Permanent Mandibular Incisors Research Articles

Assessment of Fracture Resistances of Endodontically Treated Teeth Filled with Different Root Canal Filling Systems.

Background:The motive of endodontic therapy is cleaning, shaping, and subsequently obturation. This study assessed different root canal filling systems in terms of fracture resistances of endodontically treated teeth.Methodology:This study was conducted on eighty single-rooted permanent mandibular incisor teeth which were divided into five groups: Group I was negative control; Group II was positive control; Group III comprised of gutta-percha/AH Plus; Group IV comprised of Thermafil/AH Plus; and Group V Resilon/Epiphany SE. Universal testing machine measured fracture resistance.Results:The mean fracture resistance in Group I was 458.6 ± 112.4 N, in Group II was 214.8 ± 104.6 N, in Group III was 428.6 ± 108.2 N, in Group IV was 388.2 ± 126.2 N, and in Group V was 334.8 ± 102.7 N. The difference found to be statistically significant (P < 0.05). Intergroup comparison showed a statistically significant difference (P < 0.05) between Groups I-II, I-V, II-III, and II-IV.Conclusion:The authors found that lateral condensation performed with AH Plus sealer and gutta-percha and the Thermafil technique were the highest among all other methods.

Two-phase orthodontic treatment of two different types of tooth transposition in the same patient.

Orthodontic treatment is thoroughly planned considering the patient's facial and dental characteristics, the main complaint, treatment time and the orthodontist's experience. Transposition is a form of ectopia, in which two adjacent teeth exchange positions in the dental arch. Transposition can be partial or complete. This article reports the treatment of a female patient with two kinds of tooth transposition managed in the mixed and permanent dentitions. A girl, aged eight years and three months, came to routine paediatric consultation with an ectopic permanent mandibular left lateral incisor in the mixed dentition. Radiographic analysis indicated partial transposition of the permanent mandibular left lateral incisor and canine (Md.L2.C), and development of a complete tooth transposition between the permanent maxillary right first pre-molar and canine (Mx.C.P1). The patient was treated in two phases. The first, in the mixed dentition, and the second, in the permanent dentition with a three-year follow-up between them. These challenging treatment approaches are described in detail, including the mechanics used. The key points of this treatment were early diagnosis of the ectopic mandibular lateral incisor, use of light forces and interphase patient follow-up. These determined the best time to start the second treatment phase, enabling achievement of aesthetic and functional outcomes, and the results remained stable one year after the end of orthodontic treatment.

Determining the Applicability of Moyer’s Analysis in the Contemporary Western Australian Adolescent Population

Background:Moyer’s probability tables have been widely used to determine the mesiodistal dimensions of unerupted canines and premolars for mixed dentition space analysis. Secular, racial, and sexual dimorphism have been reported in the literature and the applicability of Moyer’s analysis has been doubted in many other populations.Objective:The present study was conducted to determine the applicability of Moyer’s probability tables and develop a more accurate prediction method in a contemporary Western Australian adolescent population.Methods:A retrospective study, including 500 participants (323 females, 177 males) between 13-18 years old attending the orthodontic private practice, was conducted. Mesiodistal dimensions of selected participants were obtained from pre-orthodontic treatment digital dental records using Invisalign® technology (Invisalign®, Align Technology, Santa Clara, CA, USA). Data were analysed using SPSS. New regression equations were derived based on the sum of permanent mandibular incisors, and probability tables were proposed for more accurate prediction.Results:Significant differences were found between the measured sum of permanent canine-premolar segments and those predicted with the Moyer’s probability table, at all percentile levels, except the 50th percentile, where no significant difference was observed.Conclusion:Moyer’s probability table can be applied at the 50th percentile for estimation of sum of mesiodistal dimensions of canine-premolars segments. Newly developed regression equations and tables could be considered to provide more accurate mixed dentition space analysis.

