies are needed to prepare a protocol for robotic-guided procedures in endodontics., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study evaluated the biomechanical performance of narrow-diameter implant (NDI) treatment in atrophic maxillary posterior teeth in aging patients by finite element analysis. The upper left posterior bone segment with first and second premolar teeth missing obtained from a patient's cone beam computed tomography data was simulated with cortical bone thicknesses of 0.5 and 1.0 mm. Three model groups were analyzed. The Regimen group had NDIs of 3.3 × 10 mm in length with non-splinted crowns. Experimental-1 group had NDIs of 3.0 × 10 mm in length with non-splinted crowns and Experimental-2 group had NDIs of 3.0 × 10 mm in length with splinted crowns. The applied load was 56.9 N in three directions: axial (along the implant axis), oblique at 30° (30° to the bucco-palatal plane compared to the vertical axis of the tooth), and lateral load at 90° (90° in the bucco-palatal plane compared to the vertical axis of the tooth). The results of the von Mises stress on the implant fixture, the elastic strain, and principal value of stress on the crestal marginal bone were analyzed. The axial load direction was comparable in the von Mises stress values in all groups, which indicated it was not necessary to use splinted crowns. The elastic strain values in the axial and oblique directions were within the limits of Frost's mechanostat theory. The principal value of stress in all groups were under the threshold of the compressive stress and tensile strength of cortical bone. In the oblique and lateral directions, the splinted crown showed better results for both the von Mises stress, elastic strain, and principal value of stress than the non-splinted crown. In conclusion, category 2 NDIs can be used in the upper premolar region of aging patients in the case of insufficient bone for category 3 NDI restorations., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Prasitwuttisak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: This review systematically evaluates the evidence related to comparisons between skeletal and conventional anchorage protocols in the treatment of bimaxillary proclination patients who underwent premolars extraction with respect to soft tissue profile changes, treatment duration and three-dimensional (3D) soft tissue changes., Methods: Electronic database search and hand search with no language limitations were conducted in the Cochrane Library, PubMed, Ovid, Web of Science, Scopus and ClinicalTrials.gov. The selection criteria were set to include studies with patients aged 13 years and above requiring extractions of upper and lower first premolars to treat bimaxillary proclination with high anchorage demand. Risk of bias assessment was undertaken with Cochrane's Risk Of Bias tool 2.0 (ROB 2.0) for randomised controlled trials (RCTs) and ROBINS‑I tool for nonrandomised prospective studies. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used for quality assessment. Results were summarised qualitatively; no meta-analysis was conducted., Results: Two RCTs and two nonrandomised prospective studies were included. According to the GRADE approach, there is low to very low quality of evidence that treatment using mini-implant anchorage may significantly change nasolabial angle, upper and lower lip procumbence, and facial convexity angle compared to treatment with conventional anchorage. Similarly, very low quality evidence exists showing no differences in treatment duration between treatments with skeletal or conventional anchorage., Conclusions: The overall existing evidence regarding the effect of anchorage protocols on soft tissue changes in patients with bimaxillary protrusion and premolar extraction treatment plans is of low quality., Trial Registration Number: PROSPERO CRD42020216684., (© 2022. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Purpose: The use non-invasive or minimally invasive methods to accelerate orthodontic tooth movements (OTM) is desirable. In this regard, low-level laser therapy (LLLT, photobiomodulation) and piezocision are suggested. However, because the efficacies of these methods remain controversial/inconclusive, we investigated and compared these two methods., Methods: Sixty-four quadrants in 32 patients were randomized into three parallel intervention groups of 22, 22, and 20 (6 parallel arms, n = 64 treatment/control sides). Bilateral first premolars were extracted and canine retraction commenced. In each group, one side of the mouth was randomly selected as control, while the other side underwent each of three interventions: LLLT (940 nm, 8 J, 0.5 W, 16 s, 12 sites), piezocision, and "LLLT + piezocision". At the 3rd, 6th, and 9th follow-up weeks, canine retraction and anchorage loss were measured. Data were analyzed statistically (α = 0.05)., Results: After 9 weeks, LLLT, piezocision, and LLLT + piezocision improved canine retraction by 0.51, 1.14, and 1.93 mm, respectively. LLLT accelerated canine retraction (compared to control) by 1.6-, 1.4-, and 1.2-fold in the 3rd, 6th, and 9th week, respectively. These statistics were 2.1-, 1.7-, and 1.5-fold for piezocision and 2.7-, 2.1-, and 1.8-fold for LLLT + piezocision. Compared to controls, each intervention showed significant retraction acceleration (p < 0.05). The effect of LLLT + piezocision was greater than that of isolated piezocision (p < 0.05), which itself was greater than that for isolated LLLT (p < 0.05)., Conclusion: All three methods accelerated OTM, with the combination of LLLT + piezocision producing the strongest and LLLT producing the weakest acceleration., (© 2022. