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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. [ABSTRACT FROM AUTHOR]

Purpose: To determine the change in the sagittal and vertical position of mini-implants placed in the maxilla during distal movement of the entire maxillary dentition. Materials and Methods: Overall, 28 mini-implants (1 placed on each side in 14 patients) were evaluated in healthy patients aged 15 to 25 years old. CBCTs were taken immediately after leveling and aligning prior to distalization (T1) and after 6 months (T2) to evaluate the distal movement of the maxillary teeth and position of the mini-implants. The vertical and sagittal angulation of each mini-implant was measured at T1 and T2. The linear distance between the mini-implant and the alveolar crest, the maxillary sinus, the maxillary second premolar, and the maxillary first permanent molar were measured. The change in angulation and the linear displacement of the mini-implant were evaluated in the vertical and sagittal plane. Wilcoxon signed rank test was performed to determine if there was a statistically significant change in the position of the mini-implant. Results: Vertically, there was a significant change in the linear distance between the mini-implant and the alveolar crest on the right side (P ≤ .006) as well as the mini-implant and the maxillary sinus on the left side (P ≤ .003). Sagittally, there was a statistically significant rotation of the mini-implant occlusally (left side P ≤ .004 and right side P≤ .002). The head and tip of the mini-implant were displaced toward the maxillary second premolar and away from the maxillary first permanent molar, respectively. There was a significant relative displacement of the mini-implant anteriorly away from the maxillary first permanent molar (left side P ≤ .026 and right side P ≤ .041) and closer to the maxillary second premolar (left side: P ≤.011 and right side: P≤ .002). Conclusions: There was a statistically and clinically significant rotation of the mini-implant in the vertical and sagittal direction during distal movement of the entire maxillary arch. The linear displacement of the mini-implant was more pronounced in the sagittal direction than the vertical direction. [ABSTRACT FROM AUTHOR]

Purpose: To investigate how well an implant stability quotient (ISQ) represents resonance frequency. Materials and Methods: Benchtop experiments on standardized samples that replicated a mandibular premolar site were conducted to correlate an ISQ value and a resonance frequency to synthetic bone density and an incremental insertion torque; then, a frequency spectrum analysis was performed to check the validity of the resonance frequency analysis (RFA). Brånemark Mk III implants (4 × 11.5 mm; Nobel Biocare) were placed in Sawbones test models of five different densities (40, 30, 40/20, 20, and 15 PCF). An incremental insertion torque was recorded during implant placement. To perform stability measurements, the test models were partially clamped in a vise (unclamped volume: 10 × 20 × 34 mm). A MulTipeg (Integration Diagnostics) was attached to the implants, and a Penguin (Integration Diagnostics) RFA measured ISQ. Simultaneously, the MulTipeg motion was monitored via a laser Doppler vibrometer and processed by a spectrum analyzer to obtain the resonance frequency. Tightness of the clamp was adjusted to vary the resonance frequency. A statistical analysis produced a linear correlation coefficient (R) among the measured ISQ, resonance frequency, and incremental insertion torque. Results: The resonance frequency had high correlation to the incremental insertion torque (R = 0.978), confirming the validity of using RFA for this study. Measured ISQ data were scattered and had low correlation to the resonance frequency (R = 0.214) and the incremental insertion torque (R = 0.386). The spectrum analysis revealed the simultaneous presence of multiple resonance frequencies. Conclusions: For the designed benchtop tests, resonance frequency does indicate implant stability in view of Sawbones density and incremental insertion torque. However, ISQ measurements do not correlate to the resonance frequency and may not reflect the stability when multiple resonance frequencies are present simultaneously. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the dimensional accuracy of implant impressions obtained using five different tray types and two techniques. Materials and Methods: A partially dentate maxillary Kennedy Class II model was created as a reference model through 3D printing. Then, implant analogs 4.3 mm in diameter were placed at the first premolar, first molar, and second molar sites. Five types of trays were used to create impressions: (1) metal stock trays, (2) plastic stock trays, (3) custom trays fabricated using liquid crystal display (LCD), (4) custom trays fabricated using fused deposition modeling (FDM), and (5) custom trays fabricated using urethane dimethacrylate (UDMA) resin. Open and closed tray techniques were also compared. In total, 150 impressions were obtained. The reference model and impressions were scanned using a laboratory scanner. Additionally, the positional and angular deviations of implants with different tray types and techniques were evaluated using the superimposition method. Results: There was no statistically significant difference (P > .05) between the impression accuracy with the different tray types and impression techniques. The angular deviations with plastic and UDMA trays were greater than those with metal, FDM, and LCD trays. Angular deviation at the second molar was greater when using closed plastic trays compared to open plastic trays. The highest and lowest positional deviations were observed at the first molar implant with an open plastic tray impression (mean ± SD of 62.46 ± 28.54 mm) and a closed LCD tray impression (36.59 ± 29.93 mm). The greatest angular deviation was observed with an open FDM tray impression at the first premolar implant (0.067 ± 0.024 degree), and the lowest angular deviation was observed with a closed metal stock tray impression at the second molar implant (0.039 ± 0.025 degree). Statistical differences were detected using the Mann-Whitney U test for paired groups and the Kruskal-Wallis test for groups with more than three comparisons (P > .05). Conclusions: Plastic and metal stock trays or conventional and 3D-printed custom trays can be used to obtain implant impressions for maxillary partially edentulous arches with similar dimensional accuracy. The five tray types and two techniques may be safely used to obtain impressions of partially edentulous maxillary arches with three implants. [ABSTRACT FROM AUTHOR]

This canine in vivo study assessed the effect of recombinant human platelet-derived growth factor (rhPDGF) on the healing of periapical tissues following apical surgery. From a total of 96 premolar teeth, 64 teeth from six beagle dogs (2 years old) were classified as experimental and were randomly assigned to four experimental groups (16 teeth per group). After having the pulp extirpated, leaving teeth open to the oral cavity for 1 week, and sealing with an immediate restorative material for 8 weeks, nonsurgical endodontic treatment was performed. A split-mouth design was used, and intra-animal randomization of treatment sides was applied to the groups as follows: apical curettage + 1.5-mm root-end resection (Group 1); apicoectomy + mineral trioxide aggregate (MTA) root-end filling (Group 2); apicoectomy + MTA root-end filling + rhPDGF (Group 3); and apical curettage + rhPDGF (Group 4). The animals were sacrificed 24 months after apical surgery, and histologic and µCT analyses were performed for bone volume loss (BVL). Group 1 showed partial resolution of the periapical lesions without signs of tissue regeneration (BVL: 49.09 ± 10.97 mm3). Group 2 had minimal bone regeneration and showed cementum reformation in 9 teeth, with no direct attachment to the MTA (BVL: 35.34 ± 10.97 mm3). Group 3 showed regeneration of all damaged apical tissues without direct contact between the cementum and MTA (BLV: 4.51 ± 1.55 mm3). Group 4 showed regeneration of PDL, bone, and cementum and attachment of functional cementum fibers (BVL: 2.82 ± 2.3 mm3). The difference in BVL was statistically significant only for Groups 1 and 2 (P < .05). rhPDGF may help regenerate apical tissue structures following apical surgery. [ABSTRACT FROM AUTHOR]

