Mandibular Incisors Research Articles

Multibraided Fixed Retainers with Different Diameters after Magnetic Resonance Imaging (MRI): In Vitro Study Investigating Temperature Changes and Bonding Efficacy.

Orthodontists are often asked to remove fixed retainers before patients undergo magnetic resonance imaging (MRI). The present in vitro study was designed to analyze the heating and bonding efficacy of stainless steel multibraided fixed retainers after 1.5- and 3-tesla (T) MRI. A total of 180 human mandibular incisors were used to create 45 specimens of four teeth each, divided into nine groups. Handmade multibraided fixed retainers of three different sizes, defined by the diameter of the initial wire used (0.008″, 0.010″ and 0.012″), were tested. Three groups underwent MRI at 1.5 T, another three groups underwent MRI at 3 T and the last three groups did not undergo MRI. Temperature was assessed before and after MRI. Shear bond strength (SBS) and adhesive remnant index (ARI) were assessed after MRI for all groups. Data were statistically analyzed (p < 0.05). After 1.5 T exposure, no significant temperature increase from T0 to T1 was observed in any of the groups (p > 0.05). Regarding the 3 T groups, a significant difference from T0 to T1 was found for all the groups (p < 0.05). Temperature changes were not clinically relevant, as they were less than 1 °C for all groups except for group 3 (ΔT0-T1: 1.18 ± 0.3 °C) and group 6 (ΔT0-T1: 1.12 ± 0.37 °C). Furthermore, there were no significant differences between the temperature variations associated with different wire diameters (p > 0.05). No significant changes in SBS or ARI were found (p > 0.05). Since overheating was irrelevant and adhesion values did not change, the tested devices were concluded to be safe for MRI examinations at 1.5 T and 3 T.

How accurate is predicted root movement achieved in four first-premolar extraction cases with Invisalign?

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

Temporomandibular joint disc responses to installation and removal of the experimental malocclusion.

Aberrant occlusion and aging are two main risks for temporomandibular joint (TMJ) degeneration. To assess the combined impact of occlusion and age on TMJ disc. To avoid the confounding impact of gender, presently, 126 female C57BL/6J mice, 63 youngsters, 6-week old and 63 adults, 28-week old, were used. An experimental bilateral anterior crossbite (BAC) relation was created by installing metal tubes onto the mandibular incisors. Mice were sacrificed at 3, 7 and 11 weeks (n = 9). Additionally, the installed tubes were removed at 7 weeks in removal groups and the TMJs were sampled after another 4 weeks (n = 9). Disc changes were detected by histomorphology, immunohistochemistry, and western blot assays. Disc deformation was obvious in BAC groups. The typical change was hyperplasia at the posterior region of the disc where there was significant infiltration of inflammatory cells. Expressions of the inflammatory markers, including tumour necrosis factor-α and interleukin-1β, and the catabolic markers, including fibronectin (FN), FN N-terminal fragments, and vascular endothelial growth factor-A, were all increased. The changes were more obvious in adults than in youngsters. Removal of BAC attenuated inflammatory and catabolic changes in the youngsters, but the inflammatory markers recovered little in the adults. TMJ disc responds to BAC by degeneration and inflammation, and respond to BAC removal by rehabilitation. Adult discs show severer degeneration responses to BAC and a lower level of anti-inflammatory capability to BAC removal than the youngster's discs. Animals cannot be equated with humans. The human disc response to occlusion changes worth further exploration.

Effect of Fixed and Removable Functional Therapy on Mandibular Anterior Bone Structures: A Fractal Analysis Study.