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: To investigate the survival rate and clinical failure reasons of onlay and occlusal veneer restorations retrospectively, and to put forward valuable suggestions for the selection of clinical indications., Methods: A total of 102 patients and 124 teeth treated by one of the authors from 2016 to 2019 were subjected to CAD/CAM lithium silicate reinforced glass-ceramic onlay or veneer restorations of premolars and molars, including 43 teeth with pulp vitality, 81 endodontic treated teeth, and occlusal thickness of restoration was 1.5 mm. After four years of restoration, retrospective surveys were conducted to record the survival rate of restorations, the causes of restoration failure, and patient satisfaction rates, and the survival rate of restorations between vital teeth and endodontic treated teeth and among restored teeth was statistically analyzed by Chi-square test., Results: The survival rates of restorations on vital teeth and endodontic treated teeth were 95.5% and 90.0%, respectively, the average survival rate was 90.2%. The survival rates of vital teeth were higher than those of endodontic treated teeth without statistical difference. There was also no statistically significant difference among the tooth locations. The causes of failure included the cracking of the restoration, the loss of the restoration, the fracture of the abutment teeth, secondary caries below the adjacent contact point, and food impaction caused by the loosening of the adjacent contact point. The overall patient satisfaction rate was 91.5%., Conclusion: The 4-year survival rate of glass-ceramic onlays and occlusal veneers is lower than that of the full crown restoration, and there are more complications than that of the single-crown restorations. The design of the restoration should be carefully selected based on the vitality of the abutment tooth and the remaining amount of tooth tissue. When there is too little tooth structure left, a post and crown should be selected for restoration. Adequate strength and thickness of the restoration should be ensured to prevent food impaction. Due to the small amount of abutment tooth preparation, it has the advantages of less stimulation of the pulp and periodontal tissue, and can be recommended as a trial restoration.

Background: This single-centered randomized controlled clinical trial aimed to evaluate the effectiveness of micro-osteoperforations (MOPs) in accelerating the orthodontic retraction of maxillary incisors., Methods: Forty-two patients aged 16-40 were recruited and randomly assigned into two groups, one which underwent MOPs (MOPG) in the buccal and palatal region of all maxillary incisors immediately before the start of retraction and one which did not (CG). Eligibility criteria included the orthodontic need for maxillary first premolars extraction and space closure in two phases. The primary outcome of the study consisted of measuring the rate of space closure and, consequently, the rate of incisors' retraction using digital model superimposition 14 days later and monthly thereafter for the next 4 months. The secondary outcomes included measuring anchorage loss, central incisors' inclination, and root length shortening, analyzed using cone beam computed tomography scans acquired before retraction and 4 months after retraction. Randomization was performed using QuickCalcs software. While clinical blinding was not possible, the image's examinator was blinded., Results: Twenty-one patients were randomly assigned to each group. However, due to various reasons, a total of 37 patients (17 male and 20 female) were analyzed (mean age: 24.3 ± 8.1 years in the MOPG; 22.2 ± 4.2 years in the CG) during the trial. No statistically significant difference was found between the MOPG and the CG regarding the incisors' retraction measured at different time points at the incisal border (14 days, 0.4 mm vs. 0.5 mm; 1 month, 0.79 mm vs. 0.77 mm; 2 months, 1.47 mm vs. 1.41 mm; 3 months, 2.09 mm vs. 1.88 mm; 4 months, 2.62 mm vs. 2.29 mm) and at the cervical level (14 days, 0.28 mm vs. 0.30 mm; 1 month, 0.41 mm vs. 0.32 mm; 2 months, 0.89 mm vs. 0.61 mm; 3 months, 1.36 mm vs. 1.10 mm; 4 months, 1.73 mm vs. 1.39 mm). Similarly, no statistically significant differences were detected in the space closure, anchorage loss, central incisors' inclination, and radicular length between groups. No adverse effect was observed during the trial., Conclusions: MOPs did not accelerate the retraction of the maxillary incisors, nor were they associated with greater incisor inclination or root resorption. Trial registration ClinicalTrials.gov NCT03089996. Registered 24 March 2017- https://clinicaltrials.gov/ct2/show/NCT03089996 ., (© 2024. The Author(s).)