Purpose: To compare the marginal and internal fit of monolithic zirconia (MZ) 3-unit fixed dental prostheses (FDPs) fabricated using two CAD/CAM workflows: full-chairside (FCH) and lab (LAB). Materials and Methods: The right maxillary first premolar and first molar were prepared for MZ 3-unit FDPs on a typodont. CEREC Primescan digiOzed the typodont model 15 Omes. A total of 30 FDPs was fabricated using two processes: FCH (n = 15) and LAB (n = 15). FCH and LAB FDPs were designed using CEREC SW 4.5.1 and Exocad and milled using CEREC MC X and Zirkonzhan 600/V3, respecOvely. A fast-sintering protocol was used in both groups. A dual-scan technique was used to assess the cement space at the occlusal surface (OC), axial wall (AX), and margin (MA). StaOsOcal analysis of the results was performed using univariate ANOVA with Scheffè post hoc test (a = .05). Results: Measurements in the FCH and LAB groups were within the clinically acceptable marginal and internal fit. The fit of FCH FDPs at MA, AX, and OC was 77.50 ± 29.99 μm, 99.67 ± 21.58 μm, and 150.03 ± 30.78 μm, respecOvely. The fit of LAB FDPs at MA, AX, and OC was 100.27 ±27.06 μm, 116.53 ±17.90 μm, and 142.30 ±19.00 μm, respecOvely. The difference between the two groups was not staOsOcally significant. Conclusions: MZ 3-unit FDPs fabricated using FCH have clinically acceptable marginal and internal fit. This result verifies the ability of FCH workflow to fabricate MZ mulOunit FDPs in a single visit. [ABSTRACT FROM AUTHOR]

This randomized controlled trial aimed to determine the clinical efficacy of xenogeneic collagen membrane (XCM) derived from porcine peritoneum in combination with a coronally advanced flap (CAF) in the management of gingival recession defects and to compare the outcomes to those of connective tissue grafts (CTGs). A total of 12 systemically healthy individuals presenting with 30 isolated/multiple Cairo RT 1/2 gingival recession defects in maxillary canines and premolars were randomly treated either with CAF + XCM or CAF + CTG. Recession height (RH), gingival biotype (GB), gingival thickness (GT), width of keratinized gingiva (WKG), and width of attached gingiva (WAG) were recorded at baseline and at 3, 6, and 12 months. Patient perceptions of pain and esthetics and the modified root coverage esthetic score (MRES) were also documented. From baseline to 12 months, both groups showed a significant reduction in mean RH (CAF + CTG: 2.73 ± 0.79 mm to 0.33 ± 0.61 mm; CAF + XCM: 2.73 ± 0.88 mm to 1.20 ± 0.77 mm). At 12 months, CAF + CTG sites had a mean root coverage percentage (MRC%) of 85.60% ± 28.74%, whereas CAF + XCM sites had an MRC% of 55.13% ± 31.22%. CAF + CTG-treated sites had significantly better outcomes, with a greater number of sites achieving complete root coverage (n = 11) and higher MRES scores than the porcine peritoneal membrane group (P < .05). [ABSTRACT FROM AUTHOR]

Purpose: To compare bone substitutes composed of glycated collagen with synthetic micro-sized (1 to 10 µm) hydroxyapatite (OB) vs non-cross-linked collagen matrix with large-particle (250 to 1,000 µm) bovine-derived hydroxyapatite (BOC). Materials and Methods: The P1 to P4 premolars were bilaterally extracted from the mandibles of 19 Beagle dogs. After 21 days, osteotomies were created in each dog that received OB or BOC and were covered with a collagen membrane or were left untreated. The animals were randomly divided into three groups based on sacrifice time (4, 12, or 24 weeks). The right and left hemimandibles were trimmed to facilitate imaging and histology, and all tissues were placed in 10% neutral-buffered formalin. Microcomputed tomography (MicroCT 40 Scanner, Scanco) was used to analyze bone sections. Bone volume, residual material volume, and bone mineral density were determined for each treatment site (OB and BOC) based on a volume of interest that encompassed the original defect. Additionally, blinded histopathologic assessment (based on the ISO 10993-6 scoring system) and histomorphometry were performed on sections ground to < 100 µm thick and stained with Stevenel's blue. Results: No clinical side effects were noted. No statistical differences were observed for OB vs BOC regarding the mineral volume percentage. Compared to OB, BOC had significantly higher mean mineralization densities at 12 weeks (P < .01), but this difference did not extend to 24 weeks. For residual grafting material, bone maturation, alveolar ridge restoration, and inflammatory response, OB showed a residual amount of bone graft and no statistical differences compared to BOC. Conclusion: Both OB and BOC represent valid treatment options for critically sized bone defects. Both bone fillers outperformed the sham-operated, ungrafted (empty) control, demonstrating statistically improved bone growth and ridge restoration. [ABSTRACT FROM AUTHOR]

Objective: This study compared the achieved tooth movement to that predicted in the preliminary simulated digital treatment plan between adults and teenagers. Materials and methods: Records of 60 patients (30 adults; mean age: 36.6 ± 11.36 years, and 30 teenagers; mean age: 16.23 ± 2.25 years) were randomly selected. Initial and predicted models were obtained from the initial simulated treatment plan. The first model of the refinement scan was labeled as achieved. SlicerCMF software (version 3.1; https://www.slicer.org) was used to superimpose the achieved and predicted digital models over the initial ones with regional superimposition on relatively stable first molars. 600 teeth were measured in each group for horizontal, vertical, angular movements, and transverse dimensions. Accuracy was defined as the achieved amount of movement minus predicted and was calculated for each individual and compared between teens and adults. Results: The mandibular inter-canine width accuracy was statistically significant between groups (p = 0.050). Significant under-correction in horizontal movements was noted for mandibular first premolars in teenagers compared to adults (p = 0.037). There was considerable over-correction in horizontal movements for mandibular central and lateral incisors between groups (p < 0.05). No significant difference was observed between groups in the vertical plane. Rotations were underachieved for maxillary first premolars, more in adults than teenagers (p = 0.017). Conclusion: The accuracy of achieved versus predicted tooth movement between adults and teenagers was significant for the inter-canine width. Mandibular central and lateral incisors showed significantly greater over-correction in adults in the horizontal plane. The accuracy of rotations and vertical movements was comparable. [ABSTRACT FROM AUTHOR]

ABSTRACT Linear enamel hypoplasias (LEHs) are development defects appearing as lines or grooves on enamel surfaces. Forming when physiological stressors disrupt developing teeth, LEHs provide retrospective insight into stress experienced in early development. Here, LEHs in Cayo Santiago rhesus macaques (Macaca mulatta) were observed with respect to decade of birth, whether an individual was transferred from the free‐ranging colony to the captive facility during probable crown formation periods, and matriline of birth. It was hypothesized that later decades would exhibit higher prevalence than earlier decades as climatic conditions in Puerto Rico worsened over time. Transfer was expected to affect LEH formation because the process of transfer, and subsequent restriction to captivity, is thought to be stressful. Matriline membership was hypothesized to relate to LEH formation because there is some evidence of a genetic influence on susceptibility to form LEH and because offspring of matrilines of different dominance ranks are known to experience different levels of aggression. Lower third premolars with minimal enamel surface wear were scored for LEH using a digital microscope, while a follow‐up analysis of the two matrilines with the most extreme differences in LEH frequency was conducted using enamel surface profiles. Results were: (1) individuals born during the 1990s had significantly greater LEH prevalence than those born in the 1960s, (2) transferred individuals exhibited weak evidence of greater LEH prevalence than nontransferred comparison groups, and (3) matrilines did not differ in LEH expression in the initial or follow‐up analysis. Although sample sizes were small for some comparisons, these results suggest that not all decades saw an equal prevalence of LEH, that there might be a small effect of transfer from free‐ranging to captive conditions on LEH prevalence that is difficult to detect, and that the matriline into which an individual is born is not related to LEH expression. [ABSTRACT FROM AUTHOR]

