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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]

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]

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]

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]

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]

Introduction: Erbium‐doped yttrium‐aluminum‐garnet (Er:YAG) laser debonding of zirconia and lithium disilicate restorations is increasingly used for a range of clinical applications. Using rotary instruments to remove such restorations for any purpose has proven to be challenging. Erbium laser has been reported to be a conservative method for removing ceramic restorations. There is little data in the literature about the effect of adhesive resin cement type on the debonding time of the ceramic restoration using the Er:YAG laser. Objectives: To evaluate and compare the time required for the Er:YAG laser to debond zirconia and lithium disilicate crowns bonded with a 2‐ and 1‐bottle adhesive resin cement systems. Materials and Methods: Forty extracted premolar teeth were prepared and scanned for milled 40 CAD/CAM crowns. Teeth were randomly assigned into groups (n = 10 per group): 3 mol% yttria‐partially stabilized zirconia crowns 3Y‐PSZ (G1a) bonded with Panavia™ V5 (2‐bottle adhesive resin cement), Zirconia 3Y‐PSZ crowns (G1b) bonded with RelyX™ Ultimate (1‐bottle adhesive resin cement), and for the lithium disilicate crowns bonded with the two types of cements (G2a, G2b). Each specimen was irradiated with an Er:YAG laser at 335 mJ, 15 Hz, 5.0 W, and 50‐ms pulse duration (super short pulse mode). The irradiation time required for crowns to be successfully debonded was recorded for each specimen. Data were statistically analyzed using ANOVA and Tukey HSD post‐hoc test (p < 0.05), at the 95 percent level of confidence. The intaglio surface of the debonded crown was analyzed using scanning electron microscopy (SEM). Results: The mean ± standard deviation times needed for crown debonding were 5.75 ± 2.00 min for the G1a group, 4.79 ± 1.20 min for group G1b, 1.69 ± 0.49 min for group G2a, and 1.12 ± 0.17 for group G2b. There was no statistically significant difference in debonding time between the 2‐ and 1‐ bottle adhesive resin cement within the groups G1a and b (p = 0.2914), or between groups G2a b (p = 0.7116). A statistically significant difference (p < 0.05) was found between groups G1a and G2a and b and between groups G1b and G2a and b were SEM analysis showed no changes in the microstructure of the ceramic surface after Er:YAG laser irradiation. Conclusion: Zirconia and lithium disilicate restorations can be debonded using Er:YAG lasers in a safe and efficient manner. There is no significant difference in the debonding time between the 2‐ and 1‐ bottle adhesive resin cement systems used in this study. Clinical Significance: Retrieving zirconia and lithium disilicate ceramics can be a challenging process when using diamond rotary instruments. ER:YAG lasers may efficiently debond these ceramics from the tooth structure, independent of the bonding process used for bonding them. [ABSTRACT FROM AUTHOR]

Objective: Orthodontic treatment often involves four first premolar extractions. There is concern that the retraction of the anterior teeth due to extraction of first premolars may constrict tongue space and will reduce oral cavity and oropharynx space. Constricted airways are often associated with sleep disordered breathing (SDB) and sleep disruption. The aim of this study was to determine if there is an association of SDB factors with the absence of first premolars. Methods: A cross‐sectional study was conducted using National Health and Nutrition Examination Survey (NHANES) 2017‐March 2020 data on participants, aged 18–65 years (n = 4742). Variables of interest included self‐reports of SDB (symptoms of disrupted sleep such as snoring, snorting, daytime sleepiness, and inappropriate number of hours of sleep). Data for the presence/absence of first premolars were gathered from the oral examination section of NHANES. An assumption was made that absence of four first premolars in dentate participants indicated extractions for orthodontic treatment. Data analyses were conducted with Rao Scott chi squared test. Results: There were no significant associations of SDB and symptoms of disrupted sleep associated with the absence of four first premolars in dentate participants. Conclusion: Concerns of the impact of first premolar extractions on SDB were not supported with this study. [ABSTRACT FROM AUTHOR]

To evaluate the comparative effects of air-turbine and electric handpieces on dental preparation, 60 premolars were categorized into four groups, each comprising 15 specimens, based on the preparation method employed: air-turbine handpiece (Group A), and electric handpiece set at rotational speeds of 200,000rpm (Group B), 50,000rpm (Group C), and 20,000rpm (Group D). Analysis revealed no statistically significant difference in the surface roughness of the preparations across the four groups (p>0.05). Similarly, no significant variance was observed in fracture resistance among the groups (p>0.05). However, a notable distinction was detected in the degree of microleakage following the aging test (p<0.05), with veneers prepared using the electric handpiece at 200,000rpm demonstrating the lowest average microleakage. It is noteworthy that the surface roughness of the preparations and the veneers’ fracture resistance remained unaffected by the variations in preparation method. [ABSTRACT FROM AUTHOR]

In recent years, dental implants have become a trend in the treatment of human patients with missing teeth, which may also be an acceptable method for companion animal dentistry. However, there is a gap challenge in determining appropriate implant sizes for different dog breeds and human. In this study, we utilized skull computed tomography data to create three-dimensional models of the mandibles of dogs in different sizes. Subsequently, implants of various sizes were designed and subjected to biomechanical finite element analysis to determine the optimal implant size. Regression models were developed, exploring the relationship between the average weight of dogs and the size of premolar implants. Our results illustrated that the regression equations for mean body weight (x, kg) and second premolar (PM2), third premolar (PM3), and fourth premolar (PM4) implant length (y, mm) in dogs were: y = 0.2785x + 7.8209, y = 0.2544x + 8.9285, and y = 0.2668x + 10.652, respectively; the premolar implant diameter (mm) y = 0.0454x + 3.3506, which may provide a reference for determine suitable clinical implant sizes for dogs. [ABSTRACT FROM AUTHOR]