Objectives: To compare the pre- and postorthodontic treatment volumetric changes of the oral cavity proper (OCP) in extraction and nonextraction patients and to identify influencing variables., Materials and Methods: Pre- and posttreatment cone-beam computed tomography (CBCT) scans of patients undergoing orthodontic treatment with fixed labial appliances and who satisfied the inclusion criteria were individually landmarked. Linear, angular, and volumetric measurements were determined. Descriptive statistics, repeated measure analyses of variance, correlations, and stepwise regression statistical analyses were applied., Results: The CBCT scans of 54 patients who underwent the extraction of second premolars and/or extraction of second primary molars associated with agenic second premolars, and 59 nonextraction patients matched for crowding, were assessed. The mean age for both groups was 15 years. There was a statistically significant increase in the volume of the OCP for both the extraction and nonextraction groups, with the nonextraction group demonstrating a larger increase in the volume of the OCP. Gender, age, changes in mandibular and maxillary arch length, and changes in mandibular and maxillary intermolar width all influenced the change in the OCP volume., Conclusions: The volume of the OCP increased in growing patients with and without the extraction of the second premolars and/or extraction of second primary molars associated with agenic second premolars. Patients who did not have extractions as part of their orthodontic treatment demonstrated a greater overall increase in OCP volume., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and stability., Materials and Methods: An electronic search of the literature to June 2, 2023 was conducted using health science databases, with additional search of gray literature, unpublished material, and hand searching, for studies reporting nonsurgical patients with fixed appliances regarding sixteen sub-outcomes. Data extraction used customized forms, quality assessed with ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) and Cochrane RoB 2 (risk-of-bias) tool. GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessed certainty of evidence., Results: Thirty (29 retrospective studies, 1 randomized controlled trial) studies were included. Random-effect meta-analysis (95% CI) demonstrated maxillary (MD: -2.03 mm; [-2.97, -1.09]; P < .0001) and mandibular inter-first molar width decrease (MD: -2.00 mm; [-2.71, -1.30]; P < .00001) with four first premolar extraction; mandibular intercanine width increase (MD: 0.68 mm; [0.36, 0.99]; P < .0001) and shorter treatment duration (MD: 0.36 years; [0.10, 0.62]; P = .007) in the nonextraction group. Narrative synthesis included three and five studies for upper and lower lip-E plane, respectively. For American Board of Orthodontics Objective Grading System and maxillary/mandibular anterior alignment (Little's irregularity index), each included two studies with inconclusive evidence. There were no eligible studies for UK Peer Assessment Rating (PAR) score. Class I subgroup/sensitivity analyses favored the same results. Prediction interval indicated no significant difference for all outcomes., Conclusions: Four first premolar extraction results in maxillary and mandibular inter-first molar width decrease and retraction of upper/lower lips. Nonextraction treatment results in mandibular intercanine width increase and shorter treatment duration. There was no significant difference between the two groups regarding maxillary intercanine width, US PAR score, and posttreatment smile esthetics. Further high-quality focused research is recommended., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Introduction: Facial esthetics have always received much attention in orthodontic treatment, especially in young adult female patients. Three-dimensional (3D) soft-tissue changes after orthodontic extraction have not been fully explained. This study evaluated the 3D morphologic changes after orthodontic extraction in young female patients using a structured light scanner., Methods: Forty-five adult female patients aged 20-25 years were enrolled in our study. The treatment group consisted of patients who received orthodontic treatment with 4 premolar extractions, and the control group was composed of young female volunteers who had not undergone any orthodontic treatment. To monitor the soft-tissue changes, 9 morphologic regions and 12 landmarks were identified for the 3D deviation analyses. The spatial deviations of landmarks and regions in the x, y, and z directions were constructed for quantitative analysis. Color map images were constructed to visualize soft-tissue displacement as a