(1) Background and aim: The effects of functional therapies on dentoalveolar and skeletal structures have been investigated in orthodontics for many years. The aim of this retrospective study was to evaluate the changes caused by fixed and removable functional therapy in the mandibular anterior trabecular structures using fractal dimension (FD) analysis. (2) Methods: A total of 60 patients with skeletal and dental class II malocclusion were included in the study and three groups were formed: the untreated control group (CG), the Forsus fatigue-resistant device group (FFRDG), and the Monoblock group (MBG). Bone areas of interest determined in the buccoapical of the mandibular incisors and the symphysis in the lateral cephalometric radiographs taken before (T0) and after (T1) functional therapy were evaluated using FD analysis. The relationship between the FD and IMPA (Incisor Mandibular Plane Angle) angles was evaluated. Parametric and nonparametric tests were used in statistical analysis according to normality distribution. The statistical significance level was determined as p < 0.05. (3) Results: There was no statistically significant difference between the FD values of all groups at T0 (p > 0.05). At T1, buccoapical FD values were significantly lower in FFRDG and MBG compared to the control group (p < 0.05), while symphyseal FD values were not found to be significant (p > 0.05). The IMPA angle was significantly lower in the FFRDG and MBG than in the control group at T0, while it was higher at T1 (p < 0.05). While a significant negative correlation was observed between the IMPA angle and buccoapical FD values in both FFRDG and MBG (p < 0.05), it was not observed with the symphysis FD values (p > 0.05). (4) Conclusions: Trabecular changes caused by functional therapy in the mandibular anterior bone can be evaluated on lateral cephalometric radiographs with FD analysis. It was concluded that orthodontists should ensure controlled changes in the IMPA angle during functional therapy, especially for the decreases in FDs seen in the buccoapical alveolar region due to the forward movement of the mandibular incisors.

The effect of curcumin 1% methanolic extract on the expression of Matrix Metalloproteinase-1, Matrix Metalloproteinase-8, Matrix Metalloproteinase-13, neutrophil, macrophage, lymphocyte counts in Porphyromonas gingivalis induced periodontitis: a randomized controlled trial

ObjectiveHailed as one of the most fundamental and important treatment in management of periodontal disease, scalling and root planning has limitations regarding microorganism elimination. Meanwhile, turmeric has been proven to have a therapeutic effect on gingivitis and periodontitis. This study aimed to analyze the impact of curcumin 1% methanolic extract on the expression of Matrix Metalloproteinase-1, Matrix Metalloproteinase-8, Matrix Metalloproteinase -13, neutrophil, macrophage, and lymphocyte number in the gingiva of Wistar rats exposed to Porphyromonas gingivalis bacteria (P. gingivalis). Materials and methodsThe experimental animals used were Wistar rats, arbitrarilly split up into three experimental groups namely: normal, control (induced with periodontitis, received no treatment), and treatment (Periodontitis with 1% curcumin treatment). The samples were taken from the gingival tissue of the mandibular incisors on 1 and 7 days. Immunohistochemical and Hematoxylin Eosin staining were performed to measure the expression of Matrix Metalloproteinase-1, Matrix Metalloproteinase-8, Matrix Metalloproteinase-13, and the number of neutrophils, macrophages, and lymphocytes. Data were analyzed for mean standard deviation. The Oneway ANOVA was then performed to see whether there is a significant difference between experimental groups, the test then commenced with Tukey’s Honestly Significant Difference test with a significance level (α=0.05). ResultsMMP-8, MMP-13, neutrophil, and lymphocyte numbers in the treatment groups were significantly lower with P<0.05 than in the control groups in the 1 and 7 days. Meanwhile, in MMP-1 and macrophage numbers the difference was deemed not significant when control and treatment groups are compared. ConclusionThe administration of 1% curcumin can significantly reduce the expression of MMP-8, MMP-13, neutrophil and lymphocyte cell numbers, but there is no reducing the number of macrophage cells and MMP-1 expression in gingiva of Wistar rats exposed to P. gingivalis bacteria.

Root canal morphology of permanent mandibular anterior teeth in a Pakistani population: A cone beam computed tomography assessment.

