Permanent Mandibular Incisors Research Articles

Easy Debonding of Ceramic Brackets Bonded with a Light-Cured Orthodontic Adhesive Containing Microcapsules with a CO2 Laser.

An easy debonding method for ceramic brackets using a light-cured Bis-GMA resin containing heat-expandable microcapsules and CO2 laser was investigated. Ceramic brackets are used frequently in orthodontic treatment because of their desirable esthetic properties. However, the application of heavy force to ceramic brackets in debonding can fracture the tooth enamel and ceramic brackets, causing tooth pain. In total, 60 freshly extracted bovine permanent mandibular incisors were divided randomly into 10 groups of 6 specimens each, corresponding to the number of variables tested. Ceramic brackets were bonded to bovine permanent mandibular incisors using an orthodontic bonding agent containing heat-expandable microcapsules at different levels (0-30 wt%) and resin composite paste, and cured by a curing device. The bond strengths were measured before and after CO2 laser irradiation, and the temperature increase in the pulp chamber in fresh human first premolars was also evaluated. With CO2 laser irradiation for 5 sec to the bracket, the bond strength in the 25% microcapsule group decreased significantly, to ∼0.17-fold, compared with that of the no-laser group (p < 0.05). The maximum temperature increase in the pulp chamber was 5.3°C with laser irradiation, which was less than the level that induces pulp damage. From these results, it seems likely that the combined use of a light-cured orthodontic bonding agent containing microcapsules and a CO2 laser is a simple debonding system for ceramic brackets, with less debonding time and enamel damage.

Complicated Root Canal Morphology of Mandibular Lateral Incisors Is Associated with the Presence of Distolingual Root in Mandibular First Molars: A Cone-beam Computed Tomographic Study in a Taiwanese Population

IntroductionThe aim of this study was to assess the root canal configurations in permanent mandibular lateral incisors (PMLIs) and the correlation between the root canal configurations of PMLIs with the appearance of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomographic (CBCT) imaging. MethodsA total of 1200 CBCT images (300 patients) of PMFMs and PMLIs were investigated. The frequency and distribution of DLRs in PMFMs along with root canal configurations of PMLIs were assessed ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMLIs with the appearance of a DLR in PMFMs. ResultsThe prevalence of PMFMs with a DLR was 24.3%, and the incidence of complicated root canal configurations in PMLIs was 25.0%. The most prevalent root canal systems of PMLIs were Vertucci types I (75%) and III (23.0%). The incidence of complicated root canal configurations in PMLIs was 19.5% in the non-DLR group (ie, no DLR was found on either side of the PMFMs), 33.3% in the unilateral DLR (Uni-DLR) group (ie, a DLR was found in 1 of the PMFMs [the left or right side] and a DLR was not found on the other PMFM), and 39.8% in the bilateral DLR (Bil-DLR) group (ie, a DLR was found in both the right and left PMFMs). After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMLIs in the Uni-DLR and Bil-DLR groups compared with the non-DLR group were 2.12 (P = .003) and 2.707 (P < .001), respectively. ConclusionsThe simultaneous appearance of DLRs in PMFMs and complicated root canal configurations in PMLIs is prominent in Taiwanese individuals. Clinicians should be aware of the correlation between the anatomic variants of PMFMs and PMLIs, which are important before endodontic treatment.

Evaluation of the relationship between crown size and root canal morphology of mandibular incisors by cone beam computed tomography (CBCT).

BackgroundThe main reason for the failure of endodontic therapy is the incomplete knowledge about the anatomical variation of root canals. One of the most important factors that leads to the failure of root canal treatment, is missed and untreated major root canals.Objectivewith respect to the complexity of mandibular incisors treatment and high prevalence of the second canal, and the possibility of the relationship between the crown size and the extra canal in these teeth, the aim of this study was to determine the relationship between crown size and root canal morphology in mandibular incisors with CBCT.MethodsIn this cross-sectional study, mandibular permanent incisors were randomly collected in Qazvin City, Iran, and were mounted in eight ternary groups on a plastic slot, using putty molding material. After preparation of Scot view, the samples were scanned by CBCT NewTom 5G. Afterward, the mesiodistal and buccolingual dimensions were measured by the software’s measurement tool with a precision within tenths of a millimeter. In the next stage, a multi-planar option and 400% magnification tool of the software were utilized to study axial and cross sectional views of each tooth to determine canal type. Data were analyzed employing one-sample Kolmogorov-Smirnov, Levene, independent- samples t-test and Roc curve by SPSS version 20.ResultsThe majority of mandibular incisors have a single canal (63.9% of them had type I canal system). In addition, 36.1% of the roots had two canals, among which, type III was the most common. The mean of maximum mesiodistal and buccolingual diameters in type III was significantly bigger than that in type I (p<0.05), but the means of crown size in the two canal types were not significantly different.ConclusionDespite increase in mesiodistal and buccolingual dimension in two canal mandibular incisors with type III canal system, their crown sizes (M-D/F-L index) were not significantly different, in comparison to single canal incisors.

