Craniofacial features and incisor position design of esthetics population after orthodontic treatment.

OBJECTIVES: This study aims to provide craniofacial features and incisor position prediction models among esthetics population after orthodontic treatment. METHODS: A total of 338 patients with esthetic profiles were selected from 1 055 post-orthodontic adults based on inclusion and exclusion criteria and scored by five dental students. Mean values of cephalometric measurement were demonstrated with gender and sagittal skeletal pattern (ANB) differences assessed by generalized estimating equation. Correlations among age, skeletal, and soft tissue variables in different genders were determined. Multivariate analysis was used to assess the influence of skeletal and soft tissue variables on orthodontic incisor position. RESULTS: Within the esthetic cohort after orthodontic treatment, gender differences existed in cranial and mandibular length, mandibular rotation, protrusion of pogonion, inclination of maxillary incisors, upper lip thickness, lower 1/3 face height, and nose protrusion. However, in class Ⅰ malocclusion, the development of the chin showed no significance, whereas the protrusion of the lower lip significantly differed between genders, with less protrusion in males. In males, the protrusion of lip and chin varied among groups, with thinner basic upper lip thickness of class Ⅱ than class Ⅰ and greater lower lip height of class Ⅲ than class Ⅰ. In females, the protrusion and height of the upper lip and chin varied in groups, with thicker basic upper lip thickness of class Ⅲ than class Ⅰ. Upper lip thickness, female basic upper lip thickness, and female lower lip height were correlated with age. The protrusion of the upper lip was mainly correlated with posterior cranial base, mandibular body length, ANB in male and SNA, ANB, sagittal maxillary length, mandibular rotation, and protrusion of pogonion in female. The protrusion of the lower lip in males was mainly correlated with ramus height, mandibular rotation, protrusion of pogonion in male and ANB, mandibular rotation, and protrusion of pogonion in females. After employing skeletal variables to fit dental parameters, optimal results were achieved in male IMPA (adjusted R2=0.712) and female G Vert-U1 (adjusted R2=0.795). After employing skeletal and soft tissue variables simultaneously, optimal results were achieved in male and female G Vert-U1, which was mainly influenced by the protrusion of the chin and nasal base in males (adjusted R2=0.836) and the protrusion of the nasal base as well as ANB in females (adjusted R2=0.842). CONCLUSIONS: This study demonstrated the craniofacial features of esthetics population after orthodontic treatment and revealed the correlation of gender, age, skeleton, and soft tissues to provide reliable prediction models for aesthetic orthodontic incisor position.

Analysis of factors affecting bone volume changes after immediate implantation in the maxillary central incisor.

OBJECTIVES: This study aimed to evaluate the clinical outcomes of immediate implantation of single maxillary central incisor and explore factors affecting post-implant bone volume. METHODS: Clinical data and imaging records from pre-surgery, the day of surgery, and 6 months post-surgery of 100 patients (100 implants) with non-salvageable maxillary central incisors who underwent immediate implantation were collected. Bone thickness at the cervical, middle, and apical regions of the implant's labial and palatal sides were measured immediately post-surgery and at 6 months, and bone volume changes were observed. A regression analysis model was used to assess predictive factors for labial and palatal bone plate thickness. RESULTS: At 6 months post-surgery, the labial bone thicknesses at the cervical, middle, and apical regions were 2.35, 2.29, and 3.28 mm, respectively, and those of the palatal side were 0.00, 2.40, and 6.05 mm, respectively. The cervical region had the highest alveolar crest collapse rates, with 32.87% on the labial side and 62.20% on the palatal side. The regression model indicated that factors influencing the thickness of bone at the cervical labial side of the implant included initial bone thickness, the implant center to adjacent tooth center angle, implant diameter, and the type of implant closure (P<0.05). The initial bone thickness on the palatal side was the sole predictor for bone thickness on the palatal side (P<0.05). CONCLUSIONS: Immediate implantation of single maxillary central incisors yields effective clinical results. The thickness of new bone around the implant is influenced by multiple factors. A comprehensive consideration of these factors in the planning of immediate implantation is necessary to achieve optimal therapeutic outcomes.