Palaeotragus is a common genus of the Giraffidae that was widely distributed in the Neogene strata of Eurasia. Early studies usually placed small giraffids in the Palaeotragus clade, leading to considerable controversy over the validity and systematic classification of this genus. Palaeotragus microdon and Palaeotragus cf. coelophrys are two representative species of Palaeotragus in China, their dental specimens are mainly distinguished by size, causing problems in their actual identification. In this study, several mandibles of a small giraffid found in Linxia Basin, Gansu Province, China (MN 10–13), are studied and identified as Palaeotragus cf. coelophrys. Based on a detailed comparison, the size and morphological variability of the Chinese Palaeotragus dental material are discussed, as well as the validity of the two species and the validity of other Eurasian Palaeotragus. This study reveals that the Chinese Palaeotragus has a continuous sequence of size variability and premolar features, which is insufficient to separate the mandible of the two species. In addition, the type species P. rouenii can be clearly distinguished from the Chinese Palaeotragus by the relatively long lower premolar row, possibly due to the difference in feeding habits. The holotype of P. coelophrys is closely related to Chinese Palaeotragus, while the P. coelophrys mandible from Maragheh (MMTT37 2517) should belong to different species. [ABSTRACT FROM AUTHOR]

Objective: Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in‐office bleaching protocols with different application times. Materials and Method s : Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV–Vis spectrophotometry. Statistical analysis included one‐way ANOVA, Tukey's, and Dunnett's tests (α = 0.05). Results: All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05). Conclusion: A simplified 1 × 30‐min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth. Clinical Significance: This study suggests that an in‐office dental bleaching protocol using a 1 × 30‐min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration. [ABSTRACT FROM AUTHOR]

Objectives: Aim of this study was to assess survival rates, radiographic, and pink esthetic outcomes of a bone‐level‐tapered (BLT) implant following immediate or early implant placement. Materials and Methods: Patients in need of tooth extraction and one implant in the anterior or premolar area were recruited in five centers. Patients were randomly assigned to the immediate or early placement protocol. Implants were restored with all‐ceramic crowns cemented to titanium‐base‐abutments. Radiographic bone levels, implant stability quotient (ISQ), and pink esthetic outcomes were assessed. Data were analyzed descriptively. Level of significance was set at 0.05. Differences between groups were tested using Wilcoxon‐signed‐rank and Mann–Whitney‐U test as nonparametric tests. Results: A total of 60 patients received 60 BLT implants (Institut Straumann). At 12‐months, 59 implants (98.3%) were osseointegrated. The mean distance from implant shoulder to first bone‐to‐implant contact was 0.15 ± 0.59 mm without significant differences between the groups. Median ISQ values increased from 75.5 to 78.5. A mean buccal recession of 0.1 ± 0.70 mm occurred with no difference between groups. The mean papilla height gain in both groups was 0.5 ± 1.47 mm mesially and 0.4 ± 1.36 mm distally. Conclusions: After 1 year, immediately and early placed BLT implants exhibit similar bone level changes, ISQ values, and pink esthetic outcomes. Clinical Significance: The present research contributes to the knowledge on clinical outcomes of immediately and early placed BLT implants restored with buccally microveneered ceramic single crowns out of two different ceramic materials. The research shows that similar esthetic and radiographic outcomes can be reached by means of immediate implant placement compared to the conventional early placement protocol. The improvement of esthetic soft‐tissue parameters over time was shown for both implant placement protocols. [ABSTRACT FROM AUTHOR]

While root canal anatomy in Middle Eastern populations is well‐studied, research on isthmi in mandibular permanent teeth from this region is limited. This retrospective study used cone‐beam computed tomography (CBCT) to examine isthmi prevalence and location, as well as root canal morphologies (per Vertucci's classification) in mandibular permanent teeth from a subpopulation in Ardabil, Iran. The study is aimed at enhancing our understanding of dental anatomical variations in Middle Eastern populations. A total of 3566 teeth from 384 CBCT scans were evaluated in this retrospective study. Mandibular teeth were evaluated on sagittal, coronal, and axial sections regarding the presence of isthmus and root morphology (Vertucci's classification). CBCT scans of 197 males (51.3%) and 187 females (48.7%) were evaluated, with a mean age of 41.1 ± 11.4 years. Isthmi were most prevalent in molar mesial roots, typically located in the middle third for anterior teeth and first premolars and cervical third for posterior teeth. While gender did not play a significant role, the presence of an isthmus in the mesial root of the left second molars was associated with a younger mean patient age (p < 0.05). Root morphology varied across tooth types. Central and lateral incisors predominantly showed Vertucci's Types I and III. Canines and premolars were mostly Type I, with some variation. Molar mesial roots frequently exhibited Types IV and II, while distal roots were predominantly Type I. Statistically significant differences were found between morphology and gender in the first left premolar (Type I more common in women; Type V in men; p < 0.001) and in the right canine (Type I more prevalent in men; Types III and V more prevalent in women; p < 0.001). The results revealed wide variations in root canal morphology and a relatively high prevalence of isthmi in the study population. Our findings suggest a potential difference in tooth anatomy based on sex and a relationship between age and the presence of isthmi. [ABSTRACT FROM AUTHOR]

Recent advancements in dentistry have introduced new light-curing units such as 1-second and 5-second LED curing lights to orthodontics. We aimed to evaluate the shear bond strength and Adhesive Remnant Index (ARI) of stainless-steel orthodontic brackets cured with 1-second, and 5-second LED curing lights. Ninety human extracted upper premolars were selected based on the inclusion and exclusion criteria. The selected teeth were randomly divided into 2 groups - Group I and Group II. In Group I, the teeth were bonded with Standard pre-adjusted edgewise upper premolar brackets (Orthox, JJ Orthodontics) using Transbond XT and cured with Woodpecker iLED 1-second curing light. In Group II, the same brackets and composite were used to bond and light-cure with 5-seconds Woodpecker LED-D unit. The shear bond strength and the Adhesive Remnant Index (ARI) of brackets in both groups were evaluated. Student t-test was used for the statistical analysis of the data. In Group-I (1-second LED curing light), the shear bond strength was 6.62 MPa, whereas it was 10.32 MPa in group II (5-second LED curing light). A highly significant difference was observed in the shear bond strength between the groups. The ARI scores further revealed that the 5-second curing light resulted in a safer failure mode, with adhesive remaining mostly on the bracket. We found that the 5-second Woodpecker LED-D curing light demonstrated higher shear bond strength compared to the 1-second iLED curing light, although both sets of bond strength values are clinically acceptable. [ABSTRACT FROM AUTHOR]