Occurence of dentinal defects after root canal preparation with R-phase, M-Wire and Gold Wire instruments: a micro-CT analysis

BackgroundThis study aims to evaluate the frequency of dentinal defects after root canal preparation with the ProTaper NEXT, K3XF and WaveOne GOLD systems using microcomputed tomography.MethodsSixty permanent mandibular incisors with a single canal were selected. Inspection of the teeth was performed under a stereomicroscope (15x) to observe the presence of pre-existing cracks and fractures lines. Samples were divided into three experimental groups (n = 20): ProTaper NEXT (PTN), K3XF (K3XF) and WaveOne GOLD (WOG). Specimens were scanned through high-resolution microcomputed tomography before and after the preparation of the root canal. Subsequently, all the axial images were examined by two different methods to find possible dentinal defects. Furthermore, an analysis of each millimeter of ten apical millimeters was also performed. The absence or presence of dentinal defects was screened by 3 pre-calibrated blinded examiners.ResultsAfter analysing all 45,720 slices, dentinal defects were observed in 48,33% (22096 slices). PTN, K3XF and WOG groups represented 11,11% (5079 slices), 17,22% (7873 slices) and 20% (n = 9144) of the cross-sectional images, respectively. At 10 apical millimeters (600 slices), 33,33% (200 slices) presented some dentinal defects, representing 7,22% (43 slices), 13,33% (80 slices) and 12,77% (77 slices) of the cross-sectional images in the PTN, K3XF and WOG groups, respectively. All the dentinal defects presented in the postoperative images existed in the images prior to instrumentation.ConclusionsThere was no correlation between the preparation of a root canal using the PTN, K3XF and WOG systems and the formation of new dentinal defects.

Frontonasal dysplasia: oral features, restorative and orthodontic dental treatment in a child

Frontonasal dysplasia is a complex rare malformation, characterised by abnormalities involving the central portion of the face, especially the eyes, nose and forehead. It can manifest independently or associated with other abnormalities as part of some syndromes. The purpose of this case report was to describe a 5-year-old patient, diagnosed with frontonasal dysplasia. Among the abnormalities characterised with this disorder were ocular hypertelorism, broad nose tip with median notch, median facial cleft, bifid anterior skull, low set hairline, Poland's syndactyly and ankyloglossia. Consisted of behavioural management, oral hygiene instruction, prophylaxis, topical fluoride application, extraction of primary teeth, composite resin restorations and sealants in pits and fissures. Preformed metal crowns were also applied to the right and left primary maxillary second molars. Currently, the patient is 11years-old in the permanent dentition and therefore was referred for corrective orthodontic and periodontal treatments due to the persistence of gingival retraction of the permanent mandibular right central incisor. The treatment in this case was directed to the promotion of oral health and orthodontic corrections, which are of fundamental importance due to medical, physical and social limitations of children affected by this syndrome, hindering healing and rehabilitative treatment. Paediatric dentists should be included in multidisciplinary teams providing care to patients with special needs, improving their quality of life.

Congenitally Missing Permanent Mandibular Central Incisors and Maxillary Second Molars in Conjunction with a Supernumerary Mandibular Central Incisor

ABSTRACT Congenitally missing teeth are one of the most common dental anomalies which may be termed as dental agenesis. Polygenesis, the formation of one or more supernumerary teeth, occurs much less frequently than agenesis. Hypodontia and hyperdontia are regarded as the opposite dental developmental anomalies. However, their simultaneous presence in the same individual is a rare condition. A case of concomitant hypo-hyperdontia (CHH) is presented here, wherein a 20-year-old female has missing mandibular central incisors, maxillary second molars, and all the third molars. In addition, she has a malformed supernumerary tooth in the mandibular left anterior region. Documentation of such rare case reports is necessary as it helps in minimizing the clinicians' challenge in diagnosing such cases and thus helpful in providing a multidisciplinary approach in treating such patients. How to cite this article Gupta N, Kadu A, Marya CM, Nagpal R, Oberoi S, Dahiya V. Congenitally Missing Permanent Mandibular Central Incisors and Maxillary Second Molars in Conjunction with a Supernumerary Mandibular Central Incisor. J Oral Health Comm Dent 2017;11(2):44-47.