Lower incisor position in skeletal Class III malocclusion patients: a comparative study of orthodontic camouflage and orthognathic surgery.

OBJECTIVES: To determine the difference between orthodontic camouflage and orthodontic-orthognathic surgery using the traditional cephalometric measurement IMPA and the newly proposed IA/PAMD, the angle between the long axis of the lower incisor (IA) and the principal axis of the mandibular alveolus (PAMD). MATERIALS AND METHODS: This study included 40 cases each in the orthodontic camouflage group (OG) and orthodontic-orthognathic surgery group (SG). The differences between the IMPA and IA/PAMD before and after treatment were compared between the two groups. T0 lateral cephalometric images of the 10 cases with the highest and lowest increase in the IA/PAMD were analyzed to identify characteristics associated with a higher risk of overdecompensation of the lower incisors during presurgical orthodontic treatment. RESULTS: Both the OG and SG showed a significant improvement in hard- and soft-tissue measurements. However, in the OG, there was significant lingual inclination of the lower incisor but only a small change in the IA/PAMD. In the surgical group, the IMPA was close to 90° after treatment, but the IA/PAMD significantly increased. CONCLUSIONS: In orthodontic camouflage, the lower anterior teeth were significantly moved lingually with a better root-bone relationship. However, this relationship deteriorated in some surgical patients. Therefore, it is important to conduct cephalometric or cone-beam computed tomography examinations during preoperative orthodontics to identify and prevent possible periodontal risks.

Evaluation of dentoalveolar changes following maxillary incisor intrusion with one vs two anterior miniscrews in subjects with gummy smile: a randomized clinical trial.

OBJECTIVES: To examine dentoalveolar changes following intrusion of maxillary incisors with one or two anterior miniscrews in subjects with gummy smile and deep bite. MATERIALS AND METHODS: Forty-three subjects were selected and divided into two groups: group I (22 subjects: 15 women, 7 men; mean age 30 ± 10 years) received one miniscrew between the upper central incisors, and group II (21 subjects: 16 women, 5 men; mean age 30 ± 10 years) received two miniscrews between the canines and lateral incisors. Dentoalveolar parameters, including amount of intrusion, root resorption, incisor inclination, alveolar bone thickness, and buccal alveolar crest height (cementoenamel junction to labial alveolar crest), were evaluated using cone-beam computed tomography scans obtained before and after intrusion. The intergroup comparison was analyzed using a paired t-test and unpaired t-test to determine significant changes within and between groups. RESULTS: The amount of intrusion was significantly greater in group II than in group I (P < .05). No statistically significant differences were found between groups I and II for changes in incisor inclination, labial bone thickness, and buccal alveolar crest height (P > .05). CONCLUSIONS: Maxillary central and lateral incisor intrusion was significantly greater in subjects treated with two miniscrews. Root resorption of the maxillary central incisors was notably greater in subjects with one miniscrew, while maxillary lateral incisor resorption was greater in subjects treated with two miniscrews.

Influence of Invisalign precision bite ramp utilization on deep bite correction and root length in adults.

OBJECTIVES: To assess the influence of Invisalign precision bite ramp use on skeletal deep overbite correction and root length and volume of maxillary anterior teeth. MATERIALS AND METHODS: This was a retrospective study of 60 adults with skeletal deep overbite. Patients were divided into three groups: Invisalign (Align Technology, San Jose, Calif) with precision bite ramps (Invisalign with Bite Ramps [IBR] = 12), Invisalign with no bite ramps (INBR = 22), and full-fixed appliances (FFA = 26). Cone beam computed tomography records at T1 (pretreatment) and T2 (posttreatment) were used to measure eight skeletal, nine dental, and three soft-tissue cephalometric variables. Maxillary anterior teeth root length (mm), root volume (mm3), and percent root volume loss between T1 and T2 (%) were also recorded. RESULTS: Significant changes from T1 to T2 among the three groups were seen in ANB(o), lower face height (%), ODI (overbite depth indicator) (o), and U1-SN (o). Reduction in root length was significantly less (P < .001) in the INBR and IBR groups compared to the FFA group. Reduction in root volume and percent volume loss were significantly higher in the INBR group compared to the IBR group (P < .001), but the difference between the two Invisalign groups and the FFA group was not significant. CONCLUSIONS: Skeletal deep overbite correction using Invisalign with or without bite ramps is comparable to FFA. Reduction in root length was significantly less with Invisalign compared to FFA. Bite ramps influenced root volume and volume loss but not root length.