Spontaneous Eruption of a Dilacerated Mandibular Central Incisor after Trauma of a Primary Tooth : Two Case Reports

Dilacerations generally involve central incisors; most often maxillary incisors rather than their mandibular counterparts. The clinical features of dilaceration include non-eruption of the responsible tooth or prolonged retention of the deciduous predecessor tooth. In Case 1, the tooth showed a dilaceration at the boundary between the crown and the root, more laterally rather than labiolingually. In Case 2, the dilacerated tooth showed a crown dilaceration with a relatively normal orientation of the dental root. In both cases, no significant space losses for eruption were observed. Moreover, it seems that unlike the maxilla with the palate, the mandibular anterior teeth are limited to show severe displacement. From these cases, it is suggested that if a mandibular permanent incisor shows a crown dilaceration or lateral dilaceration at the boundary between the crown and the root, there is a relatively high probability of spontaneous eruption of the dilacerated tooth.

Delayed Eruption of Permanent Lower Lateral Incisor in Relation to Compound Odontoma: A Case Report

To report a delayed tooth eruption following late surgical removal of a compound odontoma in a 10-year-old child. Odontomas are the most common odontogenic tumors. They are usually asymptomatic and discovered during routine radiographic examinations or during an assessment of delayed tooth eruption. Odontomas are classified into compound or complex based on the microscopic structure of dental tissues. Early diagnosis and surgical removal of odontomas is the keyword for favorable results. This paper describes a case of compound odontomas in a 10-year-old boy that prevented eruption of the permanent mandibular lateral incisor. Extraction of mandibular primary lateral incisors and surgical excision of the compound odontomas was performed. After 3 years of follow-up, at the age of 13 years, the permanent lateral incisor erupted and approached the occlusal plane. Late surgical removal of odontomas resulted in a delayed eruption of the affected teeth. Surgical removal of odontomas and regular follow-up to monitor the eruption of the affected teeth should be considered for the teeth with an open apex before considering orthodontic traction.

Sexual dimorphism using permanent maxillary and mandibular incisors, canines and molars: An odontometric analysis.

Introduction:Sex identification of skeletal remains is one of the prime factors employed in identification of an individual. Teeth, the most hard and stable human tissue, which is resistant to physical insults, serve as a valuable material for forensic, anthropological, odontologic and genetics. Among the four main attributes of biological identity, gender determination is usually the first step in the human identification process. Hence, the main objective of the present study was to assess the dimorphic status of mesiodistal (MD) width, labiolingual (LL) width as well as cervicoincisal (CI) length of the crown in both maxillary and mandibular permanent incisors, canines and first molars.Materials and Methods:The present study comprised a set of 100 casts (50 males and 50 females) between the age group of 20–50 years of age. Impressions were made using alginate impression and study models were prepared using dental stone. The CI length of the crown, maximum MD width and maximum LL width of both maxillary and mandibular permanent incisors, canines and first molars were evaluated using digital Vernier calipers. The obtained data were analyzed using linear discriminant analysis and logistic regression method.Results:This study concludes that MD dimension of maxillary canine and CI dimension of mandibular first molar as reliable indicators for gender determination than mandibular canine, maxillary and mandibular central incisors and maxillary first molar dimensions.Conclusion:This study concludes that MD dimension of maxillary canine and CI dimension of mandibular first molar as reliable indicators for gender determination than mandibular canine, maxillary and mandibular central incisors and maxillary first molar dimensions.

Early Management of Non-Syndromic Hypodontia in a Child: Three-Year Follow-Up

Hypodontia is the congenital absence of few teeth. The early multidisciplinary management of hypodontia assures the reestablishment of the disturbed psychological, aesthetic and oral functions. In this study, the clinical case of a child presenting a non-syndromic hypodontia with three agenesis teeth was described. No evidence of maxillary and mandibular third molars bud formation was noted on the orthopantomograph. To replace the two missing permanent mandibular central incisors, two mini-implants in the mandibular symphyseal region were placed and then restored by individually fixed prostheses. In the maxilla, the permanent canine in a complete transposition, was reshaped with composite resin restoration to replace the missing right permanent lateral incisor. Clinical and radiological reassessments were done 3 years later. The aesthetic and functional evaluations were satisfactory. The marginal bone level was stable with no bone loss. The periodontal health around the mini-implants were confirmed in conjunction with mechanical function.