Esthetic recovery of permanent Mandibular Lateral Incisor using biological post after non-surgical healing of Periradicular Lesion: A Case Report

Esthetic recovery of permanent Mandibular Lateral Incisor using biological post after non-surgical healing of Periradicular Lesion: A Case Report

Early treatment of nonsyndromic oligodontia: a clinical case report

This report aims to describe the clinical case of a 10-year-old male patient (R.C.B.C.), presenting nonsyndromic oligodontia with maternal family trait and absence of 22 permanent teeth. Clinically, the patient had prolonged retention of some primary teeth and presence of permanent maxillary left central incisor, permanent mandibular right central incisor and four first permanent molars. Radiographically, only permanent maxillary second molars and mandibular third molars were developing, whereas all other germs of permanent teeth were missing. Treatment consisted of maxillary expansion followed by moving permanent maxillary left central incisor bucco-mesially, and rehabilitation of spaces with removable denture, where the main goal was to restore function and esthetic harmony. The case has been monitored for the past six years. Nonsyndromic oligodontia is a rare condition that poses significant functional and psychosocial difficulties. Treatment usually requires a multidisciplinary approach among which pediatric dentistry and orthodontics play a major role. In view of its complexity, treatment should be initiated as early as possible to minimize future functional and aesthetic issues. Dental implants are considered as definitive treatment of cases of oligodontia, however, until the patient reached the ideal age, other treatments to ensure aesthetics and function must be performed.

Root canal morphology and assessment of incidence, type, and position of isthmus in permanent mandibular central incisor in North Indian population: An in vitro study

Background and Objectives: Mandibular incisor's anatomy presents a challenge when making endodontic access because of its small size and high prevalence of two canals and isthmus within them. The main objective of this study is to evaluate the root canal anatomy and its aberrant morphology in mandibular central incisors. Knowing the variations in canal anatomy such as two canals, presence of isthmus, type, its prevalence, and position in the mandibular central incisors, which help improve the procedure of successful root canal treatment. Materials and Methods: One hundred and twenty extracted human mandibular central incisor teeth were collected. Two different studies have been performed. Sixty teeth were studied through tooth clearing and dye penetration technique. Teeth were decalcified with 5% nitric acid, dehydrated with increasing concentrations of alcohol and rendered clear by immersion in methyl salicylate. Hematoxylin dye was inserted in access cavity and canals. The samples were observed under dental operating microscope. These samples were evaluated for root canal morphology to assess its root canal configuration. Sixty teeth were studied through sectioning of apical 3 mm (1, 2, and 3 mm from the apex) simulating a surgical resection method was followed. The sectioned samples were observed under stereomicroscope for evaluating isthmus and its type. Results and Conclusion: Sectioning study showed that canal shapes varied from round to oval, long oval, and ribbon shaped, while the prevalence of isthmus was more at 3 mm section. Tooth clearing study showed that 46.6% teeth had single canal, 49.8% teeth had two canals, and only 5% teeth had two separate apical foramina.

Influence of dentin pretreatment on bond strength of universal adhesives

Objective: The purpose of the present study was to compare bond strength of different universal adhesives under three different testing conditions: when no pretreatment was applied, after 37% phosphoric acid etching and after glycine application.Materials and methods: One hundred and fifty bovine permanent mandibular incisors were used as a substitute for human teeth. Five different universal adhesives were tested: Futurabond M+, Scotchbond Universal, Clearfil Universal Bond, G-Premio BOND, Peak Universal Bond. The adhesive systems were applied following each manufacturer’s instructions. The teeth were randomly assigned to three different dentin surface pretreatments: no pretreatment agent (control), 37% phosphoric acid etching, glycine pretreatment. The specimens were placed in a universal testing machine in order to measure and compare bond strength values.Results: The Kruskal–Wallis analysis of variance and the Mann–Whitney test were applied to assess significant differences among the groups. Dentin pretreatments provided different bond strength values for the adhesives tested, while similar values were registered in groups without dentin pretreatment.Conclusions: In the present report, dentin surface pretreatment did not provide significant differences in shear bond strength values of almost all groups. Acid pretreatment lowered bond strength values of Futurabond and Peak Universal Adhesives, whereas glycine pretreatment increased bond strength values of G Praemio Bond adhesive system.

An In-Vitro Cone-Beam Computed Tomographic Evaluation of Root Canal Anatomy of Permanent Mandibular Incisor Teeth in an Indian Population

An In-Vitro Cone-Beam Computed Tomographic Evaluation of Root Canal Anatomy of Permanent Mandibular Incisor Teeth in an Indian Population

Disturbances and noise: Defining furrow-form enamel hypoplasia.