Fluctuating arch symmetry: a comparison of two methods of assessment - applicability and efficiency.

INTRODUCTION: Symmetry is balance, some correspondence in the size, form, and arrangements of parts on opposite sides of a plane, line, or point. The opposite of this concept is asymmetry, or imbalance. OBJECTIVE: This retrospective study compared two methods for assessing arch symmetry with linear measurements based on triangles, to determine their applicability and efficiency. METHODS: Two groups were enrolled: children (n=20) and adults (n=20), and the arch symmetry was assessed from linear measurements. Method 1: the incisor-canine (INC), canine-molar (CM), and incisor-molar (INM) distances (paired t-test and Pearson correlation). Method 2: a mathematical equation between the cusps measurements of the canines and the distobuccal of the first molars leading to result 1 (t-test for one sample and bootstrapping analysis). Dental casts were digitized and analyzed using a software program. The Bland-Altman test compared the methods (α=0.05). RESULTS: The Bland-Altman test revealed concordance between the methods; however, separately the results were different: In method 1, the mandibular arch did not demonstrate correlation (children, INC r=0.33; CM r=0.45; INM r=0.51; adults, CM r=0.46; INM r=0.35), however, the maxilla revealed a strong correlation in children and a strong/moderate correlation in adults. In method 2, both arches were symmetrical (p>0.05). CONCLUSION: Method 1 may be appropriate during orthodontic treatment, and method 2 may be indicated for final treatment. These methods are useful; however, only method 1 identified the side of asymmetry. The methods can contribute to future studies in syndromic and non-syndromic patients, before and after orthognathic surgeries and orthodontic treatment, comparing results.

Root volume measurements of maxillary canines and lateral incisors in patients with unilateral maxillary canine impaction.

OBJECTIVE: This study aimed to assess root volumes of maxillary canines and adjacent lateral incisors in patients with unilateral maxillary canine impaction. METHODS: This cross-sectional study was performed on cone-beam computed tomography (CBCT) scans of 100 patients (49 females and 51 males) with unilateral maxillary canine impaction. The images were loaded in Planmeca Romexis Viewer, and root layers between the cementoenamel junction and apex were reconstructed at 600-µm intervals. At each layer, the root boundary was marked, and finally, the root volume was calculated by multiplying the layers' area by the thickness of 600 µm. The root size of canines and lateral incisors was compared between the impaction and normal eruption sides. RESULTS: Sixty-two patients showed buccal canine impaction, and 38 presented palatal impaction. The mean root volume of canines on the impaction side was significantly greater than that on the normal eruption side; either the tooth was buccally or palatally impacted (p<0.001). The lateral incisors on the side of buccally-impacted canines showed a significantly smaller root volume than that of the contralateral side (p<0.001). However, there was no significant difference in the root size of lateral incisors between the two sides in cases presenting palatal canine impaction (p=0.177). CONCLUSION: The difference in root volume of canines between the two sides can serve as an indicator of canine impaction. The reduction in the root size of the lateral incisor on the side of the buccally impacted canine may be due to root resorption created by pressure from the canine's crown.

Effect of glide path preparation on the apical debris extrusion for three single-file systems.