Introduction: Knowledge of the facial skeleton and its overlying soft-tissue is essential in determining facial harmony. Additionally, an individual's growth pattern may influence post-treatment facial profiles and needs to be considered during treatment planning. Aim: To evaluate the soft-tissue profile changes in treated Class-II malocclusion patients with varied mandibular growth patterns and to compare these changes with patients having a skeletal Class-I relationship and a balanced facial profile. Materials and Methods: The present cross-sectional cephalometric study was conducted in the Department of Orthodontics, Faculty of Dental Sciences, SGT University, Gurugram, Haryana, India, from June 2021 to December 2022. The study included 210 lateral cephalograms of 120 patients. The cephalograms were divided into four groups based on the Frankfort horizontal Mandibular plane Angle (FMA): Group-1 (control, n=30): skeletal Class-I (FMA=22°-28°); Group-2 (n=30): skeletal Class-II with a horizontal growth pattern (FMA<22°); Group-3 (n=30): skeletal Class-II with an average growth pattern (FMA=22°-28°); and group-4 (n=30): skeletal Class-II with a vertical growth pattern (FMA>28°). All patients in the groups-2,3, and 4 were treated with all first premolar extractions using a 0.022" McLaughlin, Bennett and Trevisi (MBT) appliance. The student's t-test and post-hoc test was used to analyse skeletal, dental and soft-tissue parameters using Statistical Package for the Social Sciences (SPSS) software (version 22.00 for Windows; SPSS Inc., Chicago, USA). Results: Of the total, 120 patients, 52 were males and 68 females with an age range of 18-28 years. On intergroup analysis, significant changes (p-value<0.05) in the Sella, Nasion and A point (SNA) and Sella, Nasion and B point (SNB) angles were observed in group-3. Clinically insignificant changes were found in the A point, Nasion and B point (ANB) angle across all experimental groups. However, a significant change (p-value<0.001) in the post-treatment ANB angle was observed in group-2, followed by group-3 and 4 when compared with group-1. The soft-tissue profile angle showed a significant change in Group-2 when compared with Group-1 (p-value=0.012). Conclusion: The post-treatment soft-tissue profiles of the experimental groups were comparable to the balanced profile of the control group patients. [ABSTRACT FROM AUTHOR]

Bicuspid aortic stenosis is a common pathology, typically seen in patients a decade younger than those with tricuspid valves. Surgical aortic valve replacement has been the mainstay treatment for bicuspid disease, especially considering the prevalence of concomitant aortic aneurysmal pathology. Transcatheter aortic valve replacement has shown equivalent results in bicuspid compared to tricuspid pathology in highly selected patient populations in single-arm registries and observational studies. For older patients with favorable bicuspid pathology, TAVR is reasonable. However, as younger patients with longer life expectancy are now being treated with TAVR, what is "best" is a question only answered by a well-designed randomized controlled trial. Herein, we describe the current evidence for treating bicuspid aortic stenosis and provide a framework for future trials. Yet, the question of equipoise remains, and who will we enroll? [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the influence of multiplanar reconstruction thickness on the detection of peri‐implant bone defects with a standalone zirconia implant and compare it to when another implant is in the vicinity using cone‐beam computed tomography (CBCT). Materials and Methods: Five dry human mandibles were used to create twenty implant sites in the second premolar and first molar regions. The OP300 Maxio was used to acquire CBCT images (90 kVp, 6.3 mA, 5 × 5 cm FOV, and 0.125 mm3 voxel size) before and after creating 3 mm peri‐implant bone defects in the buccal aspect of the premolar region. Half of the scans featured a single zirconia implant in the premolar region, while the others had two implants in the premolar and molar regions. Three reconstruction thicknesses (0.125 mm, 1 mm, and 2 mm) were considered for the multiplanar reconstruction analyses. Five oral and maxillofacial radiologists assessed the detection of peri‐implant bone defects using a 5‐point scale. Diagnostic parameters were calculated and compared using Two‐way ANOVA (α =.05). Results: The studied factors showed no significant influence on the diagnosis of peri‐implant bone defects (p >.05). Diagnostic performance was notably higher with a single implant, especially with a 2‐mm reconstruction thickness (AUC = 0.88, sensitivity = 0.68, specificity = 0.94). Although the differences were not statistically significant, the results were more modest when two implants were present (AUC = 0.80, sensitivity = 0.58, specificity = 0.82). Conclusions: The presence of an adjacent zirconia implant and variations in reconstruction thickness did not influence the detection of 3 mm buccal peri‐implant bone defects on CBCT images. [ABSTRACT FROM AUTHOR]

Objectives: Whether gemination or fusion, double teeth are rare worldwide, including Africa based on few published data. New cases from the continent are tallied, and anomalies potentially associated with double teeth are identified. These findings should interest a range of dental researchers. Methods: The presence of double teeth was recorded in 97 modern and premodern North and sub‐Saharan African samples (5631 inds.). They and coexistent anomalies are described relative to published examples. Prevalence was estimated as possible, using a Poisson model for 95% confidence intervals (CI). Results: Three maxillary double teeth were identified: a primary left lateral incisor in a Nubian child (1938–1756 BC), permanent left central incisor in an adult Egyptian (3650–3500 BC), and permanent right central incisor in a modern (19th century) adult from Guinea. Each co‐occurs, respectively, with a talon cusp, peg lateral incisor and, in the latter individual, second premolar crown variation with rotation, and third molar dens evaginatus. Double tooth prevalence is 0.048% (CI 0.001%–0.270%), with regional variation, in premodern, and 0.000% in modern North Africans. It is 0.000% for premodern and 0.048% for modern sub‐Saharan Africans (0.008%–1.714%). Conclusions: The double incisors are comparable to other global examples, indicative of common developmental processes during odontogenesis. Prevalence is lower than published modern rates, to suggest some exceptionality in Africans as reported earlier for other dental variants. Finally, though circumstantial, double teeth and accompanying anomalies may share an etiology. Continuing research overall, and in Africa specifically, will promote an improved understanding of double teeth formation and expression. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate and compare the fracture resistance of MOD inlay preparations restored with two different lithium disilicate glass ceramics. Materials and Methods: Standardized MOD inlay cavities were prepared on 64 human permanent premolar teeth and divided into two groups to be restored with lithium disilicate glass-ceramic materials, i.e. Group I with IPS e.max Press HT and Group II with Shofu Vintage LD Press T. The fracture resistance was assessed using a universal testing machine and recorded in Newtons (N). Statistical analysis was done using SPSS software (Version 17.0, IBM, USA). P <0.05 was set as a statistically significant level. Unpaired Student's t -test was used to compare the fracture resistance values of both groups. Results: The mean fracture resistance value obtained for Group I (IPS e.max Press HT) was 565.04 N while that obtained for Group II was 732.75 N. Statistically significant difference was found in this intergroup comparison (P = 0.002). Conclusion: The fracture resistance of MOD inlay preparations restored with Vintage LD Press T (Shofu) was significantly higher than those restored with IPS e.max Press HT (Ivoclar Vivadent). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AbstractHorizontal bone loss (HBL) and dehiscence are common supportive tissue defects. This study evaluated the stress distribution in the presence of HBL or dehiscence and two types of fiber posts. Twelve premolars that were endodontically treated (Model-E), restored with conventional (Model-C), and bundle (Model-B) post were modeled. Bone defects were created as control (Model-1), with 4 mm (Model-4) and 8 mm (Model-8) HBL, and dehiscence involving two-thirds of the root (Model-D). HBL was included in all aspects of the models, while dehiscence was confined to the buccal aspect. The models were subjected to a 200 N force, and von Mises stress was analyzed. Model-B1 showed higher stress than Model-C1 but was more homogeneous. In Model-D, the stress was limited to the area without bone and only occurred at the buccal aspect. The highest stress was observed in Model-B8. The presence of a post caused a 2–5.8 times increase in stress. When the crown–root ratio was 1:0.8, stress was in the coronal two-thirds of the root, while at a ratio of 1:0.3, stress was distributed throughout the entire root. Bundle post with 8 mm HBL increased the stress 5.8 times. HBL resulted in stress extending beyond the marginal bone, while dehiscence did not. [ABSTRACT FROM AUTHOR]