To investigate the incidence of accessory canals and the variation in root canal morphology of permanent mandibular incisors and canines in Pakistani population using Cone Beam Computed Tomography (CBCT). A cross-sectional study was conducted in University College of Dentistry, The University of Lahore, Pakistan after getting institutional ethical permission from January 2020 to September 2022. The data included records of 111 patients consisting of 444 permanent mandibular incisors and 222 permanent mandibular canines. Accessory root, root canals and Vertucci canal configuration for each tooth was recorded. Data analysis was done using SPSS v20. Descriptive statistics were calculated for each anatomical parameter. Chi-square test was applied to determine association of gender with the presence of accessory roots and root canals. Among the 111 records evaluated, 48.6% were males and 51.4% were females. No accessory root was found in the central and lateral incisors. However, an accessory root was found in 4.9% of the canines. The incidence of accessory canals in the central incisors, lateral incisors and canines was 18.9%, 25.2% and 10.4% respectively. The most common canal configuration in teeth with accessory canals was Type-III, followed by Type-II and Type-V. None of the central or lateral incisor showed accessory root while it was detected in 4.9% canines. The frequency of accessory root canal was found to be 18.9%, 25.2% and 10.4% in central incisors, lateral incisors and canines respectively. The most common canal configuration was Type-I, followed by Type-III and Type-II. Type-V, VI and VII were less common.

Does Invisalign Outperform Fixed Appliance in Treating Vertical Discrepancies?

Aligners became popular among adult patients for their superior aesthetics and comfort in comparison to conventional fixedappliances. It has undergone numerous enhancements over time, allowing it to address more complex malocclusions. Many researchers argued that managing vertical discrepancies is more challenging than addressing anteroposterior issues. This complexity arose from the mechanical requirements for treatment and the required mechanics to prevent relapse. Studies assessing the treatment outcome of anterior open bite closure using clear aligners have yielded conflicting results regarding the mechanisms of bite closure. Proposed mechanisms included extrusion of upper or lower incisors, lingual tipping of upper or lower incisors, intrusion of upper or lower molars, counterclockwise rotation of the mandible, or various combinations of these mechanisms. The research highlighted the biomechanical challenges associated with using aligners for the treatment of deep bites as mandibular incisor intrusion and leveling the curve of Spee remain among the least predictable movements. Given the widespread use of aligners, it is imperative to rigorously assess the effectiveness of clear aligners in achieving overbite correction to ensure they deliver the desired outcome. This review aimed to assess the performance of Invisalign in the management of vertical discrepancies. It sought to identify the dentoskeletal effects of clear aligners in addressing deep bite and anterior open bite cases, understand the mechanisms behind overbite correction, and provide a comprehensive overview of the existing research on this topic.

Esthetically driven immediate provisionalization in the anterior zone: 5-year results from a prospective study evaluating 3.0-mm-diameter tapered implants

ObjectivesEvaluate the 5-year safety and efficacy of a narrow-diameter (3.0 mm) implant that was immediately provisionalized with a single crown in the maxillary lateral incisor or mandibular central or lateral incisor area.Materials and methodsAn open, prospective, single-cohort, multicenter study was conducted, in which narrow-diameter implants were placed in fresh, healed extraction, or congenitally missing sites. All patients were required to meet strict criteria for immediate loading. The primary endpoints were marginal bone levels (MBL) and MBL changes (MBLC) from implant placement to 5-year follow-up. Secondary endpoints included cumulative 5-year survival and success rates, soft tissue health, and esthetic parameters.ResultsA total of 91 implants were placed in 77 patients. The mean MBL remained stable from the 1-year (− 0.79 ± 0.73 mm, n = 75) to 5-year (− 0.74 ± 0.87 mm, n = 65) follow-up. A marginal bone gain of 0.11 ± 0.83 mm was observed from the 1-year to 5-year follow-up. The cumulative 5-year survival rate was 96.5%, and the cumulative 5-year success rate was 93%. The clinical parameters, including the modified plaque index, modified sulcus bleeding index, Jemt’s papilla index, and pink esthetic score improved throughout the 5-year study.ConclusionsThe study demonstrated that narrow-diameter implants represent a safe and predictable treatment option for subjects suitable for immediate loading and with limited bone volume or limited inter-dental space.Clinical relevanceNarrow-diameter implants with immediate provisionalization can be considered for use to restore missing or damaged teeth with predictable functional and esthetic outcomes. This trial was registered with ClinicalTrials.gov (NCT02184845).