BACKGROUND: The dentinal debris produced during root canal preparation can be extruded through the apical foramen, which may cause undesired consequences, such as the postoperative inflammation of periapical tissues. OBJECTIVES: The aim of the present in vitro study was to evaluate the effect of glide path preparation on apical debris extrusion for the Reciproc®, WaveOne Gold® and One Curve file systems. MATERIAL AND METHODS: A total of 72 mandibular incisors were divided into 6 groups according to the nickel-titanium (NiTi) system used and glide path preparation: group Rp - Reciproc; group Rp-O - Reciproc after glide path preparation; group WG - WaveOne Gold; group WG-O - WaveOne Gold after glide path preparation; group OC - One Curve; and group OC-O - One Curve after glide path preparation. The preand post-instrumentation weight of Eppendorf tubes was measured. The pre-weight was subtracted from the post-weight to calculate the amount of apically extruded debris. The data was analyzed using the one-way analysis of variance (ANOVA) with the statistical program PASW Statistics for Windows, v.18.0. RESULTS: No statistically significant differences were found between the single-NiTi file systems with different kinematics in terms of apical debris extrusion, with or without glide path preparation (p > 0.05). CONCLUSIONS: The amount of apically extruded debris was not affected by the kinematics of different single-NiTi file systems. Moreover, creating a glide path had no effect on the apically extruded debris in straight root canals.

Palatal groove associated with periodontal lesions: a systematic review illustrated by a decisional tree for management.

BACKGROUND: Palatal groove represents a relatively uncommon developmental root anomaly, usually found on the palatal aspect of maxillary incisors. While its origin is controversial, its presence predisposes to severe periodontal defects. AIM: This study aimed to provide a systematic review of the literature focusing on the varied diagnostic techniques and treatment modalities for periodontal lesions arising from the presence of palatal groove. Based on the existing evidence and knowledge, the study also provides a comprehensive decisional tree, guiding clinicians in the challenging decision-making process face to a palatal groove. METHODS: The literature search was conducted on Medline and Cochrane databases by two independent reviewers, who also performed the screening and selection process, looking for English written articles reporting on diagnosis and management (all treatment approaches) of periodontal lesion(s) associated with a palatal groove. Based on this literature, a comprehensive decisional tree, including a standardized palatal groove evaluation and tailored treatment approaches, is proposed. Moreover, a clinical case is described to demonstrate the practical application of the developed decisional tree. RESULTS: Over a total of 451 articles initially identified, 34 were selected, describing 40 patients with 40 periodontal lesions associated with palatal grooves. The case report illustrates a deep, large, circumferential intra-bony defect on the palatal side of the tooth #22 associated with a shallow, moderately long palatal groove in an 18-year-old male patient. Following reevaluation, a single flap surgery was deemed necessary, combined with a regenerative procedure. At 2 years post-treatment, the tooth #22 is healthy, in a functional and esthetic position. The decision-making process, based on local and systemic patient's conditions, should allow an early and precise diagnosis to prevent further complications and undertake an adequate treatment. CONCLUSION: Palatal grooves are relatively rare; however, they are frequently associated with severe periodontal defects. The identification, diagnosis, prompt, and tailored management of the associated lesion is essential to mitigate potential periodontal and endodontic complications related to the presence of palatal groove. SYSTEMATIC REVIEW REGISTRATION: [ https://www.crd.york.ac.uk/prospero/ ], identifier [C CRD42022363194].

Fgf9 promotes incisor dental epithelial stem cell survival and enamel formation.

BACKGROUND: Understanding the role of cytokines in tooth development is critical for advancing dental tissue engineering. Fibroblast growth factor 9 (FGF9) is the only FGF consistently expressed throughout dental epithelial tissue, from the initiation of tooth bud formation to tooth maturation. However, mice lacking Fgf9 (Fgf9-/-) surprisingly show no obvious abnormalities in tooth development, suggesting potential compensation by other FGFs. Here we report findings from an Fgf9S99N mutation mouse model, a loss-of-function mutation with a dominant negative effect. Our study reveals that Fgf9 is crucial for dental epithelial stem cell (DESC) survival and enamel formation. METHODS: To dissect the role of Fgf9 in tooth development, we performed the micro-CT, histomorphological analysis and gene expression assay in mice and embryos with S99N mutation. In addition, we assessed the effect of FGF9 on the DESC survival and dental epithelial differentiation by DESC sphere formation assay and tooth explant culture. Cell/tissue culture methods, gene expression analysis, specific inhibitors, and antibody blockage analysis were employed to explore how Fgf9 regulates enamel differentiation and DESC survival through both direct and indirect mechanisms. RESULTS: The Fgf9S99N mutation in mice led to reduced ameloblasts, impaired enamel formation, and increased apoptosis in the cervical loop (CL). DESC sphere culture experiments revealed that FGF9 facilitated DESC survival via activating ERK/CREB signaling, without affecting cell proliferation. Furthermore, in vitro tissue culture experiments demonstrated that FGF9 promoted enamel formation in a manner dependent on the presence of mesenchyme. Interestingly, FGF9 stimulation inhibited enamel formation in isolated enamel epithelia and DESC spheres. Further investigation revealed that FGF9 supports DESC survival and promotes amelogenesis by stimulating the secretion of FGF3 and FGF10 in dental mesenchymal cells via the MAPK/ERK signaling pathway. CONCLUSIONS: Our study demonstrates that Fgf9 is essential for DESC survival and enamel formation. Fgf9 performs as a dual-directional regulator of the dental enamel epithelium, not only inhibiting DESC differentiation into ameloblasts to preserve the stemness of DESC, but also promoting ameloblast differentiation through epithelial-mesenchymal interactions.