The investigation of the record of growth locked in dental enamel provides a unique opportunity to build a comprehensive picture of growth disruption episodes during childhood. This study presents a new methodological basis for the analysis of enamel growth disruptions (enamel hypoplasia) using incremental microstructures of enamel. A three-dimensional technique based upon use of an Alicona 3D Infinite Focus imaging microscope and software is used to record developmental features in the enamel of human permanent mandibular lateral incisors of one individual from the Neolithic site of Çatalhöyük (Turkey). Using this new technique, perikymata are measured down the longitudinal axis of the crown from the incisal margin to the cervix and perikyma spacing profiles are constructed with this new technique. A mathematical basis for the detection of spacing anomalies, which serve as indicators of enamel hypoplasia is presented based upon these profiles. Three clearly delineated defects were identified visually, then matched and confirmed metrically using the enamel surface and perikyma spacing profiles. Human growth has often been used as an indicator of health in past societies because of developmental sensitivity to fluctuations in nutritional status and disease load. Hence, standardization of furrow-form defect identification is of crucial importance for reducing the amount of current subjectivity in the determination of a threshold for the identification of defects among individuals of past populations. The method presented here, which is based on microscopic images of the tooth crown as well as recorded measurements of incremental structures, represents a combined visual-metric approach using LOWESS residuals, and as such provides a substantial advancement to previous methods. It is therefore recommended that additional studies be carried out with this methodology to determine whether this method improves the reliability of enamel defect identification among individuals recovered from bioarchaeological contexts.

Mixed dentition space analysis among Nepalese Brahmins/Chhetris

BackgroundMixed dentition space analysis forms an important part of orthodontic diagnosis and treatment planning. Regression equations are widely used for mixed dentition analysis which can vary among races. This study aimed to find out the new regression equation in estimating the size of unerupted canines and premolars for Nepalese Brahmins/Chhetris.MethodsHundred Nepalese Brahmins/Chhetris (50 males and 50 females) who met our criteria were selected among the patients attending to the Orthodontic Out-Patient Department, Institute of Medicine, Kathmandu. The mesiodistal widths of all mandibular permanent incisors; maxillary and mandibular canines and premolars were measured and analyzed. The results were also compared with predicted values from the Moyers and the Tanaka and Johnston methods. Correlation and linear regression analyses were performed between the predicted and actual tooth sizes for Nepalese Brahmins/Chhetris and standard regression equations were developed.ResultsNo significant differences were observed when the sum of canine and premolars of one quadrant is compared between sides and sex. Significant and high positive correlations were found between the mandibular incisors and the combined mesiodistal widths of the canines and premolars for the maxillary (r = 0.72) and mandibular (r = 0.73) segments. Significant differences were observed between the measured values from this study and from Moyers (50 % and 75 % probability) and Tanaka-Johnston methods.ConclusionsThe equations and charts commonly used for North American children (50th or 75th percentile) did not accurately predict for our sample, so new regression equations and tables were developed for Nepalese Brahmins/Chhetris children.

Current View on the Diagnosis and Treatment of Molar Incisor Hypomineralization

Molar incisor hypomineralization (MIH) is defined as the hypomineralization of one or more first permanent molars with or without the involvement of the maxillary and mandibular permanent incisors. Although the etiology of MIH remains unclear, several etiological factors, such as the genetic and environmental factors and systemic disturbance during pre-, peri-, and postnatal period, can cause enamel defects and their occurrence. The prevalence of MIH is reported to be between 2.4% and 25% in different communities. Teeth with MIH are extremely hypersensitive, prone to rapid caries development, and can be difficult to manage in young patients, and thus, dentists may have difficulties during diagnosis, treatment planning, and managing children with MIH during treatment. Early diagnosis is essential because rapid breakdown of tooth structure may occur, resulting in acute symptoms and complicated treatment. This study aimed to review the diagnosis and etiological factors involved in the occurrence of MIH and to evaluate treatment approaches in the management of MIH.

Mixed dentition space analysis in a Sudanese population.

To test the applicability of the Tanaka and Johnston equation for prediction of the mesiodistal width of unerupted permanent teeth in a Sudanese population and to develop a new prediction equation for this specific population if necessary. A descriptive, cross-sectional study. School-based study. Two hundred and fifty subjects (118 males and 132 females) age 13 - 19 years were randomly selected from two public secondary high schools in Khartoum State. Mesiodistal widths of the upper and lower permanent canines, first and second premolars (CPM) as well as the mandibular permanent incisors (MPI) were measured manually on the dental casts using a digital caliper. The predicted values of the mesiodistal widths were statistically compared with the respective actual sum of the canine and premolars of the same quadrant. Moderate correlation coefficients were found between the sum of the mesiodistal width of the MPI and the sum of the CPM in males (0.618 for mandibular arch and 0.626 for maxillary arch) and females (0.726 for mandibular arch and 0.680 for maxillary arch). A low coefficient of determination was recorded (0.45 and 0.48) in both jaws for combined genders. The Tanaka and Johnston equations overestimated the actual mesiodistal width of CPM in both arches for males and females. New prediction equations with more accurate regression parameters were proposed for the Sudanese population.