Neonatal Riga-Fede disease: A systematic review of 84 cases collected over 120 years

Background: Traumatic ulceration of the tongue due to congenital teeth is known as Riga-Fede disease (RFD). The literature on RFD consists largely of anecdotal case reports, thereby lacking valid clinical recommendations. While managing a newborn with RFD complicated by Ludwig’s angina, this knowledge gap was recognized. Therefore, this systematic review was conducted to gain insight into the optimal management and the possible complications of RFD. Methods: A literature search was conducted using PubMed, Google Scholar, and Science Direct, supplemented with African Journals Online, Indmed, and manual searches. Papers published between 1900 and July 2023 in any language were retrieved. Neonates with natal or neonatal teeth and ulceration of the oral mucosa were included. Papers with incomplete data and review articles were excluded. Results: A total of 84 newborns with RFD from 62 published reports (including the case reported herein) were analyzed. Most of the reports were from the Indian subcontinent, and the frequency of reporting has increased since the year 2000. Tongue ulceration in all cases was due to mandibular incisors. There was no significant difference in the median duration of healing between the tooth extraction group (14 days) and the conservative management group (18 days). There was only a very weak positive correlation between the duration of symptoms and healing time, which was statistically insignificant. Conclusion: Healing of mucosal ulcers in RFD is often protracted and does not appear to be influenced by the duration of symptoms or by the modality of treatment. Extraction of the offending teeth is more common (75% of cases) than conservative management, such as grinding (ameloplasty) or resin capping of teeth. RFD is mostly a benign disorder; however, serious complications such as meningitis, Ludwig’s angina, and soft tissue abscesses can rarely occur with Staphylococcus aureus infections.

Effect of the filling technique on the filling removal from oval-shaped canals.

This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

Patterns of tooth agenesis in individuals with Down syndrome: A secondary analysis using the Tooth Agenesis Code.

Tooth agenesis (TA) is common in Down syndrome (DS). It is unknown whether this agenesis occurs in specific patterns, which is important regarding treatment planning and aetiological research. This study aimed to aggregate and analyze patterns of TA, excluding third molars, in individuals with DS using the tooth agenesis code (TAC). The study was designed as a secondary analysis, following STROSA guidelines. The search (MEDLINE-PubMed) and selection process resulted in six included studies encompassing 241 individuals with DS. TA data were systematically converted into TACs and analyzed per dentition, per jaw, and per tooth type. Symmetry was evaluated. The prediction was calculated for oligodontia. In the 155 cases with TA 86 distinct Overall-TAC patterns were identified. The most common patterns were bilateral maxillary lateral incisor agenesis (TAC002.002.000.000;10.3%), bilateral mandibular second premolar agenesis (TAC000.000.016.016;5.8%), and unilateral left maxillary lateral incisor agenesis (TAC000.002.000.000;5.2%). Symmetry in TA patterns was observed in 49.6% of TA cases in the maxilla and 52.3% in the mandible. The simultaneous absence of both mandibular central incisors had a large predictive value for oligodontia (OR12.44;95% CI:4.97-31.84; p<.001). Predominant TA patterns exist in DS. Observation of mandibular central incisor agenesis can promote early diagnosis of oligodontia in DS.

Exploring access cavity through non-carious cervical lesions: Impacts on instrumentation, obturation, and fracture resistance in mandibular incisors.