The palatal anchorage device (PAD) is commonly used in fixed appliance for anchorage, but the biomechanics of PAD in patients treated with clear aligners(CAs)remains poorly understood, especially in its elastic mode and force magnitude. This study aimed to assess the biomechanical effects of using PAD for retraction during clear aligner treatment (CAT) with the extraction of two maxillary first premolars. Four finite element models were created: (1) Incisors retraction (IR) with active contraction of the clear aligner only; (2) IR with PAD using different forces (50,75,100 g) or not; (3) PAD without IR (forces of 50,75,100 g), and (4) Different elastic directions (D1, D2, D3) from aligner to PAD without IR. IR caused lingual tipping and extrusion of the central incisors, as well as mesial and buccal tipping of the first molar. PAD during IR provided strong anchorage for the first molar, with elastics slightly increasing the lingual tipping and extrusion of the central incisors. Elastics applied to the U-shaped arch led to central incisor intrusion and reduced lingual retraction. The highest stress was observed on the mesial attachment of the canine. PAD effectively reinforced posterior anchorage in CAT, while anterior positioning facilitated anterior teeth intrusion. The biomechanical importance of the canine's mesial attachments in maxillary teeth treatment planning was highlighted. [ABSTRACT FROM AUTHOR]

Background: To compare the impacts of different remineralizing agents on demineralized enamel, we focused on chitosan nanoparticles (ChiNPs) and silver nanoparticles (AgNPs). Methods: This study was conducted on 40 extracted human premolars with artificially induced demineralization using demineralizing solution. Prior to the beginning of the experimental procedures, the samples were preserved in artificial saliva solution. The nanoparticles were characterized by transmission electron microscopy (TEM) and teeth were divided into four equal groups: Group A was utilized as a control group (no demineralization) and received no treatment. Group B was subjected to demineralization with no treatment. Group C was subjected to demineralization and then treated with ChiNPs. Group D was subjected to demineralization and then treated with AgNPs. The teeth were evaluated for microhardness. The enamel surfaces of all the samples were analysed by scanning electron microscopy (SEM) for morphological changes and energy dispersive X-ray analysis (EDX) for elemental analysis. Results: The third and fourth groups had the highest mean microhardness and calcium (Ca) and phosphorous (P) contents. SEM of these two groups revealed relative restoration of homogenous remineralized enamel surface architecture with minimal micropores. Conclusion: Chitosan nanoparticles (NPs) and silver NPs help restore the enamel surface architecture and mineral content. Therefore, chitosan NPs and AgNPs would be beneficial for remineralizing enamel. [ABSTRACT FROM AUTHOR]

Background: This clinical study aims to compare postoperative pain after single-visit root canal treatment of teeth with asymptomatic apical periodontitis using epoxy-resin-based AH Plus and calcium silicate-based Endosequence BC sealers with or without sonic activation. Methods: This study included 72 individuals with one first or second mandibular premolar tooth with asymptomatic apical periodontitis. They were randomly divided into four groups according to the root canal sealer (AH Plus or Endosequence BC) and activation protocol (sonic activation or non-activation) (n = 18). The participants were ask to rate their postoperative pain intensity on a NRS scale as none, minimal, moderate, or severe after 24 h, 48 h, 72 h, and 7 days following treatment. Patients were also asked to record the number of prescribed analgesic medication tablets (400 mg of ibuprofen) taken. Statistical analysis were performed using the Mann-Whitney U test, the Friedman test, the Spearman's correlation test, the Chi-square test. Significance level was established at 0.05. Results: There was no statistically significant difference in postoperative pain scores or analgesic intake between AH Plus and Endosequence BC sealers regardless of the activation protocol (p > 0.05). There was no statistically significant difference in postoperative pain scores between the sonic activation and non-activation groups (p > 0.05). A weak positive correlation was detected between Endoactivator sonic activation and sealer extrusion (r = 0.36). Conclusions: AH Plus and EndoSequence BC root canal sealers showed similar results in terms of prevalance and intensity of postoperative pain. Sonic activation and non-activation groups had similar postoperative pain scores. Clinical trial registration: The study was retrospectively registered with ClinicalTrials.gov (NCT06403293). Date of Registration: 07/05/24. [ABSTRACT FROM AUTHOR]

Deciduous dentition of extinct mammals has traditionally received little attention based on its poor representation in the fossil record. However, several aspects related to this tooth locus could have important evolutionary significance (time of replacement, retention throughout life, and morphology). In this work, we described a new specimen from late Oligocene levels of Cabeza Blanca (Chubut Province, Argentina). This fossil corresponds to a maxillary fragment with a deciduous premolar (DP4) assigned herein to Cephalomys arcidens based on morphological characteristics, size, and comparisons with other late Oligocene-Early Miocene caviomorphs. It can be identified as a DP4 due to its mesiodistally longer than wide diameter, shallow flexi, complex tooth morphology, and its position in the maxillary fragment. This is the first description of the DP4 of a Cephalomyidae and the last unknown dental locus of Cephalomys arcidens. Now, C. arcidens is one of the better-known late Oligocene caviomorphs since it is recognised through the complete dentition, crania, and mandibles. In addition, this new information would be used to evaluate the importance of deciduous dentition in resolving phylogenetic relationships in the enigmatic cephalomyids in particular and in Caviomorpha in general. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate and compare the ion-releasing capability of three different restorative systems at the restoration/tooth interface elemental analysis using energy-dispersive X-ray technique. Additionally, micromorphological patterns of the restoration/tooth interfaces was investigated. Materials and methods: Eighteen freshly extracted sound human premolars were collected for the study. The premolars were randomly assigned into 3 groups (n = 6) based on the type of restorative materials used: Giomer (Beautifill II), ion-releasing composite (Activa Presto), and RMGI (Riva Light Cure). Half of the specimens in each group were tested after 24 h (the "immediate group"), while the remaining half were tested after 6 months of storage in deionized water (the "delayed group"). Standardized box-shaped cavities along the cervical area of teeth crowns and restored them with the assigned restorative material following manufacturers' instructions. The specimens were sectioned buccolingually into 2 halves. One half of each specimen was subjected to elemental analysis using energy-dispersive X-ray technique (EDX), while the remaining half was sputter coated and underwent micromorphological analysis of the restoration/tooth interface using a scanning electron microscope (SEM). The collected data from elemental analysis test were tabulated and subjected to statistical analysis. Results: The two-way ANOVA test showed significant differences in both phosphorus and calcium levels among the tested restorative systems (p < 0.05). In the immediate subgroup, RMGI recorded the highest phosphorus level (0.1527), followed by the ion-releasing composite (0.1172), while Giomer exhibited the least levels (0.0326) (p < 0.05). The ion-releasing composite group had the highest calcium level (0.2797), followed by RMGI (0.248), and Giomer (0.2385) respectively (p < 0.05). In the delayed subgroups, Giomer recorded the highest phosphorus level (0.1526), followed by the ion-releasing composite (0.1058), and RMGI group (0.0466) respectively (p < 0.05). RMGI had the highest calcium level (0.2801), followed by the ion-releasing composite (0.2659), and Giomer had the lowest level (0.1792) (p < 0.05). The micromorphological analysis of the restoration/tooth interfaces showed good adaptation between the composite and tooth substrate in different restorative groups. Conclusions: The ion-releasing capability of the three restorative systems appears to be comparable. The rate of mineral release and diffusion is affected by time and composition. [ABSTRACT FROM AUTHOR]