Objective: White spot lesions are one of the most common problem during and after orthodontic therapy. The present study was accomplished to evaluate the ability of Magnesium gel at different concentration and diode laser in combination compared with commercially available 1.23%APF in color restoring of WSL on permanent teeth. Materials and Methods: In this in vitro study, 42 human caries-free premolar teeth were randomely divided into 6 experimental groups: Group A: Control (artificial saliva), Group B: 0.5%MgCl2 gel, Group C: 1%MgCl2 gel, Group D: 0.5%MgCl2 gel and Diode laser, Group E: 1%MgCl2 gel and Diode laser and Group F: 1.23%APF. The difference between the displayed color and the original color standard (ΔE) was assessed by colorimeter. The surface topography of teeth samples from each tested group was examined by a SEM. Collected data were investigated using one-way ANOVA followed by Duncan post hoc test at p ≤ 0.05. Result: A significant difference in (ΔE) was noticed among groups (p= 0.006). Group (B) showed the lowest ΔE value (9.4±1.6), followed by group (D) (10.2±1.1), group (F) (10.4±2.6), group (A) (11.6±1.3), group (C) (12.9 ±2.3) and group (E) (13.2±1.3). Conclusion: 0.5% magnesium gel is as 1.23% APF gel in color restoring of white spot lesion. No synergistic effect between materials and diode laser. [ABSTRACT FROM AUTHOR]

To evaluate, in a prospective clinical study over 5 years with ex vivo 3D profilometry analyses, the intraoral wear of Polymer-Infiltrated Ceramic Network (PICN) CAD-CAM composite restorations used in severe tooth wear treatment with the One-Step No-Prep technique. 192 PICN (Vita Enamic) restorations on molars and premolars were included in a prospective clinical study involving patients treated according to the One-step No-prep protocol (n = 7). All patients showed clinical signs of bruxism. Replicas of restorations on molars and premolars were realized at each evaluation time (baseline and then every year up to 5 years) and scanned to perform 3D profilometry. Baseline and recall scans were superimposed with Geomagic Control software. The mean material wear was calculated for the full occlusal area (FOA) and for the occlusal contact area (OCA), respectively. Clinical evaluation of restorations was performed at recall. At 5 years, the estimated mean material wear for FOA was inferior to the accuracy threshold of the profilometry measurement chain. For OCA, the estimated mean wear of the material was – 27.97 µm. This material wear was shown to be significantly influenced by time (p < 0.0001) and patient (p = 0.026), while the type of tooth (molar or premolar) had no influence. At 5 years, the survival and the success rates of restorations were 99.48% and 90.62%, respectively. The PICN material exhibits a low wear process in the treatment of severe tooth wear despite the presence of clinical signs of bruxism, and it constitutes a suitable material for the One-step No-prep technique. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the suitability of a Doppler ultrasound probe in detecting the greater palatine artery or its greater branches non‐invasively. Materials and Methods: The palatal mucosa of 108 participants (median age 34 years, 51 female) was systematically divided into transversal sectors, each aligning with the positions of the upper molars (M), premolars (P) and canine teeth (C), aiming to facilitate precise and consistent localization of the detected palatal blood vessel across different patients. Blood flow of the palatal blood vessels, presumably, was located by scanning the palatal vault bilaterally using an 8‐MHz ultrasound probe linked to a transducer. The distance to the corresponding tooth was measured using a millimetre‐scale periodontal probe. Results: Within the regions of M2 to P1, the ultrasound transducer gave a delimitable acoustic pulse signal in 80%–98% of all measurements. The measured median distances between the determined position of the artery and the corresponding teeth ranged from 13 to 15 mm, with smaller distances in the anterior region. In several sectors, the distance was significantly higher for men (C: p =.048; P1: p =.041, M1: p <.01; M2: p =.034). Conclusions: Use of the Doppler ultrasound transducer might be a promising approach to non‐invasively detect relevant palatine blood vessels preoperatively. It, therefore, might have the potential to reduce the risk of accidental injury during palatal surgery. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present paper is to describe a systematic and detailed protocol for rapid orthodontic extrusion, and to summarize the main results of this protocol in terms of migration of dental, hard and soft tissues, for 10 cases. Clinical considerations: The working design was to apply a protocol lasting 4 weeks of active phase with intense forces (greater than 300 g), perform weekly the circumferential supra‐crestal fiberotomy procedure associated with root‐planning, follow up with a passive stabilization phase of another 4 weeks and evaluate the results. Conclusions: We believe that despite the partial migration of periodontal tissue, the defined protocol we used is, for simplicity of application, brevity of treatment and results, a viable alternative to the surgical technique of clinical crown lengthening in those cases where it is necessary to have more dental tissue exposed for restorative and prosthetic purposes. [ABSTRACT FROM AUTHOR]

Background: Cervical external root resorption (CERR) is not a common occurrence, but can result in a hopeless tooth prognosis. Its etiology is poorly understood and its management can be challenging. The present case report describes the late presentation and management of CERR at both maxillary first premolar teeth following connective tissue grafting (CTG) procedures including use of citric acid as a chemical root surface conditioner. Methods and Results: A 55‐year‐old female was diagnosed with bilateral external cervical root resorption of both maxillary first premolar teeth 28 years after CTG procedures that had included the use of citric acid root conditioning. As both teeth were asymptomatic, the patient opted for repair of the lesions via full‐thickness flap elevation, meticulous removal of all granulation tissue, and restoration of the lesions with a resin‐modified glass ionomer. A 2‐year follow‐up has been completed with no significant complications to report. Conclusions: CERR usually develops asymptomatically and is found by chance in radiographs. Its etiology is unclear, but may appear some years after soft tissue grafting to manage gingival recession. Early detection is key to be able to repair the lesions with minimal intervention. [ABSTRACT FROM AUTHOR]