Root and root canal morphology of permanent mandibular incisors in a Kuwaiti subpopulation: A cone-beam computed tomography study

Introduction: Sound knowledge of the external and internal anatomy of different teeth is an important prerequisite for successful endodontic treatment. The purpose of this in vivo study was to evaluate the root and root canal morphology of permanent mandibular incisors among a Kuwaiti subpopulation using cone-beam computed tomography (CBCT). Materials and Methods: A total of 600 Kuwaiti patients' CBCT images were screened and evaluated. A total of 1200 mandibular central incisors and 1200 lateral mandibular incisors were studied. The root canal morphology was recorded using Vertucci's classification and the association between the total number of root canals and patient's gender, tooth type (central vs. lateral incisor), and tooth location (right vs. left) were analyzed using Pearson's Chi-square test. Results: The prevalence of two canals in mandibular central incisors and lateral incisors was 24% and 27%, respectively. In both incisors, Type I root canal configuration was the most common (74.5%) followed by Types III and II. The total number of root canals per tooth was significantly higher in the central (P Conclusion: Within the limitations of this clinical study, Type I root canal configuration was the most common root canal configuration of the mandibular incisors. The prevalence of two canals was significantly higher in males compared to females.

Applicability of moyer's probability tables in north indian population of 16-18 years old.

To determine the applicability of Moyer's probability tables in North Indian population of 16-18 year olds and to formulate a new regression equation for the same group of population. Evaluative Study. 1000 children aged 16-18 years were selected as sample for the measurement of mesiodistal widths of permanent mandibular incisors, maxillary and mandibular canines and premolars using study models. The recorded values were then subjected to statistical analysis. Software Package for Social Sciences (SPSS) software version 22.0. The actual widths of the canine and premolars showed highly significant differences in maxilla and in mandible (P < 0.001), compared to widths predicted by Moyer's probability table at 75th percentile. Moyer's mixed dentition analysis was not an accurate method for prediction in North Indian population as it showed overestimation of tooth sizes. Hence, new regression equation has been formulated for the same.

Applicability of Boston University approach for predicting permanent teeth size in a sample of children

Background Accurate prediction of the mesiodistal widths of canines and premolars in children with primary dentition facilitates interception of malocclusion at an early age. Boston University (BU) approach is one, that is, based on primary teeth for predicting canine and premolar dimensions. Aim The aim was to evaluate the size of unerupted canines and premolars using BU approach in comparison to Tanaka and Johnston (T/J) analysis in a sample of Egyptian children. Materials and Methods A total of 300 children (150 boys and 150 girls) with an average age (7–10) years with existence of primary maxillary and mandibular canines and primary first molars and eruption of all permanent mandibular incisors, free from caries, restoration or any abnormalities in size, shape or structure of teeth. The mesiodistal widths of the required teeth were measured using digital caliper from which widths of permanent canines and premolars were predicted using both T/J analysis and BU approach. Results There was a strong positive correlation between BU approach and T/J analysis when used for children in mixed dentition stage. Conclusion Application of BU approach as a prediction method of permanent teeth dimension in a sample of Egyptian children from Tanta city in the mixed dentition stage revealed a strong correlation with the widely applied T/J analysis.

Evidence of Second Canal between Permanent Mandibular Central and Lateral Incisors in China; a Systematic Review on CBCT Studies.

