Maxillary tooth transpositions: characteristic features and accompanying dental anomalies.

Transposition is a dental anomaly manifested by a positional interchange of 2 permanent teeth. The maxillary permanent canine usually transposes with the first premolar and occasionally with the lateral incisor. The records of 65 orthodontically treated individuals with maxillary tooth transpositions (40 females and 25 males) with an age range of 9 to 25 years (mean age, 13.4 years) were studied to determine the distribution of transposition and to evaluate the accompanying dental anomalies. Thirty-six individuals (55%) had a transposition of the maxillary canines and first premolars, 27 (42%) of the canines and lateral incisors, and 2 (3%) of the central and lateral incisors. Females had 60% more transpositions than did males. Substantially more transpositions were unilateral (88%), with a moderate left side dominance (58%). All dental anomalies associated with transposition--including missing lateral incisors and second premolars, undersized lateral incisors, retained deciduous canines, impaction of permanent canines and central incisors, and severely rotated adjacent teeth--were observed on the side of the transposition. This dominance of the affected side suggested that unknown local factors may play a major role in these dental anomalies.     

Long-term follow-up of conservative treatment of severely traumatized maxillary incisors

Abstract We present the case of a 26-year-old man who at the age of 9 suffered severe trauma to both maxillary central incisors. The underlying malocclusion was skeletal and classified as dental Class II/1 with severe crowding. Both the maxillary central incisors and the two lower first premolars were extracted and the patient was treated with an edgewise appliance for 2 years. Acceptable occlusal relationships were achieved following orthodontic and adjunctive treatment which consisted of reshaping the maxillary lateral incisors with composite materials and grinding the canines to resemble lateral incisors. A critical evaluation of the esthetic and functional results at the age of 26 years is presented.     

Half nose with ipsilateral eye and ear anomalies and facial asymmetry: report of a case with cephalometric analysis and orthodontic treatment.

OBJECTIVE: Unilateral nostril agenesis together with ipsilateral alterations of the eye, ear, and face make up a spectrum of anomalies. The aim of this study is to report a case in a Japanese girl, 14 years, 5 months of age. Cephalometric analysis is provided, and orthodontic treatment is discussed. DESIGN: Lateral and frontal cephalograms were compared to a Japanese control group. Outcome of the orthodontic treatment was evaluated by comparing cephalograms taken before and after orthodontic treatment. RESULTS: The lateral cephalometric analysis showed a severely hypoplastic maxilla in both sagittal and vertical dimensions, coupled with a decreased posterior cranial base. The mandibular rami were asymmetric. The frontal cephalogram showed decreased cranial width and maxillary alveolar width, together with an increased interorbital distance. CONCLUSIONS: Serial lateral cephalograms during the orthodontic treatment from the age of 14 to 20 years demonstrated no significant maxillary growth and some mandibular growth, coupled with labial tipping of the maxillary central incisors.     

Anatomic crown width/length ratios of unworn and worn maxillary teeth in white subjects

STATEMENT OF PROBLEM: Dimensions of teeth have been available for a century. Some significant and clinically relevant aspects of dental esthetics, however, such as the crown width/length ratios, have not been presented in tooth morphology sources until recently. PURPOSE: The purpose of this study was to analyze the anatomic crowns of 4 tooth groups (central incisors, lateral incisors, canines, and first premolars) of the maxillary dentition with respect to width, length and width/length ratios and determine how these parameters are influenced by the incisal edge wear. MATERIAL AND METHODS: Standardized digital images of 146 extracted human maxillary anterior teeth from white subjects (44 central incisors, 41 lateral incisors, 38 canines, 23 first premolars) were used to measure the widest mesiodistal portion "W" (in millimeters) and the longest inciso-cervical/occluso-cervical distance "L" (in millimeters). The width/length ratio "R" (%) was calculated for each tooth. A 1-way analysis of variance was used to compare the mean values of W, L, and R for the different groups ("unworn" and "worn" subgroups, except for premolars). Multiple least significant difference range tests (confidence level 95%) were then applied to determine which means differed statistically from others. RESULTS: There was no influence of the incisal wear on the average value of W (width) within the same tooth group. The widest crowns were those of central incisors (9.10 to 9.24 mm) > canines (7.90 to 8.06 mm) > lateral incisors (7.07 to 7.38 mm). Premolars (7.84 mm) had similar width as canines and worn lateral incisors. The L-value was logically influenced by incisal wear (worn teeth were shorter than unworn teeth) except for lateral incisors. The longest crowns were those of unworn central incisors (11.69 mm) > unworn canines (10.83 mm) and worn central incisors (10.67 mm) > worn canines (9.90), worn and unworn lateral incisors (9.34 to 9.55 mm), and premolars (9.33 mm). Width/length ratios also showed significant differences. The highest values were found for worn central incisors (87%) and premolars (84%). The latter were also similar to worn canines (81%), which constituted a homogeneous group with worn lateral incisors (79%) and unworn central incisors (78%). The lowest ratios were found for unworn canines and unworn lateral incisors (both showing 73%). CONCLUSIONS: Along with other specific and objective parameters related to dental esthetics, average values for W (mesiodistal crown dimension), L (inciso-cervical crown dimension), and R (width/length ratio) given in this study for white subjects may serve as guidelines for treatment planning in restorative dentistry and periodontal surgery.     