To compare the effects of Cervical Access Cavity (CervAC) and Traditional Access Cavity (TradAC) on root canal preparation, root canal filling, and fracture resistance in mandibular incisors. Twenty recently extracted and intact mandibular incisors were initially scanned using a micro-CT device. The specimens were anatomically matched to create two groups (n = 10). A wedge-shaped non-carious cervical lesion (NCCL) was created on the buccal aspect of all teeth using a double-faced segmented diamond disc. In group 1, a TradAC was prepared, whilst in group 2, access was created through the simulated NCCL using a round diamond bur 1012. After root canal preparation with Rotate instruments sizes 15/0.04, 20/0.04, and 25/0.04, the teeth were scanned again and evaluated for root canal volume and surface area, static voxels, volume of removed dental tissue, and dentine thickness. After that, the root canals were filled using the single-cone technique, teeth were restored with composite resin, and subsequently rescanned to calculate the volume of filling materials and voids. Then, the restored teeth were subjected to fracture resistance tests using a universal testing machine. Statistical comparisons between groups were performed with the Mann-Whitney test or the Student's t-test, with a statistical significance level of 5%. Statistical comparisons indicated no significant differences between groups in terms of root canal volume, surface area, static voxels, removed root dentine, root canal filling volume, percentage of voids, or fracture resistance load (p > .05). Conversely, teeth prepared with TradAC showed a significantly higher percentage of dental tissue removed from the crown (p = .001) and a greater volume of filling material remnants in the pulp chamber (p < .001) compared to the CervAC group. A significantly lower percentage reduction in dentine thickness was observed only on the mesial aspect of root at Level 1 in TradAC group (p = .008). CervAC can be considered a viable alternative approach in the presence of NCCL in mandibular incisors.

Treatment For Type II Dens Invaginatus in a Mandibular Lateral Incisor: A Report of Rare Case

Dens invaginatus is one of the developmental abnormities of the tooth which occurs with an invagination of the enamel organ into the dental papilla during tooth development. This abnormity presents a wide spectrum of morphological variations. According to Oehlers classification, in dens invaginatus type II the invagination invades above the cemento-enamel junction, connecting to the pulp; however, there is no connection with the periodontal ligament. This abnormity presents significant challenge when root canal treatment is necessary. The most frequently affected teeth are permanent maxillary lateral incisors, followed by permanent maxillary central incisors. There are limited case reports of mandibulary central incisors; however, there is no publication of mandibular lateral incisors with dens invaginatus type II. This case report aimed to present cone-beam computed tomography aided diagnosis and treatment for type II dens invaginatus in a mandibular lateral incisor with a talon cusp and a large periapical lesion.

Tissue Dissolution Ability of Sodium Hypochlorite, EDTA, Ambroxol Hydrochloride and Triphala Evaluated and Compared when used as an Irrigant on Bovine Pulp Tissue

Aim: The aim of the study is to evaluate pulp tissue dissolution ability of Sodium hypochlorite (NaOCl), Ethylenediaminetetraacetate (EDTA), Ambroxol hydrochloride and Triphala.  Methods: Pulp tissue of BOS Taurus primigenius was extracted from 20 mandibular incisors of 4 bovine jaws .Decoronation was done at the cementum–enamel junction and roots were resected at a length of 3 mm from the apex with a diamond disc connected to a electric micromotor. Pulp tissue was then taken out of the pulp chamber of the bovine tooth with a periodontal probe and cotton pliers. Specimens were weighed using a hermetic precision electronic balance (AND Company LTD) before the test to analyze the initial weight (T0) of the samples. Extracted bovine pulp tissue specimens were weighed and randomly distributed in to 4 experimental groups of 3% sodium hypochlorite, 17% EDTA, Ambroxol hydrochloride(35mg/ml), Triphala(100mg/ml) that were taken in 4 centrifugation tubes. Contents are filtered and undissolved tissue remnants collected and reweighed.  Results: Results obtained indicate that highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.  Conclusion: Highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.