Simultaneous labial and lingual augmented corticotomy assisted presurgical orthodontics in class III patients: the morphological aspects of the mandibular anterior ridge with cone-beam computed tomography.

OBJECTIVES: This study aims to investigate the changes in alveolar bone following the simultaneous performance of labial and lingual augmented corticotomy (LLAC) in patients with insufficient alveolar bone thickness on both the labial and lingual sides of the mandibular anterior teeth during presurgical orthodontic treatment. MATERIALS AND METHODS: Thirth-five surgical patients with skeletal Class III malocclusion were included: 19 (LLAC group) accepted LLAC surgery during presurgical orthodontic treatment, and 16 (non-surgery group, NS) accepted traditional presurgical orthodontic treatment. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T0) and at the completion of presurgical orthodontic treatment (T1). The amount of vertical alveolar bone and contour area of the alveolar bone in the labial and lingual sides of mandibular incisors were measured. RESULTS: After presurgical orthodontic treatment, the contour area of the alveolar bone at each level on the lingual side and alveolar bone level on both sides decreased significantly in the NS group (P < 0.001). However, the labial and lingual bone contour area at each level and bone level increased significantly in the LLAC group (P < 0.001). The bone formation rate in the lingual apical region was the highest, significantly different from other sites (P < 0.001). CONCLUSIONS: During presurgical orthodontic treatment, LLAC can significantly increase the contour area of the labio-lingual alveolar bone in the mandibular anterior teeth to facilitate safe and effective orthodontic decompensation in skeletal Class III patients. CLINICAL RELEVANCE: This surgery has positive clinical significance in patients lacking bone thickness (< 0.5 mm) in the labial and lingual sides of the lower incisors.

Comparative evaluation of antimicrobial efficacy of various intracanal medicament in young permanent teeth: An in vivo study.

INTRODUCTION: Bacteria and their byproducts are key contributors to the onset and perpetuation of pulpoperiapical pathosis. Intracanal medication is vital in achieving successful endodontic outcomes as it targets and eradicates remaining microorganisms following biomechanical preparation. AIM AND OBJECTIVE: The aim of the study was to compare and evaluate the antimicrobial efficacy of calcium hydroxide (CH) paste, triple antibiotic paste (TAP), and probiotics (PBs) as intracanal medicament in 12-17-year-old children undergoing root canal treatment for the management of infected pulpal tissues in young permanent teeth. MATERIALS AND METHODS: A total of 30 patients aged 12-17 years indicated for endodontic therapy in maxillary incisors and with no systemic complications were selected. They were randomly divided into three groups, i.e., Group I - CH group, Group II - TAP, and Group III - PB allocating 10 teeth in each group. After access opening, the first sample (S1) was collected by inserting a paper point into the root canal, the second sample (S2) was collected immediately after biomechanical preparation, and the third sample (S3) was collected after 7 days, i.e., postintracanal medication. Samples were sent for microbiological analysis to assess the microbial count, and statistical analysis was done for the obtained data. RESULTS: The three intracanal medicaments were successful in reducing the microbial counts of Enterococcus faecalis in the infected root canals. However, according to the results of the study, the PB group demonstrated greater effectiveness against E. faecalis compared to the CH group and displayed similar antimicrobial efficacy as the TAP group. CONCLUSION: PB exhibited antimicrobial efficacy comparable to TAP but greater than Ca (OH) 2 paste. Hence, PB can be utilized as an intracanal medicament in young permanent teeth.