The severity of pulpitis is a crucial factor in determining the suitable treatment. There are no clear objective indicators to assess the stage of pulp inflammation that could be used in clinical practice. The change in blood pH of the pulp during the inflammatory phase could hypothetically serve as an indicator of the pulp inflammation severity. The aim of this study was to assess the pH values in the pulpal blood of mature teeth in patients with symptomatic pulpitis, in comparison with the healthy controls. The study included patients with symptoms of pulpitis in premolar or molar teeth (Test group; n = 24, mean age 36.04, SD 7.10), and healthy controls (Control group, n = 6, mean age 24.5, SD 5.94) referred for extraction of premolars or third molars, for orthodontic reasons. The pulpal blood was taken at the opening of the endodontic access cavity, and the pH value was measured in both groups. Statistical analysis was performed using the SPSS 27.0 program with a significance level of p ≤ 0.05. The Mann–Whitney test for dependent samples was performed to evaluate the statistical difference between the groups. The patients with symptomatic pulpitis had significantly decreased pulpal blood pH compared to the healthy controls (p ≤ 0.05). The mean pulpal blood pH was 7.27 (SD 0.06) and 7.40 (SD 0.02) in Test and Control groups, respectively. In the Test group, the pulpal blood pH values were significantly lower in the patients who had symptoms for 3 days or more (7.25, SD 0.05) than in those who had symptoms for up to 3 days (7.33, SD 0.03) (p < 0.001). The pH value of the pulpal blood gradually declines in cases of symptomatic pulpitis, along with increasing duration of the symptoms. [ABSTRACT FROM AUTHOR]

Background: Large horizontal maxillary overjet (overjet) is associated with reduced bite force (BF) and number of contacts, which influence the chewing effectivity (CE). Oral health, oro‐facial function (OF) and malocclusion have great impact on psychological well‐being and quality of life (QoL). Objectives: The aims of the study were to examine OF, temporomandibular disorders (TMD), BF, CE, QoL and well‐being in children and adolescents with large overjet. Methods: The study was a case–control study including healthy children with large overjet in the study group compared to a control group of healthy children with neutral occlusion, all 9–14 years old. OF was examined by use of Nordic Orofacial Test‐Screening (NOT‐S), Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and registration of morphological and functional occlusion. QoL and well‐being were examined using KIDSCREEN‐10 and Strengths and Difficulties Questionnaire. Results: The study and control groups included 37 and 32 participants, respectively. Significantly increased NOT‐S score (p <.001) and reduced BF (p =.011), numbers of contacts (p <.001) and CE (p =.005) were found in the study group. BF, numbers of contacts and CE were negatively associated with erupting canines and premolars. No significant difference was found in age, gender, dental eruption, TMD diagnosis or QoL between the groups. Significantly increased emotional symptoms (p =.007), hyperactivity (p =.043) and total difficulties score (p =.009) were found in the study group. Conclusion: The study group showed higher NOT‐S score and reduced BF, number of contacts and CE. No difference in QoL were found between the groups, although reduced well‐being and increased emotional symptoms, hyperactivity and total difficulties were found in the study group. [ABSTRACT FROM AUTHOR]

Introduction: Orthodontic treatment of severe Bi-maxillary protrusion cases involves extractions of all four premolars to provide space for anterior teeth retraction. Over the years different methods of retraction have been developed for individual tooth retraction and en-masse anterior teeth retraction utilising different types of mechanics for retraction purposes. Anchorage consideration has been a problem because of anchor loss, but it has been overcome by utilising absolute anchorage with Temporary Anchorage Devices (TAD). Need for the study: The TAD devices mini plates and miniscrew have been Known for providing absolute anchorage for retraction purposes but there has been limited evidence to prove which TAD device is better in terms of time taken for retraction and external root resorption. Therefore, the present clinical study aims to determine the superior treatment method using the two devices based on duration in terms of time taken and amount of retraction achieved in the specified time. Aim: Evaluation and comparison of the effectiveness of miniplate and mini-screw for retraction of anterior teeth in severe bimaxillary protrusion cases with extraction of Ist bicuspids. Materials and Methods: A split-mouth randomised controlled trial will be carried out in the Department of Orthodontics and Dentofacial Orthopedics, Sharad Pawar Dental College and Hospital, Sawangi, Wardha, from October 2024 to March 2026 with a total of 11 subjects. The sample will be selected from the Outpatient Department based on the study's inclusion and exclusion criteria. Informed written consent will be gathered from all participants. The patient sample will be divided into two groups: Group-A: will receive a mini screw (control group) and Group-B: will receive a mini-plate (experimental group). The statistical analysis for comparing the en-mass rate of retraction of anterior teeth (mm) in the allocated groups will be done using the Mann-Whitney test, and student's t-test, with the significance level set at 5%. [ABSTRACT FROM AUTHOR]

Background: The aim of this investigation was to assess the apical extrusion potential of sodium hypochlorite (NaOCl) in agarose-embedded mandibular first premolars employing four final agitation procedures. Methods: Based on CBCT confirmation of single oval-shaped canals, one hundred extracted mandibular first premolars were chosen. Using 5.25% NaOCl, the teeth were prepared using the XP Endo Shaper and divided into experimental and control groups. The following were the experimental groups: Group 1 comprised the XP-Endo Finisher, Group 2 the Ultrasonic Activation, Group 3 the Gentle File Finisher Brush, and Group 4 the 27-gauge side-vented needle. To test extrusion, the teeth were placed in a 0.2% agarose gel that contained the pH-sensitive dye m-cresol purple, allowing pixel quantification via ImageJ software (version 1.54i). Results: The XP Endo Finisher featured the most pixels, depicting higher apical extrusion (p < 0.01), followed by the side-vented needle, Gentle File Finisher Brush, and PUI, while the Control Group endured no extrusion. Conclusions: The effective irrigation method for root canal therapy is critical, especially in situations of open apices, resorption, or perforation. According to in vitro experiments, the XP-Endo Finisher has the maximum sodium hypochlorite extrusion, which is determined by parameters such as apical preparation size and irrigation system. [ABSTRACT FROM AUTHOR]