qualitative evaluation. The paired sample test was used to compare differences at the beginning of the experiment (T0) and after 24 months (T1) in both groups. An independent t test with Bonferroni correction was performed to compare differences between the treatment and control groups. A linear regression test was performed between incisor retraction and changes in the perioral tissues., Results: Subtracting the effect of aging from the lip changes in the control group, the treatment group showed a statistically significant difference in the displacement of labrale superius (-1.37 mm), labrale inferius (-1.89 mm), the upper lip region (-0.98 mm), and the lower lip region (-1.36 mm) along the z-axis. No significant differences were found between the treatment and control groups in the temporal, parotideomasseteric, and buccal regions. Pearson correlation tests indicated a positive correlation between incisor tip retraction and changes in soft tissues (two-dimensional cephalometric analysis, 3D landmark measurements, and 3D regional measurements). The correlation coefficient ranged between 0.45 and 0.55., Conclusions: Three-dimensional soft-tissue changes were mainly concentrated in the upper and lower lip regions in adult female patients after the 4 premolars were extracted. For female patients aged 20-25 years with 4 extracted premolars, soft-tissue changes in the temporal, parotideomasseteric, and buccal regions were not clinically significant., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This study compared whether there is a difference in treatment time (TT) and efficiency when appointments are held once a month or at 2-week intervals in patients with Class II malocclusion treated with 2-premolar extractions METHODS: The patients of this retrospective sample were treated with the same orthodontic mechanics and divided into 2 groups according to frequencies of orthodontic appointments. Group 1 consisted of 18 patients (10 males, 8 females), with an initial mean age of 14.38 ± 1.38 years and appointments once a month. Group 2 consisted of 19 patients (9 males, 10 females), with an initial mean age of 14.12 ± 1.38 years and biweekly appointments. Edgewise fixed appliances with a slot size of 0.022 × 0.028 mm were used, and the anterior teeth were retracted en-masse with a rectangular wire and elastic chains. The Peer Assessment Rating and Objective Grading System indexes were measured in the dental models at the beginning and the end of treatment. Efficiency was assessed by dividing the percentage of improvement of each occlusal index concerning the multiplication of TT and the number of appointments., Results: Both groups presented similar Peer Assessment Rating and Objective Grading System indexes at the end of treatment. Groups 1 and 2 presented different TTs (28.06 and 22.05 months, respectively); however, there were no differences regarding the efficiency of both protocols., Conclusions: Patients with Class II malocclusion treated with 2-maxillary premolars had significantly shorter treatment times when seen on biweekly appointments than those with monthly appointments; however, there was no difference in efficiency between protocols., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objective: Compare the efficacy of the micro-osteoperforation (MOP) and corticotomy techniques in terms of maxillary canine retraction., Methods: Thirteen patients (5 females, 8 males; mean age, 18.07 ± 6.74 years) with healthy permanent dentition and requiring the extraction of maxillary first premolars were included in a split-mouth randomized clinical trial. Those subjects with previous orthodontic or endodontic treatment of the canines were excluded. At least 3 months post-extraction, MOPs and corticotomies were performed distal to the canines. Mini-screws with closed-coil springs (150 g) were used for the canine retraction. Dental casts were made at baseline (T0) and 3 months post-intervention (T1). Trained and calibrated examiners measured the distances from the canines to the second premolars on both sides. A signed-rank sum test was used to compare the amount of canine retraction achieved in 3 months (T0-T1) on the 2 sides., Results: Retraction (mm) at the incisal level was similar in the corticotomy (3.34 ± 1.01) and MOP patients (2.74 ± 1.10) (P = 0.11); furthermore, there were no differences in the degree of medial retraction between the corticotomy (2.56 ± 0.67) and MOP (2.27 ± 0.82) (P = 0.31) procedures. No adverse events were observed., Conclusion: There were not any clinically or statistically significant differences in retraction between the interventions. At 3 months, a MOP is as effective as a corticotomy in accelerating the rate of tooth movement.