Introduction Evidence of second canal in permanent mandibular incisors is frequently questioned in dentistry. The difference in evidence between the two teeth is an interesting argument across different countries and ethnicities. So the aim of the systematic review was to investigate the evidence of second canal between permanent mandibular central and lateral incisors in China. Materials and Methods The papers were selected from the electronic databases and hand searching according to inclusion and exclusion criteria. All qualified studies were judged by the reviewers. The selected studies were checked with Joanna Briggs Institute Critical Appraisal tool for prevalence studies. Finally, three studies were selected for the review and meta-analyses. The proportion of the second canal with its confidence interval and forest plot for the meta-analyses were calculated. Results The evidences of second canal in permanent mandibular central and lateral incisors in China were 5.6% and 14.1%. Only one study reported bilateral symmetry of the second canal as 58.7% and 76.1% in the two types of teeth. Out of all canal anatomies, Vertucci's type ΙΙΙ was dominant comprising 4.1% and 11.2% together with other second-canal types comprising 1.4% and 3% in permanent mandibular central and lateral incisors. When the proportions were meta-analyzed, mandibular central incisors had been less numerous OR = 0.35 [0.31, 0.40], 0.33[0.28, 0.39], and 0.42 [0.22, 0.79] in the evidence of second canal, of Type ΙΙΙ, and of other types except Type ΙΙΙ than mandibular lateral incisors in China. Out of all second-canal anatomies, Type ΙΙΙ presented 72.5% and 78.9% along with other second-canal types comprising 24.3% and 21.1% in the two teeth in China. Discussion. There was the evidence of second canal which deviated toward the permanent mandibular lateral incisor also in case of bilateral symmetry, the prevalence of Vertucci's Type ΙΙΙ, and other second-canal types out of all canal anatomies.

Hypericum perforatum L.: A Potent Antioxidant Source for the Treatment of Oxidized Dentin: An Experimental In Vitro Study

Aim: To evaluate the therapeutic antioxidant effect of Hypericum perforatum L. (HPL) extract on oxidized dentin as well as to address the following research question: Is experimental HPL-derived antioxidant treatment protocol as effective as sodium ascorbate in terms of reversing the compromised resin bonding to bleached dentin? Materials and Methods: Eighty bovine permanent mandibular incisors were included in the shear bond strength (SBS) test and randomly assigned into four groups ( n = 20) as follows: negative control (NC), positive control (PC), sodium ascorbate (SA), and Hypericum perforatum L. (HPL). Group NC did not receive bleaching treatment. All specimens except the NC group were oxidized by bleaching with 35% hydrogen peroxide. Experimental antioxidant solutions were prepared from SA powder and HPL extract at 10% concentrations. The bleached specimens in the SA and HPL groups were treated with respective antioxidant solutions. The SBS test was performed at a crosshead speed of 1 mm/min. The SBS data were analyzed with one-way analysis of variance using the post-hoc Bonferroni correction. The total phenolic content and the antioxidant activity of HPL extract were assessed by using the Folin–Ciocalteu assay and the 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging activity test, respectively. Results: Considering the SBS test results, statistically significant the highest and the lowest mean values were observed in NC and PC, respectively ( P &lt;.05). SA and HPL were not significantly different ( P &gt; .05). The total phenolic content (104 ± 1.740 mg gallic acid equivalents (GAE)/gram (GAE/g) dry HPL extract) and the antioxidant activity of the HPL extract were demonstrated. Conclusions: The natural HPL plant extract was as effective as SA in reversing the compromised resin bonding to bleached dentin. Antioxidant treatment derived from the HPL extract may enable immediate resin restoration of oxidized dentin.

Apical Debris Extrusion by Adaptive Root Canal Instrumentation in Oval Canals: Full-Sequence SAF System vs. the XP-Endo Shaper Plus Sequence

Apical extrusion of debris (AED) by the full sequence of the self-adjusting file (SAF) system was compared with that of the XP-endo shaper plus sequence. Sixty permanent mandibular incisors were randomly assigned to two groups (n = 30) for root canal instrumentation: Group A: Stage 1—pre-SAF OS, pre-SAF 1 and pre-SAF 2 files, followed by Stage 2—1.5 mm SAF; and Group B: Stage 1— hand K-file 15/0.02, followed by Stage 2—XP-endo shaper and Stage 3—XP-endo finisher. The AED produced during instrumentation at each stage was collected in pre-weighed Eppendorf tubes. The weights of AED by the two methods were compared using t tests with significance level set at 5%. Group A produced significantly less total AED than Group B (p &lt; 0.001), with no significant difference in debris extrusion between the two stages (p = 0.3014). Conversely, in Group B, a significant difference was noted between Stage 1 and Stages 2 and 3 (p &lt; 0.01), with no significant difference between Stages 2 and 3 (p = 0.488). Both sequences resulted in measurable amounts of AED. Each phase, in either procedure, made its own contribution to the extrusion of debris.

