SciCombinator

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

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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: Maxillary lateral incisor, Tooth development, Sea otter, Deciduous teeth, Incisor, Premolar, Canine tooth, 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: Endodontics, Mammal, Maxillary lateral incisor, Maxillary central incisor, Incisor, Hospital, Endodontic therapy, Teeth

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

0

Achieving successful long-term esthetic outcomes in implant dentistry requires that the height and width of the facial or buccal alveolar bone wall and, subsequently, the peri-implant tissues be maintained. Partial extraction therapy (PET) can be used to reduce the risk of facio-lingual collapse after tooth loss and improve the preservation of alveolar bone height and blood supply. This article demonstrates the use of PET for treatment of a hopeless tooth in the esthetic zone. After removal of the fractured maxillary central incisor, an implant was placed and restored with excellent esthetic, functional, and periodontal results.

Concepts: Blood, Canine tooth, Maxillary lateral incisor, Heart, Maxillary central incisor, Dental implant, Incisor, Teeth

0

In this case report, we share a conservative and simple restorative management approach for a relatively complex esthetic situation on an adult patient with an ankylosed maxillary central incisor in infra-occlusion. A 37-year-old healthy female patient presented for a consultation with a chief complaint of an unappealing smile. The intraoral exam revealed tooth #8 (FDI 11) was in obvious and significant infra-occlusion due to altered eruption. Periapical radiographs of this area were non-contributory and all teeth responded within normal limits to pulp vitality tests. After review of several treatment options, the patient opted for a conservative restorative approach in which a partial ceramic veneer was planned for the ankylosed tooth, while composite resin was used on the contralateral central incisor to achieve a symmetric and pleasant result.

Concepts: Canine tooth, Maxillary lateral incisor, Maxillary central incisor, Incisor, Teeth

0

This case describes a female patient with agenesis of the maxillary right lateral incisor, with her permanent canine in its position and the deciduous canine retained. Additionally, she presented with a maxillary left peg lateral incisor. To solve her functional and esthetic complaints, a multidisciplinary approach involving perio-restorative procedures was proposed. Periodontal surgeries were performed to align the gingival contour, and the restorative approach utilized ceramic veneers. At the 18-month clinical and radiographic follow-up, the treatment outcome was stable, with maintenance of the clinical results achieved and without any sign of deciduous tooth resorption.

Concepts: Maxillary lateral incisor, Teeth, Canine tooth

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Labial grooves in maxillary incisors have been reported in several wild-type rodent species. Previous studies have reported age-dependent labial grooves occur in moderate prevalence in C57BL/6 mice; however, very little is known about the occurrence of such grooves. In the present study, we observed age-dependent groove formation in C57BL/6 mice up to 26 months after birth and found that not only the frequency of the appearance of incisor grooves but also the number of grooves increased in an age-dependent manner. We examined the molecular mechanisms of age-dependent groove formation by performing DNA microarray analysis of the incisors of 12-month-old (12M) and 24-month-old (24M) mice. Amelx, encoding the major enamel matrix protein AMELOGENIN, was identified as a 12M-specific gene. Comparing with wild-type mice, the maxillary incisors of Amelx-/- mutants indicated the increase of the frequency and number of labial grooves. These findings suggested that the Amelx gene impacts the age-dependent appearance of the labial incisor groove in C57BL/6 mice.

Concepts: Maxillary lateral incisor, Microarrays, Incisor, Maxillary central incisor, DNA microarray, DNA, Gene, Rodent

0

The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.

Concepts: Implants, Canine tooth, Maxima and minima, Maxillary lateral incisor, Engineering, Maxillary central incisor, Incisor, Finite element method

0

The use of the direct fiber-reinforced fixed dental prosthesis (FDP) restorative technique presented in this article will result in an ideal restoration considering both esthetics and function in a single appointment. Although indirect techniques are available and may be used, they are time-consuming, resulting in higher cost; therefore, a simplified approach combining a prebonded fiber-reinforced mesh with a sculptable micro-hybrid composite will deliver an acceptable esthetic result with proper function.

Concepts: Romance languages, Prosthetics, Maxillary lateral incisor, Maxillary central incisor, Teeth, Incisor