Simple Summary: Cheek teeth extractions are a laborious procedure. A minimally invasive transbucal screw extraction technique has been described. This technique requires several mallet strikes to disrupt the periodontal ligament to loosen the affected tooth. The objective of this study is to provide evidence that the use of a corkscrew-like mechanism is effective in completing cheek tooth extraction in standing sedated horses without the use of a mallet. The instruments and methodology described here can help equine practitioners to improve dental screw extractions. Further studies are needed to refine the instruments and procedures as well as evaluate both intraoperative and postoperative complications. Several tooth extraction techniques are described in equine literature, and oral extraction techniques in standing sedated horses are popular among equine practitioners. The objectives of this study were to develop the corkscrew technique for cheek tooth extraction (CSET) in equine cadaver heads and evaluate this technique in clinical cases. We hypothesized that the CSET could be performed safely to extract cheek teeth in standing sedated horses. First, the CSET was attempted and developed in eight equine cadaver heads. Second, the CSET was performed in clinical cases between 2016 and 2020, and the following information was recorded: diagnosis, affected tooth, procedure duration, intraoperative difficulties, tooth size, postoperative complications, medication, hospitalization time, and 1-year follow-up. Sixteen CSET procedures were performed in eight equine skulls with a 75% success rate. In 24 clinical cases, 25 CSET procedures were attempted to extract 22 superior and 3 inferior cheek teeth. CSET was successful in 76% of procedures. Fractures of the tooth and stripping of screw threads were the major complications that led to the failure of CSET. CSET is a viable and safe technique to extract cheek teeth in standing sedated horses. Longitudinal drilling is a must for this technique to be successful. [ABSTRACT FROM AUTHOR]

Aim of this prospective study was to assess full mouth rehabilitation of severe tooth wear patients using minimally invasive CAD/CAM resin-based composite (RBC) restorations and direct veneers by evaluating restoration survival up to 5.5-years. Twenty-two patients with generalized severe tooth wear with functional and/or esthetic problems were included. Following minimally invasive preparation, CAD/CAM RBC restorations (LAVA Ultimate,3M) were adhesively luted, direct RBC veneers (Filtek Supreme XTE, 3M) were applied in the aesthetic region. Patients were recalled after 1m,1y,3y,5y and seen in between recalls by their general dentists or at the clinical study center if complaints occurred. Failures were categorized as F1 (severe deficiencies requiring replacement/extraction), F2 (localized deficiencies requiring re-cementation/repair) and F3 (small chippings requiring refurbishment/monitoring). Survival of indirect restorations was evaluated using lifetables and Kaplan-Meier-graphs, distinguishing between failure categories and tooth type (front teeth=FT, premolars=PM, molars=M). F1 + F2 and F1 + F2 + F3 failures were analyzed using Cox regression on the variables tooth type/ location, age, gender and VDO increase (p < 0.05). 568 indirect restorations and 200 direct veneers in 21 patients evaluated for up to 5.5-years. For indirect restorations, 96 failures were recorded (F1:6;F2:41;F3:49) and annual failure rates were 0.29%(FT), 1.56%(PM), 2.93%(M) for F1 +F2 and 0.53%(FT), 2.42%(PM), 6.11%(M) for F1 + F2 + F3. Reasons for failure were chipping fracture (48), adhesive fracture (32), complete debonding (7), caries (4), endodontic treatment (1) and reasons unknown (documentation general dentists, 4). Molar tooth type had a statistically significantly increased probability of failure compared with front teeth and premolars for F1 + F2 + F3 (p < 0.006). Direct veneer restorations showed 18 failures (F1:2;F2:9;F3:7). Minimally invasive CAD/CAM RBC restorations combined with direct RBC veneers showed an acceptable clinical mid-term survival for restorative rehabilitation of severely worn dentitions. • Minimal-invasive CAD/CAM RBC restorations can protect severely worn dentitions. • Restorations on molars exhibited higher failure probability than those on other tooth types. • Refurbishment and repair of RBC restorations should be considered before replacement. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of direct restorations using unidirectional glass fiber orientations and a short-fiber-reinforced composite (SFRC) on the fracture resistance of endodontically treated premolars with mesio-occluso-distal cavities. Ninety double-rooted premolars were selected. Fifteen teeth were left intact/as a control group. The endodontic treatment and cavity preparations of seventy-five teeth were performed and divided into five experimental groups: Resin composite (RC), modified transfixed technique + RC, circumferential technique + RC, cavity floor technique + RC, and SFRC + RC. All teeth were fractured under oblique static loading at a 30° angle using a universal testing machine. The fracture patterns were observed and classified. Data were analyzed with one-way analysis of variance, Pearson chi-square, and Tukey HSD post hoc tests (p = 0.05). The highest fracture strength values were obtained in intact teeth (599.336 N), followed by modified transfixed + RC treated teeth (496.58 N), SFRC + RC treated teeth (469.62 N), RC (443.51 N), circumferential + RC treated teeth (442.835 N), and cavity floor + RC treated teeth (404.623 N) (p < 0.05). There was no significant difference between the RC and the circumferential technique + RC (p > 0.05). Unrepairable fractures were observed at low rates (20%) in the modified transfixed + RC and SFRC + RC teeth, and at higher rates in RC (73.3%), cavity floor + RC (60%), and circumferential + RC (80%) teeth. The application of an SFRC or the modified transfixed technique yielded an improved fracture strength and the fracture pattern of ETPs being restored with a universal injectable composite. [ABSTRACT FROM AUTHOR]

