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Concept: Maxillary lateral incisor

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The aim of the study was to test the hypothesis that the gene defect causing congenital absence of maxillary lateral incisors also causes narrowing of the dentition. A total of 81 patients with one or two congenitally missing lateral incisors were retrieved; 52 (64.2 per cent) patients presented bilateral agenesis, whereas 29 (35.8 per cent) had unilateral agenesis. The control group consisted of 90 consecutively treated patients. The largest mesiodistal crown dimension for all teeth, except for the maxillary second and third molars, was measured on plaster casts using a digital caliper to the nearest 10th of a millimetre. Statistical testing was performed using the analysis of variance model (P < 0.05) to test for differences in the mesiodistal dimension between the sample and the control group. Significance has been assessed using a P-value threshold level of 5 per cent. Agenesis of maxillary lateral incisors was found to be a significant predictor of tooth size. Patients who were missing maxillary lateral incisors had smaller teeth compared to control subjects, except for the maxillary right and left first molars. This finding was true for both unilateral and bilateral lateral incisor agenesis. Interaction between maxillary lateral incisor agenesis and gender was not significant. Patients with congenitally missing lateral incisors have narrower teeth than patients without any dental anomalies, except for maxillary first molars. A higher prevalence of microdontic contralateral incisors was found in patients with unilateral agenesis with respect to the control group.

Concepts: Teeth, Analysis of variance, Molar, Incisor, Maxillary central incisor, Canine tooth, Maxillary lateral incisor, Mandibular lateral incisor

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Skulls (n = 1,205) of southern sea otters were examined macroscopically according to defined criteria. The museum specimens, acquired from strandings, varied in age from juvenile to adult, with an equal sex distribution. The results from all young adult and adult specimens were pooled according to tooth type. Ninety-two percent of teeth were available for examination, with 6.5% artifactually absent, 0.6% deemed absent due to acquired tooth loss and 0.03% deemed congenitally absent. All teeth were normal in morphology, except for three pairs of fused teeth, including two instances of fused maxillary first incisor teeth. Supernumerary teeth were associated with 97 normal teeth (most commonly maxillary canine teeth) in 68 specimens. At least one persistent deciduous tooth was present in six skulls, two of which were from adults. The majority (94.6%) of alveoli, either with or without teeth, were not associated with bony changes consistent with periodontitis; however, the majority (74.4%) of specimens did have at least one tooth associated with mild periodontitis. The mesial root of the mandibular third premolar tooth was the most common location at which periodontal hard tissue lesions were observed (56.6%). Ten sea otters had lesions consistent with focal enamel hypoplasia. Approximately half of the teeth (52.0%) were abraded; almost all adult specimens (98.1%) contained at least one abraded tooth, while fewer young adults were affected (76.4%). Tooth fractures were uncommon, affecting 1,343 teeth (4.5%). Periapical lesions were associated with 409 teeth (1.3%) in a total of 176 specimens, and these would likely have caused considerable morbidity while the animals were alive.

Concepts: Teeth, Tooth development, Incisor, Canine tooth, Maxillary lateral incisor, Premolar, Sea otter, Deciduous teeth

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External cervical resorption is the loss of dental hard tissue as a result of odontoclastic action; it usually begins on the cervical region of the root surface of the teeth. This case report demonstrates an external cervical resorption in a maxillary central incisor of a 24-year-old male patient. After surgical intervention and root canal treatment, the resorption was subsequently sealed with mineral trioxide aggregate. The 18 months follow-up demonstrates no pathological changes on clinical and radiographic examination. This case report presents a treatment strategy that might improve the healing outcomes for patients with external cervical resorption.

Concepts: Hospital, Mammal, Teeth, Endodontic therapy, Endodontics, Incisor, Maxillary central incisor, Maxillary lateral incisor

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- Primary tooth impaction is a rare phenomenon when compared to permanent teeth impaction. The purpose of this report is to present a 5-year-old Chinese girl who exhibited impaction of tooth 51, its unusual consequence on the permanent successor tooth and its comprehensive management. Her parents revealed that at 6 months of age, the patient had fallen from her bed and struck her face on the floor; however, there were no teeth present in the oral cavity. The intraoral examinations identified a bony-like projection on the buccal aspect of the alveolus in the 51 region. Radiographic examination revealed that tooth 51 exhibited an unfavourable orientation, with the crown directed towards the palate. Therefore, the impacted tooth 51 was surgically removed, and two years later tooth 11 erupted into the oral cavity with an indentation on its incisal aspect, which resembled the crown of the primary teeth, thus giving the appearance of a tooth within a tooth or ‘dens in dente’. Subsequently, enameloplasty and composite resin build-up was performed on tooth 11 for aesthetic reasons. It is very unusual to have the clinical crowns of both primary and permanent teeth in such close proximity within the alveolar bone, and the present case is a good example to emphasize that trauma to the primary teeth is of considerable importance due to the close proximity of the primary teeth to permanent tooth germs.