Root curvature: differences among dental morphotypes and modifications after mechanical instrumentation

BACKGROUND: This study was designed to describe a method for measuring root curvature of extracted teeth, compare root curvature of four different dental morphotypes before mechanical instrumentation, and measure root curvature after mechanical instrumentation. METHODS: Fifty-five maxillary (14 central incisors, 13 lateral incisors, 14 cuspids, 14 premolars) extracted teeth were analyzed. Measurements were recorded on the horizontal plane at the most apical point of the cemento-enamel junction (CEJ). A 4 mm wide root portion on the buccal aspect was selected and recorded on this plane. A digital scanner traced the circle coinciding with the profile of this root portion and calculated its radius, arc, chord, and arrow (i.e., the perpendicular bisector of the chord). Since root curvature is the inverse of the radius (1/r), the radius was related to root curvature; the arc to the mesio-distal dimension of the root portion; and the reduction of the arrow to root flattening after mechanical instrumentation. The measurements were recorded four times: before treatment (baseline), after polishing, after a first root planing, and after a second root planing. The radii of each dental morphotype (upper central incisors, upper lateral incisors, upper canines, upper premolars) recorded in the first measurement were calculated and used for the statistical analyses: one-way analysis of variance (ANOVA) test and the Tukey multiple comparison method were used to study the curvature. The measurements of the radius, the arc, and the arrow at the four times were used for the statistical analyses: the two-way ANOVA test and the Tukey multiple comparison method were applied in the study of the root modifications after mechanical instrumentation. The accuracy and reliability of the method were also evaluated. RESULTS: The mean radii of the four dental morphotypes were: central incisors: 3.613 +/- 0.258 mm; lateral incisors: 2.558 +/- 0.256 mm; canines: 2.822 +/- 0.238 mm; and premolars: 2.321 +/- 0.179 mm. The statistical analyses revealed differences among central incisors, canines, lateral incisors, and premolars. There was no statistically significant difference between lateral incisors and premolars. Regarding the root modifications after mechanical treatment, the radius did not show statistically significant differences in any of the comparisons. The arc and the arrow did not show significant differences between baseline and polishing, while they did show significant differences after the second root planing. CONCLUSIONS: This study indicates that: 1) the method of measuring is accurate and reliable; 2) there are statistically significant differences among the root curvatures of different dental morphotypes; and 3) polishing did not modify the root. A vigorous root planing did not modify root curvature, but it did reduce the mesio-distal dimension and flatten the root surface slightly.     

Dental abnormalities in permanent dentition in children with submucous cleft palate

Seventy-three children with submucous cleft palate (38 girls and 35 boys), mean age 8.2 years (range 7.7-9.5), were studied retrospectively from orthopantomograms. Dental abnormalities in permanent dentition were found in 26 patients (36%). Missing teeth, mainly lower 2nd premolars, upper lateral incisors, and upper 2nd premolars, were found in 12 patients (16%). Most of the patients had 1 or 2 missing teeth, 2 had 3 missing teeth. In 5 patients hypodontia was associated with another dental abnormality. Other dental abnormalities included peg-shaped lateral incisors in 7 patients (10%), ectopic eruption of upper 1st molars in 6 patients (8%), transposition of upper canines and 1st premolars in 3 patients (4%), supernumerary teeth in 2 patients (3%), and palatally displaced upper canines in 1 patient (1%). As children with submucous cleft palate have a tendency towards increased frequency of missing teeth and other dental abnormalities, the need for thorough clinical and radiological dental examination is emphasized.     