Variations in Root Canal Morphology of Mandibular Incisors in a North Indian SubPopulation: A Retrospective Cone-Beam Computed Tomography Analysis

Abstract Background: There is a high failure rate of endodontic treatment in the mandibular incisors due to insufficient knowledge of the morphology. Aim: The aim of this study was to analyze the root canal morphology in mandibular incisor teeth in the North Indian subpopulation to improve the outcome of endodontic treatment. Setting and Design: A cross-sectional study was conducted at the OPD of a tertiary care institute. Materials and Methods: A total of 200 mandibular central incisors and 200 mandibular lateral incisors were selected from available cone-beam computed tomography examinations of 100 patients aged 18–79 years. They were evaluated for root canal system configuration and symmetry between right and left elements in the same individual. Statistical Analysis: Chi-square/Fisher’s exact test was used to find the association between different study variables. Results: For mandibular central incisors, type I Vertucci classification was present in 69% of cases, type II in 3.5%, type III in 18.5%, type IV in 2%, and type V in 7% of cases. For mandibular lateral incisors, type I was present in 70.5% of cases, type II in 4% of cases, type III in 19.5%, type IV in 2%, and type V in 4% of cases. There was no evidence of types VI, VII, and VIII. Symmetry of root canal morphology between left and right teeth was observed in 90% of central incisors and 93% of lateral incisors. Conclusion: Type I Vertucci configuration was the most prevalent; however, the prevalence of other configurations is also evident. Therefore, endodontists should explore the morphology of these teeth carefully while performing root canal treatments.

Correlation between root canal anatomy of mandibular incisors and premolars in Western Uttar Pradesh population of India - A cross sectional study

ABSTRACT Aim: This study aimed to evaluate the correlation between the presence of two canals in mandibular incisors and multiple canals in mandibular premolars in the Western Uttar Pradesh population of India using cone-beam computed tomography (CBCT). Methods: CBCT scans with 0.125-mm voxel size and 50 mm × 50 mm field of view of 800 patients were evaluated for the parameters; a number of canals, root canal configurations (according to Vertucci’s classification), unilateral/bilateral occurrences, and correlation between presence of two canal configuration in mandibular incisors and multiple canals (&gt;1 canal) in mandibular premolars. The data obtained were subjected to statistical analysis using the SPSS statistical program version 22.0 using the Chi-square test. The significance level was set as 5%. Results: According to the current analysis, the prevalence of mandibular incisors with one canal was 68.1% and two canals were 31.9% whereas in mandibular premolars prevalence of one canal was 71.5%, two canals were 27.2%, and three canals were 1.3%. The incidence of Vertucci type I canal configuration (68.1% mandibular incisors and 71.5% mandibular premolars) was more prevalent than the other types. The incidence of C-shaped canals was 2.6%. The prevalence of bilateral occurrence of the same canal configuration was 16.6%. A positive correlation was found between the presence of two canals in mandibular incisors with multiple canals in mandibular premolars (20.4%). Conclusion: The root canal morphology of mandibular premolar teeth of the Western Uttar Pradesh Indian population is complex. Two canals in mandibular incisors are frequently associated with multiple canals in mandibular premolars.

Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study.

To assess and compare the mandibular intercanine width (ICW) of children at three stages of mixed dentition in children at Namakkal district. An analytical cross-sectional study was conducted among 135 schoolchildren aged 7-11 years, with 45 children in each group. Group I included children with completely erupted permanent mandibular central incisors, group II included children with completely erupted permanent mandibular central and lateral incisors, and group III included children with completely erupted permanent mandibular central incisors, lateral incisors, and canines. Impressions were made in the mandibular anterior region, and study casts were prepared. Measurements of the mandibular ICW were taken using a digital vernier caliper. The mean mandibular ICW after the complete eruption of permanent mandibular central incisors, lateral incisors, and canines was 23.7, 25.5, and 25.7 mm, respectively. There was a statistically significant difference in the ICW between the three groups (p < 0.001). Post hoc tests showed that mandibular ICW was statistically significant between groups I and II and group III (p < 0.001). Linear regression analysis showed that age does not contribute to the changes in mandibular ICW. The average mandibular ICW found can be a standard comparison for treatment planning in the western Tamil Nadu population. Mandibular ICW reaches its maximum after the eruption of permanent mandibular lateral incisors. Changes in mandibular ICW should be attributed to the eruption of permanent mandibular anterior teeth and not to the age of the child. Balaraman C, Asokan S, Pollachi Ramakrishnan GP, et al. Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(7):737-741.