Objective: To compare the effectiveness of the clear aligners with the traditional fixed appliances in the treatment of premolars extraction complex cases using the American Board of Orthodontics Objective Grading System (ABO-OGS)., Material and Methods: A single-centre, 2-parallel groups RCT with two arms. Forty severe crowding patients (14 males, 26 females; mean age: 21.40±2.42) who required four first premolars extraction were included and randomly allocated into two treatment groups: clear aligners therapy group (CAT), and fixed appliances therapy group (FAT). Cases complexities were measured on pre-treatment records using the Discrepancy index (DI). Post-treatment records were evaluated using the American Board of Orthodontics Objective Grading System (ABO-OGS). Two sample t-tests and Fisher's Exact tests were used to test for significant differences between the two groups. The statistical significance was set at P < 0.006 using Bonferroni's correction., Results: For the DI, the mean scores were 32.25 (± 4.33) in the CAT group and 33 (± 7.92) in the FAT group. In the CAT group, the total OGS score ranged between 6-33 points with an average of 17.50(± 7.41), whereas the total score in the FAT group went between 4-30 points with an average of 12.89 (± 6.31) with no significant differences between the two groups (P=0.05). When comparison of the successful cases between the two groups was made, 11 cases received passing scores, and 9 cases received failing scores in the CAT group. Whereas in the FAT group, 17 cases received passing scores, and 3 received a failing score. No statistically significant differences were found in the passing rates between of the CAT and FAT groups (P = 0.421)., Conclusions: According to the ABO-OGS total scores, there was no significant difference between the clear aligners and fixed appliances in the treatment of class I severe crowding cases with first premolars extraction in young adults. There were no differences between the two techniques in the OGS components scores except for the occlusal contacts, which were significantly better with the fixed appliances. When comparing the number of successful and failed cases between the two groups, no significant differences were noted, with the fixed appliances having a 30% higher success rate than the clear aligners, which must be considered clinically when choosing between these two techniques in the complex orthodontic cases treatment., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Aim: To investigate the healing after heterotopic mucosa transpositioning at dental implants and teeth., Materials and Methods: One hemimandible per dog (n = 4) was allocated to receive 3 implants (test), whereby 3 premolars on the contralateral side served as controls. After osseointegration, a Z-plasty was performed on the buccal aspect of the test and control sites to heterotopically move the zone of keratinized tissue (KT) into a region with non-keratinized tissue (nKT) and vice versa. Clinical measurements were performed before (T0) and at 12 weeks following heterotopic transposition (T1). Thereafter, specimens were processed for histological analysis., Results: Clinical measurements revealed that at T1, a band of KT was reestablished at teeth (mean: 2.944 ± 1.866 mm), whereas at implants, the transpositioned nKT resulted in a mucosa without any signs of keratinization (mean: 0 mm; p < .0001). At implant sites, the probing attachment level loss was more pronounced compared to tooth sites (-1.667 ± 1.195 mm and -1.028 ± 0.878 mm, respectively; p = .0076). Histologically, the transpositioned nKT, was accompanied by the formation of KT at the tooth but not at implant sites. The supracrestal soft tissues were statistically significantly higher at tooth compared to implant sites (2.978 ± 0.483 mm and 2.497 ± 0.455 mm, p = .0083). The transpositioned KT remained mostly unaltered in its morphological characteristics., Conclusions: The findings of this study indicate that: (a) transpositioned KT may retain its morphological characteristics; and (b) transpositioned nKM was accompanied by the formation of KT at the tooth but not at implant sites., (© 2023 