Background: Previous studies have suggested a potential link between the crown-to-root ratio (CRR) and root morphology in patients with mild chronic periodontitis, which may be associated with tooth mobility. However, these findings have not been thoroughly investigated. Our previous study found that 76% of patients with aggressive periodontitis, particularly those with premolar involvement, exhibited abnormal root morphology, severe alveolar bone loss, and increased tooth mobility, leading to poor clinical outcomes. This study aims to investigate the specific correlations among alveolar bone resorption, root morphology, CRR, and periodontal clinical indicators with premolar mobility in stage III/IV grade C periodontitis patients aged ≤ 35 years. Materials and methods: A total of 1,064 premolars from 151 stage III/IV grade C periodontitis patients aged ≤ 35 years were included in the study. Clinical periodontal parameters and radiographic measurements were recorded. Logistic regression analysis was used to explore the relationships between these indicators and tooth mobility. Results: Significant variations in premolar root lengths were observed, ranging from 6.80 mm to 20.96 mm. Teeth with shorter roots (mean length: 10.22 mm) exhibited grade I mobility with only 28% alveolar bone resorption, whereas those with medium-length (mean length: 12.67 mm) and longer roots (mean length: 14.91 mm) exhibited mobility at 34% and 37% bone resorption, respectively. Regression models incorporating the bone-level CRR, average probing depth, and root length demonstrated strong predictive accuracy for tooth mobility (P < 0.001, AIC = 1700.574). Conclusion: Premolar mobility is influenced by variations in root length, alveolar bone resorption, and probing depth. The bone-level CRR is an effective predictor for assessing tooth mobility, especially when there are differences in root length and alveolar bone resorption. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Extracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice. Methods: Two bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth. Results: Compared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1. Conclusions: The individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth. [ABSTRACT FROM AUTHOR]

PURPOSE. The aim of this study was to investigate microstrains around two non-parallel implant-supported prostheses and different abutment connections and positions under vertical static load using strain gauges. MATERIALS AND METHODS. 4 models simulating the mandibular unilateral free-end were fabricated. 8 implants (4.0 × 10 mm and 5.0 × 10 mm) were inserted in the second premolar, perpendicular to the occlusal plane, and the second molar, tilted at 15°. Four groups were analyzed: engaging and angled abutments (control group), both non-engaging abutments, both screw-and cement-retained prosthesis (SCRP) abutments, and engaging and non-engaging abutments. Strain gauges were placed buccally, lingually, mesially, and distally adjacent to each implant. The restoration was cement-retained in the control group and screw and cement-retained in the rest. Zirconia bridges were fixed on the abutment with NX3, and a 300 N vertical static load was applied. Microstrains were recorded and analyzed. RESULTS. Both non-engaging abutments showed the highest compressive microstrains (-52.975), followed by engaging, angled abutment (-25.239). SCRP-SCRP abutments had the lowest compressive microstrains (-14.505), while the engaging, non-engaging abutments showed tensile microstrains (0.418). Microstrains in SCRP-SCRP and engaging, non-engaging groups were significantly lower than in the control group (a = .05). Premolar areas showed compressive microstrains (-47.06), while molar sites had tensile microstrains (+0.91), with microstrains in premolars being significantly higher than in molar area (a = .05). CONCLUSION. The types of abutment connections and positions may have a potential effect on microstrains at the implant-bone interface. SCRP-SCRP abutments could be an alternative to use in non-parallel implant-supported prostheses when two implants make an angle of no more than 20 degrees. [ABSTRACT FROM AUTHOR]

Background: Early compromised first-permanent-molar (FPM) extraction can adversely affect occlusion. However, the current literature does not provide sufficient support for definitive early extraction outcome. This cohort study aimed to evaluate the pattern of post-FPM extraction spontaneous space closure and its pre-extraction indicators. Methods: Patients of 7–13 years, with compromised FPM at three-tertiary-centers between 2015 and 2019 were retrospectively screened. Pre-extraction indicators were evaluated (extraction location, direction of the second permanent molar (SPM) long-axis, and SPM Demirjian development stage). Spontaneous space closure pattern was evaluated clinically and radiographically using the American Board of Orthodontics (ABO) grading system. Results: In total, 112 FPMs (73-patients) were identified and five (4.5%) of the extraction sites showed favorable combined-ABO-scores. Distal direction of the SPM long-axis in the maxillary arch significantly decreased the relative risk (RR) of having a SPM rotation/alignment ABO score-1 (P = 0.002; RR = 0.64). For the mandibular arch, Demirjian stage D and E significantly decreased the RR of having ABO score-1 for spacing between the SPMs and second premolars (P = 0.029; RR:0.57, P = 0.004; RR:0.53, respectively) and vertical dimension (P = 0.02; RR = 0.53). Conclusions: The direction of the SPM long-axis and its developmental stage are key indicators of the favorable outcome pattern of spontaneous space closure after FPM early extraction. [ABSTRACT FROM AUTHOR]

The purpose of this clinical trail was to assess the clinical behavior of posterior composite restorations supported by a substantial foundation of flowable short fiber-reinforced composite SFRC (everX Flow, GC, Japan) used without proximal surface coverage with particulate filler resin composite (PFC). Seventy patients (20 males, 50 females; mean age: 30 ± 10 years) were randomly enrolled in this trial. Patients received direct restorations of either SFRC covered only on the occlusal surface (1–2 mm) by conventional PFC composite (G-ænial Posterior, GC), or plain conventional PFC composite without fiber-reinforcement, in Class II cavities in premolar and molar vital teeth. One operator made all restorations using one-step, self-etch bonding agent (G-ænial Bond, GC) according to manufacturers' recommendations. Two blinded trained operators evaluated the restorations at baseline, at 6, 12 and 18 months using modified USPHS criteria. Results indicated that, in both groups and at different follow-up intervals, according to evaluated criteria, restorations were rated mostly with best score (Alpha) (p > 0.05). For the marginal integrity after 6 months, a single case in the intervention [increased to 3 (8.8%) after 18 months] and 3 (9.7%) cases of the control group [increased to 4 (12.9%) after 18 months] had Bravo score but with no significant difference (p > 0.05). For color match measured after 6 and 18 months, three (8.8%) cases had Bravo score in the intervention group. The use of flowable SFRC composite without any PFC surface coverage proximally in Class II restorations demonstrated satisfactory clinical outcome throughout the 18-month follow-up. [ABSTRACT FROM AUTHOR]

Purpose: To assess the fracture resistance and failure mode of endodontically treated premolars reconstructed by different preparation approaches: cervical margin relocation (CMR) and crown lengthening (CL) with complete ferrule (CLF) and partial ferrule (CLPF) with three different post and core systems. Materials and Methods: In this in vitro study, 100 maxillary premolars were assigned to the following 10 groups according to their preparation approach and type of post and core system (n = 10): (I) control (intact teeth), (II) prefabricated fiber post (PFP) and composite core with CMR (PFP‐CMR), (III) polyethylene fiber‐reinforced composite (PEFRC) with CMR (PEFRC‐CMR), (IV) casting post (CP) and core with CMR (CP‐CMR), (V) PFP‐CLPF, (VI) PEFRC‐CLPF, (VII) CP‐CLPF, (VIII) PFP‐CLF, (IX) PEFRC‐CLF, and (X) CP‐CLF. After thermomechanical loading, the fracture resistance and failure mode were assessed. Data were analyzed statistically (α = 0.05). Results: In all post and core systems, the CLPF approach had lower fracture resistance than CMR (p < 0.05); CLF showed higher fracture resistance than CLPF only in the PFP system (p = 0.038). In PEFRC and CP systems, the difference between CLF and CLPF was not significant (p > 0.05). No significant difference was found in fracture resistance of different post and core systems with the same preparation approach (p > 0.05). CLPF showed the highest frequency of favorable, and CLF showed the highest frequency of unfavorable fractures. Conclusion: CLPF yielded lower fracture resistance than CMR. The difference in fracture resistance was not significant between CLF and CMR but the frequency of unfavorable fractures was higher in CLF than in other groups. [ABSTRACT FROM AUTHOR]