Growth hormone receptor gene is related to root length and tooth length in human teeth

Objectives:To examine the relationship between tooth length and growth hormone receptor (GHR) gene variants in a healthy Japanese population.Materials and Methods:The subjects consisted of 193 Japanese adults (69 men, 124 women), aged 13 to 56 years. Genomic DNA was extracted from saliva and genotyped GHR rs6184 and rs6180 variants using the Taqman genotyping. Computed tomography (CT) images were acquired using a dental cone-beam CT scanner and reconstructed using open-source OsiriX medical image processing software. The maxillary (upper; U) and mandibular (lower, L) central incisors (1), lateral incisors (2), canines (3), first premolars (4), second premolars (5), first molars (6), and second premolars (7) were evaluated. Teeth were assessed for crown height (CH), root length (RL), overall tooth length (C+R), and crown to root ratio (C/R). The relationships between GHR variants and CH, RL, C+R, and C/R were statistically examined.Results:The GHR variant rs6184 was associated with the root lengths and tooth length for the upper and lower lateral incisors and upper canines (U2 RL; U3 RL, C+R; L2 RL [P < .05]).Conclusions:The results indicate that the GHR rs6184 variant is associated with tooth length and ratio dimensions in a Japanese cohort. Further studies utilizing a larger sample size are needed to confirm this finding.     

Interrelation of tooth crown diameters

The purpose of this study was to clarify the interrelation of the tooth crown diameters using statistical methods. The material consisted of 414 dental casts from orthodontic patients in the Japanese female. The mesiodistal diameters of all permanent teeth on the left side were measured, excluding the third molars. These values were examined by correlation coefficient matrix and multivariate analyses such as multiple regression, principal component and canonical correlation, etc. The results were as follows: 1) The tooth crown diameters showed a strong intercorrelation within each jaw and between both jaws. 2) When the incisors and the canine were large in size, the premolars and the molars tended to be small. 3) When the incisors and the molars were large in size, the canine and the premolars tended to be small. 4) When the incisors and the premolars were large in size, the canine and the molars tended to be small. 5) All of the teeth except the upper lateral incisor were classified according to size into the four groups of incisors, canines, premolars and molars. 6) The dentition with small teeth tended to show a spaced arch.     

恒尖牙双尖牙近远中径预测方程

目的：为口腔正畸临床混合牙列间隙分析提供简捷,便利的诊断依据。方法：在模型上测量牙冠近远中径,对测量值进行直线回归与相关分析。结果：下切牙与尖牙,双尖牙近远中径存在直线相关关系。结论：建立了汉族人群上,下颌尖牙双尖牙近远中径观测方程。     

Apical Root Resorption after Lingual Orthodontic Therapy

PURPOSE: Apical root resorptions are among the undesirable side effects of orthodontic therapy. The aim of the present study was to investigate radiologically whether and to what extent resorptions occur in patients treated solely with a fixed lingual appliance, as well as the pathogenetic relevance of the extent and direction of the therapeutically induced apical movement. PATIENTS AND METHODS: The collective comprised 33 female and seven male patients with a mean age of 24.2 +/- 8.4 years. Permanent lower premolars were extracted in five, and permanent upper premolars in 22 patients. In total, 456 upper and lower incisors and canines were assessed. In order to evaluate the relative change in root length and the sagittal and vertical apical movements, pre- and posttherapeutic panoramic radiographs and/or lateral cephalograms were analyzed. RESULTS: After completion of orthodontic treatment the mean root length was 96.3%, corresponding to a resorption rate of 3.7%. The resorption rates of teeth 11, 12 and 21 differed significantly from those of teeth 31, 32 and 43. Upper incisors presented increased mean resorption rates < or = 10%. Only 18% of the 456 teeth analyzed were affected by pronounced resorptions > 10%. 82% of the teeth were resorption-free. A patient-related evaluation revealed that 26 of the 40 patients had no resorptions > 20%, while 14 had between one and four affected teeth. No significant relationship between extent of resorption and parameters such as age, gender, active treatment time, Angle class, or extent and direction of apical movement was recorded. CONCLUSIONS: The results suggest that lingual orthodontic therapy resulted in only slight root resorptions. Pronounced root shortenings were observed in some patients whose individual predisposition may constitute the main risk factor for the occurrence of root resorptions.     