Concepts: Teeth, Incisor, Maxillary central incisor, Canine tooth, Maxillary lateral incisor, Deciduous teeth, Permanent teeth

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Introduction Knowledge of tooth dimensions and relationships and ethnic variations in these parameters are important in the planning and provision of aesthetic dentistry.Aim The aim of the present study was to investigate the dimensions and relationships of the upper anterior teeth in young adults of Indian origin, living in an urban location in the UK, and to compare the data obtained with data pertaining to other ethnic groups.Materials and methods This was a qualitative, non-experimental, cross sectional descriptive study with ethical approval. The dependent variables were tooth dimensions and relationships. The independent variable was gender. Fifty male and 50 female young adult Indians were recruited to the study, according to predetermined criteria. Upper and lower, full arch impressions were obtained for each of the 100 participants. Stone cast were obtained from these impressions. The width and length of each upper anterior tooth included in the casts were measured using precision callipers. Anterior arch length was determined using a flexible measuring tape. All measurements were repeated at least three times to obtain consistent values. The error of the method was investigated by means of repeat measurements. The data obtained was analysed, and compared with existing data on tooth dimensions and used to investigate the presence of Golden Proportion relationships.Results The measurements obtained had a normal distribution. Statistical analysis revealed significant differences in the overall data for left and right canine width and length (P <0.05). No such differences were noted in respect of the upper central and lateral incisors. Also, significant differences (P <0.05) were found to exist between male and female subjects in respect of the width of all anterior tooth types, except for the upper right lateral incisor. There were significant differences in the length of the upper left central incisor and upper right and left canines between male and female subjects (P <0.05). Significant differences (<0.05) were found in the width to length ratios between right and left canines. No such differences were observed for incisors. There was an absence of Golden Proportion relationships.Conclusion Within the limitations of the present study, it is concluded that it is inappropriate to adopt a formulaic, left/right symmetrical approach to smile design in the provision of aesthetic dentistry for young adults of Indian origin.

Concepts: Rodent, Teeth, Units of measurement, Incisor, Canine tooth, Golden ratio, Maxillary lateral incisor, Mandibular lateral incisor

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This in vivo study aimed to evaluate the efficacy of in-office and home teeth bleaching in Asian patients. Moreover, the correlation between tooth color change and patient’s outcome satisfaction was investigated. Overall, 40 Chinese patients were randomly divided into two groups and prescribed in-office (OB) or take-home bleaching (HB). The color of the maxillary central incisor and canine were recorded at baseline, immediately after first treatment, 1 week, and 3 months after treatment by using a spectrophotometer. Bleaching sensitivity and outcome satisfaction were assessed using Likert and visual analogue scale (VAS), and the results were analyzed using independent t-test and Pearson correlation (P < 0.05). ΔL*, Δa*, Δb*, and ΔE* values of HB were greater than those of OB. Color changes observed in canines were generally greater than those in incisors. Moreover, HB was generally associated with less tooth sensitivity than OB. Patients were satisfied with both treatments, but VAS scores were greater for HB. Furthermore, the correlation between ΔE* and VAS was significant for canines immediately after the first treatment and 1 week after HB. In conclusion, HB was more effective in lightening teeth and reducing chromacity in Chinese patients. The correlation between tooth color change and outcome satisfaction was generally insignificant and weak.

Concepts: In vivo, Rodent, Teeth, Incisor, Maxillary central incisor, Canine tooth, Maxillary lateral incisor, Premolar

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Fusion of teeth is a developmental anomaly. It occurs at the stage of tooth formation, which determines the shape and size of the tooth crown, when one or more teeth fuse at the dentin level during the morphodifferentiation of the dental germs. Such teeth show macrodontia and may cause crowding, as well as esthetic and endodontic problems. In this article, we report a rare case of a maxillary central incisor fused to a supernumerary tooth showing labial and palatal talon cusps, which was orthodontically moved across the midpalatal suture. A 13-year-old Caucasian boy sought treatment for the unesthetic appearance of his maxillary central incisor and anterior crowding. He was rehabilitated successfully via a multidisciplinary approach involving orthodontic, nonsurgical endodontic, periodontal, and prosthodontic treatments. After a 26-month treatment period, the patient’s macroesthetics and microesthetics were improved. The overall improvement of this macrodontic tooth and its surrounding tissues through multidisciplinary treatment was documented using cone-beam computed tomography.

Concepts: Teeth, Tooth, Tooth enamel, Incisor, Maxillary central incisor, Maxillary lateral incisor, Animal anatomy, American Dental Association

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To analyze and compare external apical root resorption (EARR) of maxillary incisors treated by intrusion arch or continuous archwire mechanics.

Concepts: Maxillary central incisor, Maxillary lateral incisor

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Several factors, including anomalies of shape, color, or size, or positioning of the teeth, may interfere with smile esthetics. A 26-year-old woman was dissatisfied with the esthetics of her maxillary lateral incisors, which had defective composite resin restorations with alterations of color and shape. The aim of this article is to present a step-by-step description of the technique used to fabricate esthetic restorations for the conoid maxillary lateral incisors with a minimum of dental preparation. The successful outcome demonstrates the importance of correct planning for successful restorations.

Concepts: Factor analysis, Composite material, Teeth, The Technique, Maxillary lateral incisor, Aesthetics, Dental composite