Background/Objectives: This study aimed to evaluate the effect of ProDesign Logic files 45.01 and 50.01 on apical foramen wear and shape transformation after foraminal enlargement at tooth length (TL) and 1 mm beyond. Methods: Sixty freshly extracted single-rooted lower human premolars teeth were distributed randomly into five groups (n = 12): Group 1 (40.05 WL) (control): No foraminal enlargement, Group 2 (45.01 TL): Specimens underwent foraminal enlargement with 45.01 Prodesign Logic file at TL; Group 3 (45.01 TL + 1): Specimens underwent foraminal enlargement with 45.01 Prodesign Logic file at 1 mm beyond TL; Group 4 (50.01 TL): Specimens underwent foraminal enlargement with 50.01 Prodesign Logic file at TL; Group 5 (50.01 TL + 1): Specimens underwent foraminal enlargement with 50.01 Prodesign Logic file at 1 mm beyond TL. Scanning electron microscopy was used to evaluate apical foramen variations and shape alterations. Data were analyzed by Student's t-test, Kruskal–Wallis, and Mann–Whitney test. Results: Significant differences (p < 0.01) were observed among all tested groups compared to the control group in terms of the average worn area of the apical foramen. Foraminal enlargement led to significant shape transformation, resulting in round-shaped foramina. Conclusion: ProDesign Logic 45.01 and 50.01 files at TL causes notable wear and round-shaped foramina. [ABSTRACT FROM AUTHOR]

Background: Previous deep learning-based studies were mainly conducted on detecting periapical lesions; limited information in classification, such as the periapical index (PAI) scoring system, is available. The study aimed to apply two deep learning models, Faster R-CNN and YOLOv4, in detecting and classifying periapical lesions using the PAI score from periapical radiographs (PR) in three different regions of the dental arch: anterior teeth, premolars, and molars. Methods: Out of 2658 PR selected for the study, 2122 PR were used for training, 268 PR were used for validation and 268 PR were used for testing. The diagnosis made by experienced dentists was used as the reference diagnosis. Results: The Faster R-CNN and YOLOv4 models obtained great sensitivity, specificity, accuracy, and precision for detecting periapical lesions. No clear difference in the performance of both models among these three regions was found. The true prediction of Faster R-CNN was 89%, 83.01% and 91.84% for PAI 3, PAI 4 and PAI 5 lesions, respectively. The corresponding values of YOLOv4 were 68.06%, 50.94%, and 65.31%. Conclusions: Our study demonstrated the potential of YOLOv4 and Faster R-CNN models for detecting and classifying periapical lesions based on the PAI scoring system using periapical radiographs. [ABSTRACT FROM AUTHOR]

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Aim: The main aim of the study was to evaluate tooth position in plaster models of nonorthodontic subjects that have optimal occlusion, using the American Board of Orthodontics (ABO) criteria and comparing it to ABO standards. Methods: Forty nonorthodontic subjects with optimal occlusion were evaluated for teeth positioning with ABO measurement criteria, using the ABO gauge. These measurements were compared to the ABO standards. On the panoramic radiographs of these subjects, distances between the roots of teeth were measured using the digital ruler in Quick CephR. Lateral cephalograms were scanned and digitized into Quick CephR systems to evaluate the skeletal anteroposterior and vertical relationship. Means and standard deviations were calculated for all the variables and compared to ABO standards. Correlations were obtained between attrition and overjet. Correlations were also studied between anteroposterior skeletal relation, vertical skeletal relation, and teeth positioning. In subjects that had accurate age records, the relationship between age and change in buccolingual inclination was evaluated. Results: A significant difference in the mean values for inclination of maxillary and mandibular first bicuspids, second bicuspids, first molars, and second molars as compared to the board criteria was observed. Accuracy of panoramic radiograph to measure root proximity, especially in the cuspid region, is questionable. There was a positive correlation between overjet at the cuspid region and attrition. There was a minimal correlation between age and buccolingual inclination of teeth, indicating only a trend for mandibular second bicuspid to upright with age. Conclusion: The ABO criteria and standards used to evaluate finished orthodontic cases are consistent with naturally occurring optimal dentitions, except for buccolingual inclination of posterior teeth in both maxillary and mandibular arches. [ABSTRACT FROM AUTHOR]

Introduction: The bio-stimulatory effects of low-intensity ultrasound on dental tissues which were clinically introduced in 2004 demonstrated a reduction in root resorption in maxillary premolars subjected to a force level of 50 g. Similar results by applying a torque of 50 g to the maxillary premolars were obtained in 2016; however, the effects of low-intensity pulsed ultrasound (LIPUS) on the presence of high-intensity forces are not yet known. Aim: The purpose of this study was to examine the effects of LIPUS on a sample of 40 patients. Methods: The analysis was conducted by applying two forces to teeth no. 14 and 24, each with an intensity greater than 50 g, and applied at two different points on the coronal surface. Subsequently, LIPUS was applied daily for 20 minutes to tooth no. 14, while tooth no. 24 served as a control. The study lasted for 28 days. Results: Overall, the group treated with LIPUS demonstrated an improvement in the average total volume and percentage of root resorption compared to the control group. The same results emerged for the diameter, depth, and surface of the gaps of resorption. Conclusion: This study showed that it was possible to reduce root resorption in the presence of forces with intensities greater than 50 g. Nevertheless, a longer period of study will make it possible to obtain more rational results as to the effectiveness of low-intensity ultrasound on root resorption induced by orthodontic treatment. [ABSTRACT FROM AUTHOR]

Purpose: To comprehensively analyze the palatal thickness of soft tissues and determine optimal regions for the placement of palatal orthodontic miniscrews. Methods: Cone-beam computed tomography (CBCT) images on the coronal plane were obtained from 60 patients (30 female, 30 male; age range 19–45; mean age 32 ± 11), with 3-mm intervals in the regions of the canine (Ca), first premolar (Pr1), second premolar (Pr2), midpoint between the first and second molars (M1-M2), first molar (M1), second molar (M2) and midpalate. Results: The mucosal thickness measurements between the teeth showed significantly greater thickness in the Ca region at the 3 mm point, in the Pr1 region at the 6 mm point, and in the Pr2 region at the 9 and 12 mm points. At the 9 mm point, the Pr1 region demonstrated greater thickness than the M1-M2 whereas the Pr2 region was thicker than the M1 and M1-M2 regions. At the 12 and 15 mm points, the thickness increased from anterior to posterior: the Pr1 region was thinner than the Pr2, M1, and M2 regions and the Pr2 region was thinner than the M2 region. A schematization was devised for the optimal areas recommended for miniscrews in the palatal region. Conclusion: The mucosal thickness in the palatal region increases from anterior to posterior except the midpalatal region. Based on the results, in terms of soft tissue, the most suitable place for miniscrew placement is 6 mm from the gingival margin of the teeth and in the median portion of the palate. The findings may guide clinicians in choosing the optimal sites for palatal mini-implants. [ABSTRACT FROM AUTHOR]