上颌阻生尖牙牵引治疗后邻近切牙牙根吸收情况的研究

目的 分析上颌阻生尖牙正畸牵引治疗后邻近切牙的牙根吸收情况及可能的相关因素。方法 选取上颌尖牙阻生且符合标准的43例患者,年龄10～23岁,共60颗上颌埋伏阻生尖牙。上颌阻生尖牙正畸牵引治疗前后分别拍摄锥形束CT,分析阻生尖牙邻近切牙的牙根吸收程度,并对可能存在的相关因素进行分析。结果 上颌阻生尖牙正畸牵引治疗后,上颌中切牙发生轻、中、重度牙根吸收的概率分别为71.7%、15.0%、13.3%,上颌侧切牙发生轻、中、重度牙根吸收的概率分别为48.3%、36.7%、15.0%,上颌中切牙与侧切牙牙根吸收严重程度存在差异(P<0.05)。位于腭侧及颌骨内、低位且靠近面中线的阻生尖牙,在正畸牵引治疗后,侧切牙牙根吸收程度较重(P<0.05)。低位阻生尖牙牵引治疗后,中切牙牙根吸收较重(P<0.05)。牵引时间较长时,中切牙牙根吸收程度较重(P<0.05)。治疗前已发生牙根吸收的切牙,在阻生尖牙牵引治疗后发生的牙根吸收程度较重(P<0.05)。结论 上颌侧切牙在阻生尖牙正畸牵引治疗后,发生的牙根吸收程度较重。上颌阻生尖牙正畸牵引治疗后,邻近切牙牙根吸收情况与阻生尖...     

Average arch widths and associated changes between initial, post-treatment and post-retention measurements

Computer image monitoring was used for evaluation of dental arch changes. A new special device captured geometrically calibrated images permitting comparison of several different dental casts. In the first part of this study 792 sets of study casts were screened. Measurements of dental arch width between reference points of canines, first premolars and first molars were made: upper jaw: men: canines: 35.1 +/- 0.13 mm; first premolars: 37.5 +/- 0.13 mm; first molars: 48.1 +/- 0.19 mm; women: canines: 33.4 +/- 0.13 mm; first premolars: 35.6 +/- 0.15 mm; first molars: 46.7 +/- 0.19 mm. In the second part of the study, changes between initial, post-treatment and post-retention alignment (5-years after orthodontic therapy) of upper and lower dental arch of 36 subjects were analyzed. Upper and lower arch compression in first premolars and molars area was visible before treatment. We conclude that computer image monitoring can be used for evaluation of dental arch changes during the different steps of treatment.     

Tooth anomalies associated with failure of eruption of first and second permanent molars

The occurrence of tooth anomalies in association with failure of the first and second molars to erupt was assessed in a sample of 1520 nonsyndromic subjects with uncrowded dental arches (mean age, 14 years 4 months) and compared with the prevalence rate calculated in a matched control group of 1000 subjects. The tooth anomalies examined included infraocclusion of deciduous molars, palatal displacement of maxillary canines, rotation of maxillary lateral incisors, aplasia of second premolars, and small size of maxillary lateral incisors. Associations among arrested eruption of first and second permanent molars and anomalies in tooth eruption and position (infraoccluded deciduous molars, palatally displaced canines, rotated maxillary lateral incisors) were highly significant (P <. 001). No significant association was found among the occurrence of molar eruption disturbances, aplasia of premolars, and small-sized laterals. These findings point to a common biologic cause for the appearance of failure of eruption of molar teeth and other disturbances in tooth eruption and position, most likely under genetic influence.     

Dental Findings in Patients with Ectodermal Dysplasia

BACKGROUND: Ectodermal dysplasia is an inherited disease causing malformations of all tissues originating from the ectoderm. The significance of this disease lies in severe hypodontia, and an accompanying hypoplasia of the alveolar process. The clinical situation is aggravated by a significant xerostomia. It was the aim of this study to document the distribution of hypodontia and tooth malformation. Furthermore, we aimed to elucidate the clinical impact of these findings. PATIENTS AND METHODS: Records of 30 patients (19 males, 11 females) suffering from ectodermal dysplasia were included. Their age ranged between 7 and 23 years. All patients had been examined clinically and radiographically. In every patient, a record was made of which teeth were missing or malformed, and which deciduous teeth persisted. Additionally, the entire treatment procedure was assessed. RESULTS: The third molars were missing in all of the patients. The number of aplastic permanent teeth ranged from 2 to 26. The maxillary lateral incisors were most frequently absent, followed by the mandibular central incisors. The most stable teeth were the central incisors of the upper jaw, and the canines and first molars in both jaws. However, the maxillary central incisors and canines were the teeth most affected by malformation. Deciduous canines and second molars were the most often persisting teeth due to agenesis of the maxillary lateral permanent incisors and mandibular second premolars. In two-thirds of the patients, missing teeth were replaced by removable dentures. Half of the patients received orthodontic treatment. CONCLUSIONS: Hypodontia and malformation are almost regular dental characteristics in patients suffering from ectodermal dysplasia. The distribution of absent teeth deviates remarkably from the general population. Treatment requires an interdisciplinary approach including orthodontics, prosthodontics and oral surgery.     