The mandibular first premolar is commonly a single-rooted tooth with occasional presentation of radicular variations. This tooth usually has one root with only one canal (97.9 %). Presence of three canals is very rare. Anomalies may appear during odontogenesis which can lead to anatomical variations in teeth. Similarly, these variations may be associated with characteristics that can be attributed to specific population groups. Due to their low frequency, these additional canals can easily be missed. For this reason, a meticulous knowledge of tooth morphology and their possible anatomical variations are necessary, and the presence of extra roots and canals should be always considered before initiation of root canal treatment. Additionally, different radiographs and appropriated access cavity preparation is needed to ensure a success endodontic treatment. This article reports a diagnosis and endodontic treatment of a mandibular first premolar with three canals. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Due to the complexities and variations of the root canal system's anatomy, mandibular premolars are among the most difficult teeth for endodontic treatment. The lack of clinician knowledge ultimately leads to treatment failure. Mandibular premolars are the most complicated teeth for endodontic treatment because of the variations in root canal anatomy. On the other hand, missing root canals can subsequently lead to failure of endodontic treatment, which causes the patient to become symptomatic. Therefore, the clinician's knowledge of the different types of root canal anatomy and the skill of using new equipment for proper root canal treatment improve the outcome. This study reported the successful endodontic treatment of a mandibular second premolar with four root canals by using an operative microscope. [ABSTRACT FROM AUTHOR]

Background: The purpose of the study was to investigate the behavior of hard dental structures of the teeth with abfraction lesions when experimental occlusal loads were applied. Methods: A 65-year-old patient came to the dentist because she had painful sensitivity in the temporomandibular joints and the lower right premolars. The patient was examined, and cone-beam computed tomography (CBCT) of the orofacial area was indicated. The data provided from the CBCT were processed with Mimics Innovation Suite 17 software to create the desired anatomical area in 3D format. Then, the structural calculation module was used in order to perform a finite element analysis of the lower right premolar teeth. A focused review of articles published between 2014 and 2023 from specialty literature regarding the FEA of premolars with abfraction lesions was also conducted. Results: The parcel area and the cervical third of the analyzed premolars proved to be the most vulnerable areas under the inclined direction of occlusal loads. The inclined application of experimental loads induced 3–4 times higher maximum shears, stresses, and deformations than the axial application of the same forces. Conclusions: FEA can be used to identify structural deficiencies in teeth with abfractions, a fact that is particularly important during dental treatments to correct occlusal imbalances. [ABSTRACT FROM AUTHOR]

Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human biology and evolution and is thus of interest in the fields of dental anthropology, as well as human anatomy and medicine. Of concern is also the variation of the inner aspects of the crown which can be investigated using the tools and methods of virtual anthropology. In this study, we explored inter- and intra-population morphometric variation of modern humans' upper third and fourth premolars (P3s and P4s, respectively) considering both the inner and outer aspects of the crown, and discrete traits. We worked by means of geometric morphometrics on 3D image data from a geographically balanced sample of human populations from five continents, to analyse the shape of the dentinal crown, and the crown outline in 78 P3s and 76 P4s from 85 individuals. For the study of dental traits, we referred to the Arizona State University Dental Anthropology System integrated with more recent classification systems. The 3D shape variation of upper premolar crowns varied between short and mesio-distally broad, and tall and mesio-distally narrow. The observed shape variation was independent from the geographical origin of the populations, and resulted in extensive overlap. We noted a high pairwise correlation (r1 = 0.83) between upper P3s and P4s. We did not find any significant geographic differences in the analysed non-metric traits. Our outcomes thus suggest that geographical provenance does not play a determinant role in the shaping of the dental crown, whose genesis is under strict genetic control. [ABSTRACT FROM AUTHOR]

Objective. This research study investigated the effect of new decontamination protocols on the bonding capacity of saliva-contaminated monolithic zirconia (MZ) ceramics cemented with two different monomer-containing self-adhesive resin cements. Materials and Methods. Standardized tooth preparations (4 mm. axial height) were performed for eighty human maxillary premolars under constant water cooling system. Eighty monolithic zirconia crowns (Whitepeaks Supreme Monolith) (n = 8 / 10 groups) were manufactured by CAD-CAM. Specimens were kept in the artificial saliva at pH = 7.3 for 1 minute at 37°C except control groups. The specimens have not been prealumina blasted and grouped according to cleaning methods and resin cements: control groups (C) (no saliva contamination + GPDM + 4 ‐ META (N) (CN) and 10-MDP (M) containing resin cement (CM), alumina blasted AL + GPDM + 4 ‐ META (ALN) and 10-MDP containing resin cement (ALM), zirconium oxide containing universal cleaning agent (IC) applied + GPDM + 4 ‐ META (N) (ICN) and 10-MDP containing resin cement (ICM), pumice (P) applied + GPDM + 4 ‐ META (PN) and 10-MDP containing resin cement (PM), and air-water spray (AW) applied + GPDM + 4 ‐ META (AWN) and 10-MDP containing resin cement (AWM)). Monobond Plus was applied to all surfaces for 40 seconds before cementation. The thermal cycle was applied at 5,000 cycles after cementation. The crowns were tested in tensile mode at a speed of 1 mm/min. The mode of failure was recorded. SEM examinations were carried out at different magnifications. Data were analyzed using rank-based Kruskal-Wallis and Mann–Whitney tests. Results. No significant differences were found between the surface treatments and between the two types of resin cements. Interaction effects between surface treatments and resin cements were found to be significant by two-way ANOVA analysis. ICM group resulted in significantly better bond strength results compared with CN. ICM was found to result in better bond strength results compared with PM. The combination of universal cleaning agent and 10-MDP containing resin cement had significantly the highest cementation bond strength values. The increasing order of mean tensile bond strength values of decontamination protocols was C < AW < P < AL < IC. The mean tensile bond strength of 10-MDP containing resin cement was slightly higher than GPDM + 4 ‐ META containing resin cement. Conclusions. Universal cleaning agents can be preferred as an efficient cleaning method with 10-MDP-containing cement after saliva contamination for better adhesive bond strength of 4 mm crown preparation height of monolithic zirconia ceramics. [ABSTRACT FROM AUTHOR]