Effect of the Proximity of Roots to the Cortical Plate and Inclination of Incisors on External Apical Root Resorption

Abstract Background: External apical root resorption (EARR) is an unfavorable side effect of orthodontic treatment. Orthodontic treatment of patients with increased crowding could lead to the proclination of incisors and proximity of roots to the cortical plates. Aims: The aim of this study was to evaluate the effects of the proximity of the labial and lingual cortical plates and the inclination of incisors on EARR. Settings and Design: Twenty-six patients (age: 13.39 years) with nonextraction fixed orthodontic treatment were evaluated at pretreatment and posttreatment (52 cone-beam computed tomographies). Materials and Methods: The maxillary and mandibular incisors (416 teeth) were evaluated for the pretreatment predictors such as the labial and palatal (lingual) cortical plate thickness, width of the mandibular symphysis/maxillary alveolus and cancellous bone, position of the root apex in cancellous/cortical bone, and treatment factors such as distance of root to the labial and palatal (lingual) outer and inner cortical plate and incisor inclination. Statistical Analysis Used: Statistical analyses were performed with R software at a 0.05 significance level. Each parameter was compared between pretreatment and posttreatment by a paired t-test, and the association to root resorption was performed using a regression model. Results: Clinically significant (&gt;1 mm) root resorption was observed in 35% of all mandibular incisors and 52% of all maxillary incisors. Width of cancellous bone, position of the root apex in cortical bone, proximity of the root apex to the labial and palatal (lingual) outer cortical plate, lingual inner cortical plate, and proclination of incisors were significant factors associated with EARR. Conclusions: Proximity to the cortical plates and proclination of incisors are associated with increased EARR.

Establishment of Cephalometric Hard Tissue Profile among Bengali and Caucasian Populations for Orthognathic Surgery

ABSTRACT The study aimed to compare cephalometric hard tissue profile values and analysis between Bengali and Caucasian populations. The study included 100 individuals (50 males, 50 females) aged 18–35. Subjects having class I molar occlusions and well-balanced facial profiles were included in the study. Lateral cephalograms were taken with consent, and a prestructured proforma recorded relevant information and cephalometric measurements. Our study found increased posterior cranial base length in Bengali males and increased anterior cranial base length in both sexes. Bengali males had a less convex profile, while females had a more convex profile compared to Caucasians with similar mandibular features. Increased maxillary and mandibular incisor proclination was observed. Our findings indicate the necessity for separate norms for orthognathic surgery in normal ethnic Bengali adults.

Laser-assisted Root Canal Filling Removal of Lower Incisors - A Micro-CT Study.

To compare the efficiency of root canal filling removal from oval-shaped root canals with high-energy Er:YAG laser and additional instrumentation with a rotary Ni-Ti XP-Endo Finisher R system. The in vitro study was accomplished on 12 freshly extracted single-rooted mandibular incisors with one straight oval-shaped root canal, shaped with XP-Endo Shaper 30/.04 and obturated by using the warm vertical condensation technique subjected to further endodontic orthograde retreatment. Group 1: the first retreatment was carried out using a high-energy Er:YAG laser (n = 12). Group 2: the additional retreatment of the same specimens was performed with the XP-Endo Finisher-R system (n = 12). The effectiveness of the retreatment techniques was evaluated by a threefold micro-CT examination. The amount of the remaining root canal filling material was analyzed by Mann-Whitney U test and Friedman tests. A significant decrease in the quantity of the root canal filling was found following the first and after the second retreatment, compared to the initial values in all examined sections (P < 0.001). Within groups, additional application of the Ni-Ti system resulted in no significant removal of the filling materials (P > 0.05). None of the systems resulted in complete root canal filling removal. Despite the improved results after the application of the supplementary retreatment protocol, none of the root canal walls were completely clean in the apical area. The high-energy Er:YAG laser and XP-Endo Finisher R rotary system can be successfully used in endodontic orthograde retreatment under relevant operating parameters.