Background: Infected dentinal tubules are a possible source of bacteria that are responsible for the failure of root canal treatment. Therefore, disinfection of dentinal tubules by increasing the penetration of the irrigation solution is important for success in retreatment cases. This study utilized confocal laser scanning microscopy (CLSM) to assess and compare the impact of XPR, ultrasonic irrigation (UI) and sonic activation (SA) on NaOCl penetration into dentinal tubules following endodontic retreatment. Methods: A total of forty mandibular premolars were enrolled in this investigation. Following root canal preparation up to ProTaper X3 file (30/0.07), root canals were obturated with gutta-percha and bioceramic root canal sealer with single cone technique. The root canal filling materials were removed using ProTaper nickel-titanium rotary retreatment files until the working length was reached. The retreatment procedure was finalized using the ProTaper Next X4 (40/0.06). The teeth were divided into four groups based on the irrigation activation technique: control (conventional needle irrigation), SA, UI and XPR. During the final irrigation procedure, Rhodamine B dye was introduced to 5% NaOCl for visualization via CLSM. Subsequent to image acquisition, the maximum penetration, penetration percentage, and penetration area were calculated. Data were statistically analyzed using the Kruskal-Wallis, Friedman, and Bonferroni Dunn multiple comparison tests through R software (p < 0.05). Results: In the middle third, UI yielded a significantly higher penetration percentage than the control group (p < 0.05). The UI and XPR groups showed increased penetration percentages in the coronal and middle thirds compared with the apical third (P < 0.05). Maximum penetration was notably reduced in the apical third than in comparison with the coronal and middle thirds in all groups (p < 0.05). In the control, SA and XP groups, the penetration area was ranked in descending order as coronal, middle and apical (p < 0.05). Conversely, in the ultrasonic group, the penetration area was significantly lower in the apical third than in the middle and coronal thirds (p < 0.05). Conclusions: UI enhanced the penetration percentage in the middle third of the root compared with that in the control group. XPR and SA showed no significant effect on NaOCl penetration following retreatment. [ABSTRACT FROM AUTHOR]

Background/Objectives: Many older adults living in long-term care (LTC) environments have varying numbers of retained natural teeth. The objective of this study was to assess the disease findings based on tooth type and estimate the role of tooth types in occlusion. Methods: We conducted clinical oral examinations of 276 LTC residents. The disease findings were analyzed for each tooth type and to determine their associations with dementia. Results: In total, 67.8% of the participants had molar teeth. Premolars/canines were often present as residual roots and had caries. Deepened periodontal pockets and higher plaque index (PI) values for molars had odds ratios of 2.5 (95% confidence interval [CI] of 1.59–3.91) and 1.61 (95% CI of 1.29–2.02), respectively. Participants with dementia were more likely to have incisors and premolars/canines in the form of root remnants and higher PI scores for all tooth types (p ≤ 0.01), as well as more deepened periodontal pockets in all teeth (p = 0.029), than those without dementia. The median number of remaining molars per participant was 3 out of a maximum of 12 (95% CI 3.4–4.0); thus, they often lacked occlusal contact. Conclusions: The LTC residents' molars were more prone to periodontal problems, whereas their premolars/canines often had caries or were present in the form of root remnants, especially in the participants with dementia. People's teeth should be treated in an easy-to-maintain way before they move into LTC to enable daily oral hygiene measures and maintain oral health. [ABSTRACT FROM AUTHOR]

Background: Mandibular second premolar agenesis is a common problem in orthodontics and is often treated in conjunction with maxillary counterbalancing extractions. However, in cases without maxillary crowding or dental protrusion, space closure may pose challenges leading to compromised occlusal results or patient profile. Multiple techniques have been described to treat these patients; nevertheless, there is a paucity of data comparing effectiveness of space closure utilizing various anchorage techniques. The goal of this study is to assess the effectiveness of the Herbst device during mandibular molar protraction and compare it to the use of temporary anchorage device (TADs) in patients with mandibular second premolar agenesis. Materials and methods: This retrospective study included 33 patients with mandibular premolar agenesis treated without maxillary extractions. Of these patients, 21 were treated with protraction Herbst devices and 12 with TADs. Changes in molar and incisor positions, skeletal base positions and occlusal plane angulations were assessed on pretreatment (T0) and post-treatment (T1) lateral cephalograms. Scans/photographs at T0 and T1 were used to evaluate canine relationship changes representing anchorage control. Space closure and breakage/failure rates were also compared. Data was analyzed with paired and unpaired t-tests at the significance level of 0.05. Results: Within the Herbst group, changes in mandibular central incisor uprighting and mandibular molar crown angulations were statistically significant. However, no significant differences were noted between the Herbst and TAD groups. Protraction rates as well as overall treatment times were comparable (0.77 mm/month vs. 0.55 mm/month and 3.02 years vs. 2.67 years, respectively). Canine relationships were maintained or improved toward a class I in 82.85% of the Herbst sample, compared to in 66.7% of the TAD sample. Emergency visits occurred in 80.1% of the Herbst group, with cementation failures or appliance breakages as the most common reasons. Conclusion: The Herbst device could be a viable modality in cases with missing mandibular premolars where maximum anterior anchorage is desired, or if patients/parents are resistant to TADs. Furthermore, they could be beneficial in skeletal class II patients with mandibular deficiency who also need molar protraction. However, the increased incidence of emergency visits must be considered when treatment is planned. [ABSTRACT FROM AUTHOR]

Studies comparing transcatheter and surgical aortic valve replacement (TAVR and SAVR) for patients with trileaflet aortic stenosis (AS) have found similar or larger effective orifice area (EOA) for TAVR prostheses. To our knowledge, no studies have compared EOA in patients undergoing TAVR versus SAVR for bicuspid AS. We retrospectively compared prosthetic valvular sizing and predicted EOA for patients with bicuspid AS undergoing TAVR or SAVR at our institution between January 1, 2016, and December 31, 2021. We excluded patients undergoing procedures for indications other than AS and those without a pre-procedural gated Chest CT. Comparisons included demographics, comorbidities, annular size, prosthetic valve size, predicted EOA and prosthesis-patient mismatch (PPM) for TAVR (N = 78) and SAVR (N = 74) cohorts. TAVR patients had smaller pre-procedural annular area (501.7 mm2 vs. 571.8 mm2, p < 0.05) and annular perimeter (80.6 mm vs. 86.5 mm, p < 0.05), but larger mean implanted prosthetic valve size (26.4 mm vs 24.2 mm, p < 0.001) compared to SAVR patients. No differences were observed in predicted EOA, predicted EOA indexed to patient body surface area (EOAi), or predicted PPM grade between TAVR and SAVR groups, including in cohorts sorted by pre-procedural annular size. For bicuspid AS patients undergoing aortic valve replacement, TAVR achieves similar predicted EOA to SAVR. These data support the use of TAVR in selected patients with bicuspid AS and can inform heart team discussions. • TAVR achieves similar predicted EOA to SAVR for patients with bicuspid AS. • Across annular sizes in bicuspid AS, TAVR and SAVR attain similar prosthesis size. • Rates of predicted PPM are not different for TAVR versus SAVR in bicuspid AS. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 57 year old Chinese woman with a rare and potentially new syndrome characterized by palate-bucca fusion, cleft palate, and supernumerary teeth. It describes her unique condition involving a bridge-like fusion tissue from the buccal mucosa to the palate, a cleft in the soft palate, and multiple dental anomalies.