Morphology of Mandibular Incisors: A Study on CBCT

SummaryBackgroundThe aim of the study was to identify the number of root canals and examine root canal morphology of permanent mandibular incisors in an Indian sub-population of Pune, Maharashtra, India using cone-beam computed tomography (CBCT).Material/MethodsThis study was conducted at Elite CBCT & Dental Diagnostics, Pune. One hundred mandibular incisors were evaluated for the number of root, root canals and root morphology.ResultsIn the present study, amongst 102 mandibular incisors, all had one root, 36% of them had a second canal, and Vertucci Type I was the most common type.ConclusionsCBCT imaging is an excellent method for detection of different canal configurations of mandibular incisors.

Mixed Dentition Space Analysis in a Sudanese Population.

Objective: To test the applicability of the Tanaka and Johnston equation for prediction of the mesiodistal width of unerupted permanent teeth in a Sudanese population and to develop a new prediction equation for this specific population if necessary. Design: A descriptive, cross-sectional study. Settings: School-based study. Subjects and Methods: Two hundred and fifty subjects (118 males and 132 females) age 13 – 19 years were randomly selected from two public secondary high schools in Khartoum State. Mesiodistal widths of the upper and lower permanent canines, first and second premolars (CPM) as well as the mandibular permanent incisors (MPI) were measured manually on the dental casts using a digital caliper. The predicted values of the mesiodistal widths were statistically compared with the respective actual sum of the canine and premolars of the same quadrant. Results: Moderate correlation coefficients were found between the sum of the mesiodistal width of the MPI and the sum of the CPM in males (0.618...

Talons Cusps: The Achilles’ Heel of the Incisors

Abnormalities in tooth morphology are not uncommon. However talon's cusp is a recherche dental anomaly of the permanent dentition. It's an anomalous structure resembling an eagle's talon that projects lingually from the cingulum area of a maxillary or mandibular permanent incisor. Presence of bilateral talon's cusp in primary lateral incisors is an extremely recondite clinical finding. Its presence makes the otherwise caries resistant incisors prone to tooth decay. It is generally asymptomatic but sometimes it may pose functional or esthetic problems and so it demands a preventive line of management. This paper reports one such rare case of non-syndromic bilateral talon's cusp in primary lateral incisors during mixed dentition period and its preventive management.

Primary double teeth in siblings: A report

Double teeth are developmental malformations affecting both primary and permanent dentition. This article describes primary double teeth in both the siblings of a family. A 5-year-old boy had a bilateral distribution of anomaly involving lower lateral incisor and canine. Radiographic analysis revealed that his right mandibular permanent lateral incisor was missing. His sister, a 3½-year-old girl, also had double teeth affecting mandibular left lateral incisor and canine. She displayed no other dental anomaly. The boy presented shovel-shaped maxillary permanent central incisors. Family involvement of double teeth is very rare. Double teeth in siblings and simultaneous occurrence of multiple dental anomalies probably show a hereditary etiology.

Age estimation and eruption of permanent teeth between two genders-A cross sectional study

Identification is necessary in living persons, recently dead, decomposed bodies, mutilated bodies, skeletonised bodies etc. Age estimation constitutes one of the important tools for identification of a person, both in civil and criminal cases. Teeth are the most reliable material in identification and age estimation in the dead as they do not undergo mutilation by fire or decomposition A tooth is considered to be erupted when the crown or any part of the tooth becomes clinically visible in the oral cavity. The present study was conducted to collect the cross-sectional data for the time and sequence of eruption of permanent teeth among the school going children of north Indian population. The age group was limited to 6 to 14 years, which includes the age range at which all permanent teeth have been found to be erupted, except the third molars. Schools registered with Directorate of school education were considered for the study. A total of 1804 subjects were examined. The mean age of eruption of mandibular first molar has been found to be earlier than the permanent mandibular central incisor as well as earlier in females compared to males. Also the mean age of eruption of any tooth has been found to be earlier in mandible as compared to maxilla in both males and female. Permanent teeth erupted earlier in females than in males and also earlier in mandible compared to maxilla.