Effect of temperature on rehydration and fracture resistance of reattached tooth fragments after crown fracture: An in vitro study.

BACKGROUND: Uncomplicated crown fractures of maxillary anterior teeth are common dental injuries, and the bonding of fractured fragments is recommended for management. Rehydration of fragments improves bonding and fracture resistance. Therefore, the aim of this study was to compare the fracture resistance of the reattached tooth fragment of the incisor crown after rehydration using either a steamer or a humidifier. MATERIALS AND METHODS: Bovine teeth were used as a model. Fractured fragments were divided into three groups: Group I (no rehydration), Group II (rehydration by humidifier), and Group III (rehydration by steamer). Fragments were reattached using a standard bonding protocol. Fracture resistance was tested using a universal testing machine. Statistical analysis was performed using analysis of variance and Chi-square tests. RESULTS: The force required to fracture the reattached fragments was significantly higher in Group II (humidifier) compared to Group I (no rehydration) (P = 0.005). Group III (steamer) had a force value similar to Group I, indicating no significant improvement in fracture resistance with steamer rehydration. The temperature inside the steam-based chamber reached an average of 95.7°C with 95% humidity, whereas the conventional humidification chamber had an average temperature of 39.2°C and 84% humidity. CONCLUSION: Within the limitations of the present study, the rehydration protocol using a steam-based chamber was found to have a significantly lower force required to fracture the reattached fragments as compared to humidifier-based chamber. This was not significantly different from the fragments which were reattached without rehydration.

Treatment of absent maxillary lateral incisors: orthodontic space closure and associated procedures.

Missing maxillary lateral incisors can be treated either with orthodontic space closure or preservation of the edentulous space for tooth replacement. Orthodontic space closure coupled with non-invasive post-orthodontic cosmetic dentistry is a compelling option compatible with optimal function, favourable aesthetics, and periodontal health in the long-term. We present the rationale for space closure and detail contemporary clinical strategies underpinning interdisciplinary treatment planning and excellence in finishing.

Root canal configuration of human permanent anterior teeth: A cross-sectional study using cone-beam computed tomography in the Pakistani population.

Objectives: To analyse and document internal root morphological variations in permanent anterior teeth using conebeam computed tomography. METHODS: The cross-sectional, retrospective study was conducted from January 21 to June 19, 2021, at Jinnah Magnetic Resonance Imaging and Body Scan, and comprised data from July to December 2020 related to all the patients who had been referred to the centre for dental cone-beam computed tomography scan. The scans were evaluated at the Radiology Department of the School of Dentistry at Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan. The morphology of the roots and root canals in all permanent anterior teeth was examined. Root canal configuration was categorised using Vertucci's classification. Data was analysed using SPSS 20. RESULTS: Of the 211 patients, 116(55%) were females and 95(45%) were males. The overall mean age was 39.9±1.02 years (range: 15-65 years). All the permanent anterior teeth exhibited a single root, with the exception 2(0.9%) mandibular right and 4(1.9%) left canines which had double roots. Type I root canals were observed in all 211 (100%) maxillary right central incisors, maxillary left central incisors and maxillary left canines. Among maxillary right canines, 208(98.6%) had type-I root canals, and the corresponding value for maxillary right lateral incisors was 209(99.1%), and for maxillary left lateral incisors, the value was 210(99.5%). Root canal polymorphism had no significant association with gender (p>0.05). CONCLUSIONS: The presence of type-I root canal was common in permanent anterior teeth, and there was significant association of root canal polymorphism with gender.

Evaluation of apically extruded debris during root canal filling material removal in teeth with external apical root resorption: a comparison of different obturation techniques.