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Objective: The purpose of this study was to prospectively evaluate the efficacy of a demineralized dentin matrix (DDM) in decreasing the initial inflammatory response of the gingiva and facilitating the repair and regeneration of soft tissue in alveolar ridge preservation., Methods: This clinical study employed a split-mouth design. Fourteen patients with a total of forty-four sites underwent extraction and alveolar ridge preservation (ARP) procedures. A Bilaterally symmetrical extraction operation were conducted on the premolars of each patient. The experimental group received DDM as a graft material for ARP, while the control group underwent natural healing. Within the first month postoperatively, the pain condition, color, and swelling status of the extraction sites were initially assessed at different time points Subsequently, measurements were taken for buccal gingival margin height, buccal-lingual width, extraction socket contour, and the extraction socket area and healing rate were digitally measured. Additionally, Alcian Blue staining was used for histological evaluation of the content during alveolar socket healing., Results: Both groups experienced uneventful healing, with no adverse reactions observed at any of the extraction sites. The differences in VAS pain scores between the two groups postoperatively were not statistically significant. In the early stage of gingival tissue healing (3 days postoperatively), there were statistically significant differences in gingival condition and buccal gingival margin height between the two groups. In the later stage of gingival tissue healing (7, 14, and 30 days postoperatively), there were statistically significant differences in buccal-lingual width, extraction socket healing area, and healing rate between the two groups. Furthermore, the histological results from Alcian Blue staining suggested that the experimental group may play a significant role in promoting gingival tissue healing, possibly by regulating inflammatory responses when compared to the control group., Conclusion: The application of DDM in alveolar ridge preservation has been found to diminish initial gingival inflammation after tooth extraction. Additionally, it has shown the ability to accelerate early gingival soft tissue healing and preserve its anatomical contour., Clinical Trial Registration: chictr.org.cn, identifier ChiCTR2100050650., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Xu, Peng, Zhou, Lin, Wang, Zhao, Zheng, Yang and Guo.)

Background : Endodontic success depends on the complete cleaning and shaping of the root canal. In order to achieve this goal, debris removal is essential. Even with improvements in instrument design, apical debris extrusion continues to be a cause of periradicular inflammation. The current study aimed to compare the amount of apically extruded debris throughout the canal instrumentation with TruNatomy, ProTaper Next, 2Shape rotary systems. Methods : A total of 60 freshly extracted single‑rooted mandibular premolars were used. An access opening was made, and a working length was estimated. The samples were arbitrarily allocated into three groups i.e. Group I: TruNatomy (n = 20), Group II: ProTaper Next (n = 20), Group III: 2Shape (n = 20). During the canal instrumentation, the extruded debris were collected in preweighed Eppendorf tubes. Post-instrumentation, the tubes were placed in a hot air oven at 140°C for five hours. For calculating the dry debris weight, the tube's pre-instrumentation weight was deducted from the post-instrumentation weight. The data was analysed using one‑way analysis of variance and post hoc Tukey's test. Results : Extrusion of debris was noted in all the specimens. TruNatomy rotary system showed least debris extrusion in comparison to ProTaper Next and 2Shape (P < 0.05). However, the results were statistically non-significant between ProTaper Next and 2Shape (P > 0.05). Conclusions : It was noted that all instruments apically extruded debris, with TruNatomy system being related to minimum extrusion., Competing Interests: No competing interests were disclosed., (Copyright: © 2023 Rajnekar R et al.)