Case report on dentigerous cyst in relation to permanent mandibular lateral incisor: A rare entity

Dentigerous cyst is normally associated with crown of an unerupted or developing tooth and is one of the most common odontogenic cyst. It is more commonly seen in association with mandibular third molar and maxillary canine. Dentigerous cyst generally occurs in second or third decades of life. Its association with incisors are rare entity. Dentigerous cyst usually includes a tooth which can not complete the eruption process and involves the crown by the fluid accumulation in between the layers of enamel organ. The treatment modalities for dentigerous cyst are marsupialization or enucleation and depends upon the involved structures. Here we report a case of dentigerous cyst associated with permanent mandibular lateral incisor. It was enucleated along with the lingually erupted lateral incisor. There was no recurrence observed after one year follow up. Keywords: Dentigerous cyst, Odontogenic cyst, Lateral incisor, Marsupialization, Enucleation.

Root Canal Anatomy of Myanmar Permanent Mandibular Incisors in Mandalay Region.

Introduction Incomplete understanding of the root canal system leads to endodontic failure. Missed canal was the fourth most common endodontic failure, which needed retreatment. There were a few studies on internal morphology of posterior teeth of Myanmar population. However, there was no report on root canal anatomy of anterior teeth. So, the aim of the in vitro study was to investigate root canal anatomy of Myanmar permanent mandibular incisors in Mandalay Region by the staining and clearing method. Materials and Methods A total of 96 teeth from the tertiary hospitals and one academic department in Mandalay Region were selected according to inclusion and exclusion criteria. Then, they were cleaned, drilled, stained with Indian ink, and decalcified with 5% nitric acid for 3 days. After that, they were dehydrated with ascending concentration of ethanol (80% overnight, 90% for 1 hour, and full strength for three hours). Finally, they were clarified with 98% methyl salicylate and investigated by calibrated observer in case of Vertucci's classification, allocation of apical foramen, and the detailed anatomy. Result Almost 70% of the teeth had type Ι followed by 21.8% type ΙΙΙ, 4% 1-2-1-2-1 and type ΙΙ, and 1-3-2 and 2-3-1 comprised 1% each. Nearly 70% of apical foramen at central allocation of the root and 14% of detailed anatomy were seen in the sample teeth. Conclusion Most of the sampled Myanmar teeth comprised one canal and one foramen followed by type ΙΙΙ. However, unusual anatomies, such as 1-2-1-2-1, 1-3-2, and 2-3-1, were also seen. Contrastively, proportions of central location of apical foramen and of detailed anatomy were differed from the former reports. This study summarized that 3 in 10 mandibular incisors comprised the evidence of second or third canal configuration. Three types of intercanal calcifications, fusiform, islet, and bead, were additionally explored.

Evaluation of Tanaka and Johnston and Moyers Mixed Dentition Space Analysis in a Population of Mysore, India

Objectives: To evaluate applicability of Tanaka and Johnston (T&amp;J) and Moyer’s mixed dentition prediction methods and formulate regression equations for predicting mesiodistal widths of unerupted canines and premolars in Mysore population. Dental casts of 400 Mysore subjects aged 16-23years were used. Mesiodistal dimensions of mandibular permanent incisors, maxillary and mandibular permanent canines, first and second premolars were measured using a digital calliper calibrated to 0.01mm. Actual teeth measurements were then statistically compared with predicted values derived from T&amp;J’s equations and Moyers probability tables at 75th percentile. T&amp;J prediction equations overestimated mesiodistal widths of permanent canines and premolars in both arches. Moyers 75th percentile also overestimated actual measurements except for maxillary arch in female subjects. Percentage of overestimation was more for T&amp;J prediction method than Moyers. Regression equations and probability tables derived for tooth size prediction for Mysore population would be more accurate when applied locally.