Purpose: Caries or iatrogenic thermal trauma of the teeth have a significant impact on the dental pulp structure connected with stimulation of angiogenesis and lymphangiogenesis. Therefore, the aim of the study was to identify the difference in the rate of heat dissipation by vessels present in the dental pulp. Methods: Freshly extracted healthy (n = 10) and carious (n = 14) molars and premolars were cut on a diamond saw and subjected to active thermographic examination and then subjected to lymphoscintigraphy and X-ray examination. The tooth samples were heated uniformly to 40 ± 0.5 °C. A thermal imaging camera with a resolution of 640 × 320 pixels was used to record the sequence of thermograms during free cooling. Due to the different volume of teeth and different surface conditions of the examined teeth (color, roughness) and the related different radiation emissivity, the changes in the temperature (ΔT) of the tooth cross-section surface were analyzed using the subtractive method within 120 seconds from the switching off of the thermal impulse (heating). Results: Thermographic examination of healthy and cariously changed teeth revealed areas of increased tissue fluid flow combined with heat release, which may indirectly indicate the existence of vessels in these areas. On a thermal imaging camera, variations in the rate of heating or cooling across several cross-sectional sections of the same tooth indicate changes in the dental structure's density. Conclusions: In caries-affected teeth, intracanalicular fluid flows are different than those of healthy teeth. Therefore, it can be concluded that the pulp vessels enabling circulation of body fluids - blood and lymphatic - increases with the intensity of inflammation. Maintaining the homeostasis of the dental pulp depends heavily on the circulation of bodily fluids within the dental organ. [ABSTRACT FROM AUTHOR]

Recently, a dinosaur assemblage with three-dimensional preservation of the Early Cretaceous Jehol Biota has been discovered in the Ningcheng Basin, Inner Mongolia, China. Of the vertebrate fossils, a new spalacotherioid "symmetrodont" mammal is described here as Ningchengodon foxi gen. et sp. nov. The specimen is an incomplete right dentary characterized by a lower dental formula of i3/c1/p3/m5, with molar cusps in acute-triangulation. Cusps e and f embraced cusp d of the preceding molar forming a molar interlocking, reported here for the first time for acute-angled spalacotherioids. Phylogenetically, the new taxon is placed in the clade of Spalacotherioidea, and clustered at the base of the paraphyletic zhangheotheriids although its relationship is not further resolved with other zhangheotheriids. Additionally, the ultimate premolar replacement is simultaneous with the m5 eruption as in Origolestes lii and Zhangheotherium quinquecuspidens. This discovery enriches the biodiversity of spalacotherioids, and further highlights the complexity of the Zhangheotheriidae in evolution. [ABSTRACT FROM AUTHOR]

Objective: To comparatively assess the wear resistance of conventional and flowable composites containing different filler types using thermomechanical chewing simulation. Materials and Method s : Six different composite resin materials were used: a conventional and flowable composite from each of three manufacturers respectively classified by different filler characterizations: (1), a nanohybrid conventional (G‐aenial Posterior, GC) and flowable (G‐aenial Universal Injectable, GC), (2) a nanofilled conventional (Filtek One Bulk‐fill Restorative, 3M) and flowable (Filtek Ultimate Flow, 3M), and submicron‐filled conventional (Estelite Posterior Quick, Tokuyama) and flowable (Estelite Bulk‐Fill Flow, Tokuyama). The buccal surfaces of extracted human premolars were planarly abraded and used as control (n = 12). The prepared surfaces were subjected to wear using a thermocycler chewing simulator against 6‐mm diameter steatite balls for 240,000 cycles, simulating 1 year of in vivo use. Digital profiles of treated sample surfaces were scanned using a laser scanner, and the volume loss and maximum depth of loss were calculated. Two‐way MANOVA was used to compare the wear volume loss and depth according viscosity (conventional/flowable) and filler type (nanohybrid, nanofilled, submicron‐filled), and multiple comparisons were performed using Duncan's test. Results: Wear volume loss and loss depth were significantly lower in enamel than in all composite resin groups. The wear volume loss and loss depth of nanofilled composites were significantly higher than the other composite filler types, with no significant difference in either parameter between the nanohybrid and submicron‐filled composite groups. With respect to apparent viscosity, wear volume loss and loss depth of conventional composites were significantly lower than the flowable composites. Conclusions: The type of composite filler and its apparent viscosity significantly influence the in vitro wear resistance of the material. All composite materials tested demonstrated a susceptibility to simulated wear that was two to three times greater than that of human enamel. Clinical Significance: Flowable composite resins provide a level of convenience in clinical application. Despite advancements in their wear characteristics, they continue to display inferior wear resistance compared to conventional composite resins. Nevertheless, all tested composite resins exhibited a significantly higher potential for wear than human enamel. [ABSTRACT FROM AUTHOR]

(1) Background/Objectives: Accurate determination of chronological age is crucial in legal dental identification. This study aimed to compare the effectiveness of different formulas in estimating the age of a Brazilian subpopulation by analyzing the pulp/tooth ratio of the maxillary canine and mandibular second premolar in panoramic and periapical radiographs. (2) Methods: The sample consisted of panoramic and periapical radiographs of 247 individuals. The file of each radiograph was opened in the Adobe Photoshop CS4® program to outline and obtain values in pixels for calculating the pulp/tooth ratio. Statistical analysis was conducted using the SPSS program, with a significance level set at 5%. (3) Results: The interclass correlation coefficient demonstrated excellent intra-observer agreement (0.990–0.999). The determination coefficients (R2) suggested that only 30–35% of the actual age results could be explained by the pulp/tooth ratio. The smallest differences were observed with Cameriere's formula for the mandibular second premolar on panoramic radiographs (+4.1 years). The greatest differences were found with the formulas for the mandibular second premolar in panoramic radiographs of the Korean (+12.5 years) and Portuguese (−12.1 years) populations. (4) Conclusions: The equations employed showed little agreement between the actual age and the estimated age. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the root structure is important for the successful outcome of endodontic procedures. Lack of knowledge of the anatomic variations in root canal morphology can contribute to the failure of root canal therapy. One of the most anatomically diverse tooth groups is the upper first premolar. The incidence of two root canals is the most predominant anatomy observed for maxillary first premolar however some anatomical variations are also observed. The most frequent anatomical variation in these teeth is the existence of three roots with three canals. The objective of this study is to report a similar case of maxillary first premolar having three roots with separate 3 canals. Endodontic success requires a thorough understanding of root canal anatomy. The variation in the number of roots, canals, root direction, longitudinal depressions of the roots, the various shapes of the pulp cavity and the problems in visualizing the apical limit by radiographs make the endodontic procedure of these teeth quite challenging. [ABSTRACT FROM AUTHOR]