BACKGROUND: Root canal retreatment is necessary when initial treatment fails. Nickel-titanium systems help remove filling materials; however, some methods can cause canal content extrusion, resulting in inflammation and delayed healing. This study aimed to examine the impact of different preparation techniques and endodontic file systems on apical debris volume to limit material dispersion to periradicular tissues. METHODS: Ninety extracted maxillary incisors were evaluated. Simulated apical root resorption was created by removing the apical 2 mm of the root. The teeth were divided into two groups: one filled with a single cone and the other with cold lateral compaction (CLC). Each group was further divided into three subgroups (n = 15 each): Subgroup 1 used Reciproc R25 for removal and R50 for final preparation; Subgroup 2 used ProTaper Universal Retreatment (PTUR) files D1, D2, and D3 for removal and ProTaper Next X5 for finalization; and Subgroup 3 used VDW.Rotate Retreatment (VDW.RotateR) for removal and VDW.Rotate 50.04 for completion. Debris from retreatment was collected in pre-weighed tubes to determine the amount. The apical extrusion data underwent a two-way analysis of variance. RESULTS: The Reciproc group had a mean extruded debris weight of 0.54 ± 0.24 mg, higher than the PTUR (0.28 ± 0.15 mg) and VDW.RotateR (0.39 ± 0.29 mg) groups (p < 0.05). The single-cone technique (SCT) resulted in a mean debris weight of 0.34 ± 0.23 mg, lower than the CLC technique, which had a mean of 0.46 ± 0.27 mg (p < 0.05). SCT had a shorter retreatment duration (111.12 ± 33.46 s) compared to CLC (176.26 ± 52.26 s) (p < 0.05). CONCLUSION: The Reciproc file system and the CLC obturation technique resulted in greater apical debris extrusion than the other methods. SCT was quicker than CLC. The Reciproc groups are more susceptible to apex extrusion during retreatment.

Retrospective epidemiological study of the width of maxillary diastema in patients from northeastern Bulgaria.

INTRODUCTION: A maxillary diastema (MD) is identified when the gap between the central incisors exceeds 0.5 mm. It poses an a and phonetic concern, often seen in mixed dentition and occasionally continuing into permanent dentition.

Reliability of Moyer's and Tanaka Johnston's prediction methods in a non-Caucasian heterogeneous population - a cross-sectional study.

INTRODUCTION: Mixed dentition analyses are used to determine possible tooth-size and arch-length discrepancies during the transition from primary to permanent dentition. Prediction methods using a probability table or linear regression equation use the sum of the mesiodistal widths of mandibular permanent incisors to predict the mesiodistal width of unerupted permanent teeth. Racial and sexual variations and sexual dimorphism in tooth size have been reported. The objective of this study is to validate Moyer's and Tanaka Johnston's mixed dentition analyses in a contemporary South Indian population.

The dimensions of preformed nickel-titanium archwires measured at the bracket positions corresponding to the central incisor, canine, and first molar.

INTRODUCTION: Variation in the thickness of commercially available preformed rectangular archwires at the bracket positions has not been thoroughly studied. Therefore, this study measured the edgewise (height) and flatwise (width) dimensions of preformed rectangular nickel-titanium (NiTi) archwires at bracket positions corresponding to the central incisor, canine, and first molar and compared them among bracket positions. METHODS: Sixty types of preformed rectangular NiTi mandibular archwires indicated as 0.019 × 0.025-in were obtained from 14 manufacturers. The height and width dimensions of archwires were measured at 4 points (3 bracket positions corresponding to the central incisor, canine, and first molar, and 1 terminal end) of each side of each archwire using a micrometer and compared with the indicated dimensions using 1-sample t tests. Furthermore, the measured dimensions were compared among the 3 bracket positions using a 1-way analysis of variance and Bonferroni post-hoc test. RESULTS: The measured dimensions were significantly smaller than the indicated dimensions for all points except the central incisor point for height and significantly smaller than the indicated dimensions for all points for width. Comparisons among points showed that for height, the central incisor point was significantly larger than the first molar and terminal points. However, no significant differences were found for width at any point. CONCLUSIONS: The measured dimensions of preformed NiTi archwires at the bracket positions were generally smaller than the indicated dimensions, with variations observed not only among products but also among manufacturers.