Background: The purpose of this study was to compare the success rate of infrazygomatic mini-implants between adolescents and young adults., Methods: A total of 60 subjects of different age groups ie, (group I [adolescents]: 12-18 years, mean age: 14.9 ± 2.9 years; group II [young adults]: 19-25 years, mean age = 21.9 ± 3.1 years) were assessed in the study. En-masse retraction of maxillary anterior teeth was carried out with extraction of upper first premolars with infrazygomatic crest (IZC) mini-implants as anchorage units. Clinical parameters such as success rate, soft tissue thickness, maximum insertion torque, maximum removal torque, pain response, soft tissue response, and cone-beam computed tomography parameters such as embedded angulation, penetration depth, thickness of bone on buccal and palatal aspect of mini-implant, and peri-implant bone density were evaluated., Results: The success rate of IZC mini-implants in adolescents was found to be 96.6% and 98.3% in young adults respectively. There was no significant difference in success rate between the two groups. Intergroup comparison showed a significant difference (P < 0.05) in terms of maximum insertion torque, maximum removal torque, soft tissue thickness, cortical bone thickness, and peri-implant bone density values. Comparison between right and left side revealed a significant difference (P < 0.05) with regards to soft tissue response, soft tissue thickness, total bone thickness, cortical bone thickness, and peri-implant bone density., Conclusions: There was no significant difference in the success rate of IZC mini-implants between adolescents and young adults. Thus, the use of IZC mini-implants can be recommended in adolescents for successful orthodontic treatment., (Copyright © 2023 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Clear aligner therapy has become increasingly popular in recent years, although it has encountered several difficulties in premolar extraction treatment. These difficulties include anterior dentition, lingual tipping and extrusion. The design of the present clinical scheme usually set a tiny space between the anterior teeth before retraction in order to obtain an ideal outcome. The objective of our research was to analyze the effect of the existing spaces during retraction., Methods: Models including maxillary dentition without first premolars, maxilla, periodontal ligaments, gingiva, or aligners were constructed and imported to an ANSYS workbench. Five groups of models were created: without spaces and with 0.25, 0.50, 0.75 and 1.00 mm spaces between the anterior dentition. A 0.20 mm retraction step was applied to all the groups., Results: As the spaces between the anterior dentition increased, the bowing effect of the aligner caused by the passive forces decreased gradually. Accordingly, the degree of extrusion of the anterior dentition was alleviated significantly, while sagittal movement was reduced. However, the overall movement tended to be a bodily displacement rather than tipping. Meanwhile, maximum Von Mises stress of the periodontal ligaments (PDLs) was markedly decreased., Conclusion: These analyses indicate that spaces between the anterior dentition during anterior retraction are beneficial for decreasing the tendency for extrusion of the anterior dentition and require provision of anchorage. Appropriate spaces can be designed to lest the lingual tipping and extrusion effect of the anterior teeth while simultaneously reducing the maximum stresses on PDLs., (© 2023. Italian Society of Orthodontics.)

Introduction: The debate about whether malocclusion can or should be treated with or without extraction of premolars continues. This scoping review quantifies the literature, summarizes the outcomes researched and methods, and proposes a way to reduce uncertainty in this area., Methods: Electronic and gray literature searches were undertaken without language restriction, but non-English language titles and abstracts were not translated. A minimum of 2 people independently screened the titles and abstracts., Results: Searches identified 9010 articles, of which 3851 were duplicates; 5159 were screened, and 4617 were excluded (1092 laboratory or animal studies, 1219 case reports or series, 2306 with no information). By consensus, 399 articles contained information concerning differences between orthodontic patients treated with or without premolar extractions (143 were unclear). The majority (n = 372) reported outcomes in 8 areas. Fifty-seven were review articles (32 systematic reviews and 25 nonsystematic reviews or opinions). The most common research design in the remainder was a cohort (n = 280, 82% of 342 articles reporting primary data), of which a very large majority were considered retrospective (n = 249, 89% of articles reported for subjects over ≥2 time points). Only 28 (8% of articles reporting primary data) were judged to involve prospective data collection (4 randomized controlled trials [RCTs], 23 cohorts, 1 unclear design). Excluding reviews and unclear articles, 99% (332 out of 336) were considered observational research and only 1% were interventional., Conclusions: There was limited low-quality evidence that extracting premolars in orthodontic patients have a possible negative effect in 2 outcome areas and a positive effect in 1 outcome area. Most study reports were of low methodological quality, and further reviews are unlikely to provide new information. Investigators should concentrate on collecting primary data of outcomes important to patients. A protocol has been made available to help reduce methodological differences, assist future meta-analyses and increase the generalizability