Background and Objective: Clinicians must possess a comprehensive understanding of variations in canal morphology and configuration during endodontic procedures to enhance treatment success. This study aims to assess and analyze the canal configurations of maxillary first premolars using Cone-Beam Computed Tomography within the sub-population of Western Saudi Arabia. Materials and Methods: In this cross-sectional study, following the acquisition of ethical clearance from Batterjee Medical College in Jeddah, Saudi Arabia, a retrospective examination of Cone-Beam Computed Tomography (CBCT) scans of maxillary first premolars in adult patients was conducted. The study focused on quantifying the number of canals and characterizing their configurations, with classification based on Vertucci's categorization. Results: The study examined 399 CBCT images of maxillary first premolars, revealing that type IV canal configurations were the predominant morphology (56.9%), followed by type V (24.6%). Significant gender-related disparities were observed, with females displaying a higher incidence of types I and V canals. At the same time, males exhibited a greater prevalence of types IV and VI canals. Notably, no substantial associations were discerned between canal types and age groups. Conclusion: Within the context of maxillary first premolars, type IV canal configuration emerged as the most prevalent. Gender-based distinctions were evident, with females predominantly presenting types I and V canal configurations, whereas males displayed a higher occurrence of types IV and VI canal configurations. [ABSTRACT FROM AUTHOR]

Aim: In this, in vitro study's objective is to assess the shear bond strength (SBS) of metal and ceramic orthodontic brackets that have been adhered to enamel using a conventional acid etch/primer and self-etching primer (SEP) adhesive method. Materials and Methods: One hundred excised human premolars were bonded on brackets and were divided into group 1 -Metal brackets were bonded on teeth and group 2 -Ceramic brackets were bonded on teeth. These two groups were further subdivided: subgroup 1a - 25 metal brackets bonded using conventional acid etch/primer adhesive system, subgroup 1b - 25 metal brackets bonded using SEP, subgroup 2a - 25 ceramic brackets bonded using conventional acid etch/primer adhesive system, and subgroup 2b - 25 ceramic brackets bonded using SEP; brackets were debonded using a computerized Instron universal testing machine. Results: The mean value of SBS of metal and ceramic brackets bonded using conventional acid etch/primer adhesive systems had higher SBS than those bonded using SEP. SBS ranged from 7.95 to 12.24 MPa which was in the acceptable clinical range. Conclusion: SBS values of all four subgroups exceeded the range of 6-8 MPa observed to be acceptable for routine clinical use. [ABSTRACT FROM AUTHOR]

The aims of the study were to determine the effect of different types of endodontic sealers and the presence of a horizontal glass fiber post (HGFP) on the fracture resistance and fracture pattern of mesio-occluso-distal (MOD) restored upper premolars and to analyze the stress distribution. Sixty extracted upper premolars received root canal treatment (RCT) and a MOD cavity preparation. All MOD cavities were restored with the same composite resin (CR). The 60 teeth were divided randomly into 6 groups (n = 10); Group1= AH Plus sealer; Group 2= TotalFill BC sealer; Group 3= BioRoot RCS sealer; Group 4= AH plus sealer + HGFP; Group 5= TotalFill BC sealer + HGFP; and, Group 6= Bio Root RCS sealer + HGFP. All specimens were thermocycled and subjected to cyclic loading. Next, the specimens were subjected to a static load using a universal testing machine. Data were analyzed using two-way ANOVA. Two micro-CTs of the same upper premolar, one without the HGFP and later one with HGFP inserted were made and used to create two finite element (FE) models. For the fracture resistance, two-way ANOVA revealed significant differences for the effect of HGFP (p = 0.029), but no differences for the effect of root canal sealer type (p = 0.561). The HGFP groups showed higher restorable fracture compared to groups without HGFP (p = 0.013). Finite element analysis showed that the inclusion of HGFP reduces stress concentration at the occlusal interface and cervical region. Therefore, it can be concluded that HGFP significantly increased the fracture resistance of endodontically treated upper premolars with MOD cavities and reduced the risk for non-restorable fractures. The FE analysis supports the mechanical test results. [ABSTRACT FROM AUTHOR]

Background: To determine the amount of apical extrusion between various file systems during the retreatment procedure and to determine the effect of taper on the same. Materials and Method: Seventy mandibular extracted premolars were taken, and preparation was performed using a Woodpecker file (Woodpecker Medical Instrument Co., Ltd., Guilin, China) (25/0.06). The gutta‑percha (GP) was removed from each specimen with H file (#40/0.02) to simulate retreatment in seven groups (n = 10) using ProTaper Next (PTN;Dentsply, Maillefer, Ballaigues, Switzerland) (PTN) (30/0.07), Reciproc (25/0.08), Hyflex CM (30/0.06), Mtwo (30/0.05), Neoendo flex (30/0.04), Neoendo hybrid (30/0.04), and Flexicon file (30/0.06). The specimens were held with the help of a rubber stopper and put in the Eppendorf tube of volume 4 mL (pre‑weighed before retreatment). The debris that was on the root surface of the specimen was washed with distilled water with 1 mL volume, kept in the oven, and then again weighed after 7 days. Results: Apical extrusion was found in the following order: HYFLEX CM (LEAST) < FLEXICON < PROTAPER NEXT < RECIPROC < NEOENDO FLEX < NEOENDO HYBRID < MTWO (HIGHEST). Conclusion: W Hyflex CM and Flexicon files showed lesser extrusion of debris than others. [ABSTRACT FROM AUTHOR]