Objectives: This study tests whether (1) premolar topography of extant "prosimians" (strepsirrhines and tarsiers) successfully predicts diet and (2) whether the combination of molar and premolar topography yields higher classification accuracy than using either tooth position in isolation. Materials and Methods: Dental topographic metrics (ariaDNE, relief index, and orientation patch count rotated) were calculated for 118 individual matched‐pairs of mandibular fourth premolars (P4) and second molars (M2). The sample represents 7 families and 22 genera. Tooth variables were analyzed in isolation (P4 only; M2 only), together (P4 and M2), and combined (PC1 scores of bivariate principal component analyses of P4 and M2 for each metric). Discriminant function analyses were conducted with and without a measure of size (two‐dimensional surface area). Results: When using topography only, "prosimian" P4 shape predicts diet with a success rate that is slightly higher than that of M2 shape. When absolute size is included, premolars and molars perform comparably well. Including both premolar and molar topography (separately or combined) improves classification accuracy for every analysis beyond considering either in isolation. Classification accuracy is highest when premolar and molar topography and size are included. Discussion: Our findings indicate that molar teeth incompletely summarize the functional requirements of oral food breakdown for a given diet, and that the mechanism selecting for premolar form is more varied than what is expressed by molar teeth. Finally, our findings suggest that fossil P4s (in isolation or with the M2) can be used for meaningful dietary reconstruction of extinct primates. Research Highlights: "Prosimian" premolar shape predicts diet with similar accuracy to molarsCombining premolar and molar variables improves dietary classificationPremolar shape reflects functional demands that may contrast with those on molars shape [ABSTRACT FROM AUTHOR]

Aim: This study aimed to identify the risk factors for gingival invagination during orthodontic treatment after premolar extraction. Materials and Methods: The medical records of 135 patients who had undergone interdental space closure after premolar extraction were collected, and cone beam computed tomography was performed to determine the presence of gingival invagination. The risk factors were examined using mixed‐effects models and generalized propensity score weighting (GPSW) to develop a predictive model. Results: Univariate analysis revealed that the extraction site, buccal bone thickness 4 mm apical to the cemento‐enamel junction (MB1), mid‐root buccal bone thickness (MB2) and vertical skeletal relationships were related to gingival invagination (p <.05). Furthermore, a subsequent multivariable mixed‐effects model analysis indicated a significantly increased risk of gingival invagination at MB1 < 1 mm (p <.001; odds ratio [ORMB1≤0.5mm] = 29.304; 95% confidence interval [CI]: 8.986–93.807; OR0.5

The "Diahot Tooth" is an isolated postcanine tooth of a large herbivorous mammal, discovered in the Diahot region of northern New Caledonia in 1875. Most authors have identified it as an upper premolar of a rhinocerotid, but an alternative proposal is that it belongs to a diprotodontoid marsupial that has been named Zygomaturus diahotensis. Either possibility raises biogeographical difficulties, because New Caledonia has been isolated from other major landmasses for 80 million years, and neither rhinocerotids nor diprodotontoids appear to be good candidates for such a long-distance overwater dispersal event. Here, we present a novel interpretation of the affinities and origin of the Diahot Tooth, based on qualitative study of its preserved morphology and quantitative phylogenetic analyses that include both rhinocerotids and diprotodontoids. We show that the Diahot Tooth most closely resembles the first deciduous premolar of Western Eurasian Miocene teleoceratine rhinocerotid Brachypotherium brachypus, with the few discrepancies relating to traits that are known to be variable in B. brachypus. Our phylogenetic analyses also support this relationship. The preservation of the Diahot Tooth closely resembles that of B. brachypus teeth from the "Faluns Sea" of the Loire basin, and we propose that the New Caledonian specimen originated there and was taken to New Caledonia by a European colonist during the mid-19th century, where it was lost, rediscovered, and incorrectly assumed to be autochthonous. [ABSTRACT FROM AUTHOR]

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A patient presented desiring to improve her esthetics and reduce masseter muscle pain prior to her upcoming wedding. Although the patient had a full-mouth rehabilitation with porcelain restorations at age 16, she presented with extensive overjet, unbalanced occlusion, and lack of contact from premolar to premolar. The clinician was faced with the challenge of determining the best course of treatment. After completing thorough record-taking and a detailed analysis following a systematic approach, the clinician developed a facially driven treatment plan that was carried out over eight phases. The patient's existing crowns were replaced at a reduced vertical dimension of occlusion, esthetics were enhanced, muscle pain was relieved, and her goals were achieved. [ABSTRACT FROM AUTHOR]

Tooth transposition is the positional interchange of two adjacent teeth, which may be incomplete or complete. The root apex may remain in a normal position despite a severely displaced crown. The aim of this paper is to provide a literature review on the incidence, aetiology and treatment options for pseudo-transposed mandibular incisors. A case series is also presented highlighting the various management techniques that have been utilised in treating five cases of pseudo-transposed mandibular lateral incisors. [ABSTRACT FROM AUTHOR]

This paper describes the orthodontic treatment of two cases that were successful in winning the William Houston Gold Medal at the Membership in Orthodontics Examinations of the Royal College of Surgeons of Edinburgh in 2022. Both cases discuss the management of palatally impacted maxillary canines and treatment was initiated during the emerging COVID-19 crisis and completed over a 27-month period. The first case describes the management of a 15-year-old female with a Class II division 1 incisor relationship complicated by a palatally impacted upper left canine, moderate upper and lower arch crowding, and a lower centreline discrepancy with an associated right lateral displacement on closure. Treatment involved open surgical exposure of the impacted canine, a quad helix appliance, premolar extractions, and upper and lower fixed appliances. The second case describes the management of a 14-year-old female with a Class III incisor relationship complicated by bilaterally impacted maxillary canines, impeded eruption of the lower right second molar, moderate lower and severe upper arch crowding, and an upper centreline discrepancy. These case reports aim to demonstrate the high standards of care achieved by Orthodontic Specialty Trainee Registrars in the UK and provide aspirational standards for future trainees. [ABSTRACT FROM AUTHOR]

The article examines the outcomes of low-risk patients with bicuspid aortic valves undergoing transcatheter aortic valve replacement (TAVR), highlighting favorable results at three years with low rates of death and disabling stroke. Topics discussed include the successful use of the Evolut valve, the challenges associated with bicuspid aortic valve anatomy, and the need for careful patient selection and long-term data to guide treatment decisions.

Objective To evaluate and compare the root canal morphology of mandibular premolars in Saudi and Sudanese subpopulations and between males and females within each group using cone-beam computed tomography (CBCT). Materials and Methods A cross-sectional study was done between May 2022 and July 2023. Six hundred premolars from Saudi and Sudanese subpopulations were evaluated using CBCT for their number of roots, type of root canal configuration based on Vertucci's classification, and average canal length measured from the buccal cusp tip to the root end. Statistical Analysis Statistical comparisons were made between males and females within each subpopulation and the two subpopulations using the chi-square test for root number and type of root canal configuration and an independent sample t -test for the canal length. Results Most mandibular premolars in both subpopulations had a single root, with type I root canal configuration. However, Sudanese showed various canal configurations (I, II, III, IV, and V) compared with Saudis, which was statistically significant in the first canal of the first mandibular premolar (p < 0.05). Also, there were statistically significant differences in canal length between Saudi males and females (p < 0.05) and between Saudis and Sudanese (p < 0.05) in the first and second premolars. Conclusion Although most mandibular premolars in Saudi and Sudanese subpopulations exhibited a single root and type I canal configuration, variations exist between and within the groups, highlighting ethnic and gender differences and emphasizing the need for dentists' attention. [ABSTRACT FROM AUTHOR]