Root Canal Morphology of the Permanent Mandibular Incisors by Cone Beam Computed Tomography: A Systematic Review

Knowledge of dental anatomy through the assessment of the anatomic variations of each tooth’s root canal system is essential to undertake endodontic therapy. The aim of this systematic review was to analyze the different studies on the internal morphology of permanent mandibular incisors where Cone-Beam Computed Tomography (CBCT) X-ray imaging is used. Pubmed, CENTRAL, Wiley Library and Web of Science electronic databases were searched for scientific studies included until March 2020. The terms used in the search were: “permanent mandibular incisors”, “root canal morphology” and “cone-beam computed tomography”. The search was limited to studies whose aim was the analysis of the morphology of the root canal system evaluating the parameters of methodology, population, sample, number and configuration. A total of 19 studies met the inclusion criteria. There was a noticeable lack of unanimity in the setting adjustments of each of the CBCT devices used. The presence of two root canals varied from 0.4% to 45%. The most frequent configurations were Vertucci’s Types I, III, II, V, IV, VII and VI. Type VIII configuration was non-existent. CBCT revealed the existence of anatomical symmetry patterns, and there was no unanimity of criteria regarding the presence of a second root canal. Results concerning the presence of a second root canal in the mandibular incisors differ widely, with a possible influence of the geographic area where the study was conducted. The prevalence of a second canal is higher in mandibular lateral incisors than in mandibular central incisors. There was no direct relationship between voxel size (0.125–0.3 mm) and increased prevalence of a second canal.

Authors' Comments—Long-Term Postoperative Cone-Beam Computed Tomography Analysis of Secondary Bone Grafting in 79 Patients With Unrepaired Alveolar Clefts

Authors' Comments—Long-Term Postoperative Cone-Beam Computed Tomography Analysis of Secondary Bone Grafting in 79 Patients With Unrepaired Alveolar Clefts

Evaluation of Enamel Roughness in Vitro After Orthodontic Bracket Debonding Using Different Methods of Residual Adhesive Removal.

The aim of the present study was to compare different techniques for resin remnant removal (RRR) after orthodontic bracket debonding and to evaluate alterations on the dental enamel caused by these methods. The null hypothesis tested was that there is no difference between RRR techniques in relationship the changes caused on the dental enamel. A total of 75 bovine mandibular permanent incisors were used in the study. Brackets were bonded and debonded in each tooth in two experimental regions. Five RRR techniques were used in the experimental groups (n=15): Group 1-diamond bur (6-bladed), Group 2-diamond bur (12-bladed), Group 3-diamond bur (30-bladed), Group 4-aluminum oxide sandblasting (AOS), and Group 5-Er:YAG laser. Enamel surface was evaluated using profilometry, and surface roughness analysis was performed at three time intervals: before bracket bonding, after RRR techniques, and after final polishing. Qualitative analyses of the enamel surfaces were performed using scanning electron microscopy. Multiblade burs showed the best results, and the 30-bladed bur created a less irregular enamel surface. AOS caused greater enamel wear, and Er:YAG laser caused more surface irregularity. The null hypothesis was rejected. The multiblade burs were the least harmful than the other techniques. Enamel surface roughness after using the 30-blade bur was similar to the original enamel. These results indicate that the type of bur tested (30-bladed) can be indicated to remove resin remnants after bracket debonding.

Treatment of peri-invagination lesion and vitality preservation in an immature type III dens invaginatus: a case report

BackgroundTo report a case of type III dens invaginatus associated with peri-invagination periodontitis in an immature permanent mandibular central incisor with open apex, in which only the invagination area was treated and vitality was preserved.Case presentationA 9-year-old boy was referred complaining of pain in the mandibular left central incisor. After radiographic examination, an invagination into the pulp chamber of the tooth associated with periapical radiolucency was detected. Endodontic access was performed and the orifice was identified under a dental operating microscope. The invagination area was chemo-mechanically cleaned. After 1 week, the invagination was obturated with mineral trioxide aggregate. During the 2-year follow up period, the tooth was asymptomatic. Radiographic examination revealed significant progression of periapical healing and root development in the main root canal of the tooth.ConclusionNon-surgical root canal treatment of the invagination may preserve pulp vitality, and continuous root development of the tooth.