of findings: https://doi.org/10.17605/OSF.IO/CQ49Y., Competing Interests: Author credit statement Philip E. Benson contributed to conceptualization, methodology, validation, investigation, data curation, original draft preparation, visualization, supervision, and project administration; Ebrahim Alshawy contributed to conceptualization, methodology, investigation, and manuscript review and editing; Gavin D. Fenton contributed to investigation and manuscript review and editing; Tom Frawley contributed to investigation and manuscript review and editing; Sangeeta Misra contributed to investigation and manuscript review and editing; Teresa Ng contributed to investigation and manuscript review and editing; Paul O’Malley contributed to investigation and manuscript review and editing; and Gillian Smith contributed to investigation and manuscript review and editing., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

This case report describes a complex full-step class II high angle case in an adult patient treated with lingual straight-wire appliance, premolar extractions and orthognathic surgery. With the twofold aim of obtaining ideal occlusal relationship and aesthetic improvement, surgical treatment with appropriate biomechanical strategies, including extraction choice and torque control during space closure, are needed to achieve the planned results. This case report demonstrates the possibility of solving successfully severe sagittal, transverse and vertical discrepancies in an adult patient with surgical treatment by means of an invisible technique. This report also underlines the need for precise biomechanical control, including set-up overcorrections and an auxiliary spring to manage teeth inclination, in lingual orthodontics extraction cases., (Copyright © 2023 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: This study aimed to analyze the effects of premolar extraction treatment with vertical control on changes in the anatomy and aerodynamics of the oropharynx in Class II hyperdivergent malocclusion with nonsevere crowding., Methods: Thirty-nine patients with Class II hyperdivergent malocclusion were enrolled consecutively. All the participants underwent 4 premolar extractions. The high-pull J-hook and mini-implants were used to provide vertical control. Cone-beam computed tomography was performed before and after treatment. The participants were divided into a decreased lower vertical facial height group (n = 23) and an increased lower vertical facial height group (n = 16) on the basis of superimposition. The aerodynamic characteristics, including airway resistance (inspiration, R in ; expiration, R ex ) and maximum velocity (inspiration, Vmax in ; expiration, Vmax ex ) at inspiration and expiration, were calculated using computational fluid dynamics. Anatomic characteristics, including volume and cross-sectional area (CSA min ), were measured using the Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif)., Results: After treatment, the median volume and CSA min increased by 2357 mm 3 and 43 mm 2 , respectively, and median R in and Vmax ex decreased by 0.15 Pa/L/min and 0.24 m×s -1 , respectively, in decreased lower vertical facial height group. In contrast, the median CSA min decreased by 9.5 mm 2 in the increased lower vertical facial height group. All the changes were statistically significant (all P <0.05). Significant differences in volume, CSA min , R in , and Vmax ex were observed between the 2 groups., Conclusions: Vertical control might improve the anatomic and aerodynamic characteristics of the oropharyngeal airway during premolar extraction treatment of Class II hyperdivergent malocclusion with nonsevere crowding., (Copyright © 2023. Published by Elsevier Inc.)

Objective: To figure out whether premolar extractions treatment would influence the cant of the occlusal planes and thus affect dentoskeletal patterns in patients with different types of malocclusions., Materials and Methods: A total of 140 post-orthodontic treatment subjects (96 females, 44 males) were included in this study, and their lateral cephalograms and demographic information were collected and analysed. The patients were divided into extraction and non-extraction groups. The ANB, SNA, SNB, Wits, Facial Height Index (FHI), SN-MP, SN-AOP, SN-POP and AOP-POP angle were measured on the cephalograms. Other possible confounding factors were recorded. Data were analysed by univariate analysis, stratified analysis, multivariate analysis, and coefficient analysis., Results: After treatment, the changes in the AOP-SN, POP-SN and AOP-POP angle were statistically different between the extraction and non-extraction groups. The results were consistent in different skeletal malocclusions and extent of crowding according to stratified analysis. After adjusting all confounding factors, the cant of the posterior occlusal plane was flattened further by 2.14 degrees in the extraction group than the non-extraction group after orthodontic treatment, and the AOP-SN and AOP-POP angle would further increase by 1.72 and 3.81 degrees, respectively. Although no significant differences were found between the two groups, the SNA, ANB, and Wits in the extraction group decreased more with increased counterclockwise rotation of the mandible., Conclusion: Compared to the non-extraction group, there were more increases in the AOP-SN and AOP-POP angle and more posterior flattening in patients with four premolar extractions despite different types of dentoskeletal malocclusion, which were correlated to the change of variables in sagittal and vertical dimensions such as Wits and FHI., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)