Severe hypodontia in a set of triplets

Hypodontia is the developmental absence of one or more teeth from the dentition and constitutes one of the most common developmental anomalies in humans with a reported prevalence of 1.6 to 9.6% in the permanent dentition. Hypodontia may occur in association with other genetic diseases, or as an isolated familial or sporadic form. This article describes the rare phenomenon of severe hypodontia in a set of triplets. The triplets presented with congenital absence of the second molars, second premolars in all quadrants and lower central incisors. An additional five teeth (upper canines, upper lateral incisors and upper left first premolar) were missing in one of the triplets. The treatment plan and the possible genetic mode of inheritance are discussed.     

Multidisciplinary solution for an avulsed upper central incisor: case report

Abstract – This case report refers to an 18‐year‐old female who suffered from dental trauma when she was 7 years old caused by a bicycle accident. Her maxillary right central incisor was avulsed, and the left one was extrusively luxated. The left central incisor was correctly repositioned and immobilized with a semi‐rigid splint. The right one could not be found. She presented with class II malocclusion and severe negative arch‐length discrepancies in both arches. The treatment objectives were the following: recover smile esthetics by replacing the maxillary right central incisor, correct the class II relationship, and optimally reduce mandibular and maxillary crowding. Extractions of the maxillary left lateral incisor and the lower right first bicuspid were performed; thus, the maxillary right lateral incisor would function as a maxillary right central incisor, the canines would function as lateral incisors, and the first bicuspids would function as canines. This allowed for the malocclusion to be corrected while simultaneously reestablishing the smile esthetics, without the use of an osseointegrated implant. A good occlusion with coincident upper and lower midlines was achieved. After orthodontic therapy, the patient underwent periodontal surgery to improve her gingival margins. Subsequent teeth bleaching was performed, and the patient received six porcelain veneers. A combination of orthodontic space closure and prosthetic rehabilitation may be the best treatment option after severe traumatic tooth loss.     

Prevalence of congenital hypodontia in the permanent dentition and its treatment

Congenital aplasia (agenesis) is an important development dental anomaly. There is a big discrepancy between the data on the prevalence of aplasia in dental literature. The authors analyzed orthopantomograms of 1875 children and adolescents at the Department of Dentistry for Children and Orthodontics of Semmelweis University. The prevalence of congenital aplasia was found 15.68% (294 subjects). There was no difference between the sexes. The most frequently missing teeth were the upper lateral incisors, the lower second premolars, the upper second premolars and the lower central incisors. The highest number of aplasia was detected in the second premolars (330 teeth). The frequency of aplasia of the molars was 0.74%. Oligodontia was found in 1.12%. The authors present two patients with aplasia and the successful treatment of the cases.     

Labially impacted maxillary canines causing severe root resorption of maxillary central incisors

This is a case report of a patient with bilateral labial impaction of maxillary canines causing pressure resorption on the lateral aspects of the maxillary central incisors. The orthodontic treatment plan included extraction of the impacted canines, positioned between the central and the lateral incisors. Six years after the orthodontic treatment, the affected central incisors remained asymptomatic.     

Supernumerary and supplemental teeth: case report

AIM: This is to report the case of a ten year old child affected by a numeric dental anomaly showing the pathologic condition characterised by the simultaneous presence of supernumerary and supplemental teeth. The anomaly was analysed to plan the best surgical and orthodontic treatments. CASE REPORT: Dental history, clinical and instrumental examinations were made to perform a correct orthodontic examination and diagnosis. A young patient was affected by numeric dental anomaly in the upper jaw. We observed a high number of teeth, specifically two normally formed supplemental lateral permanent incisors and an unerupted mesiodens placed between the upper central incisors. Firstly, the supplemental lateral teeth were extracted. This surgical therapy and the application of a space maintainer were made to permit the eruption of the permanent canines. Then the mesiodens also underwent surgical treatment (i.e. extraction). Eventually, physiologic eruption of permanent teeth was allowed by the planned surgical-orthodontic treatment. DISCUSSION: Aim of the surgical-orthodontic treatment was extraction of the unerupted supernumerary teeth to obtain the physiologic eruption of the permanent ones. Orthodontic treatment is important to solve malocclusions and maintaining the space for the eruption of permanent teeth. CONCLUSION: Aesthetics and function are two important parameters in modern dentistry. All clinicians should try to make a correct and rational diagnosis for both simple and complex dental pathologies. Particularly in young children, invasive and surgical disinclusive techniques can be substituted by interceptive orthodontic treatments.     

Dentoskeletal features associated with unilateral or bilateral palatal displacement of maxillary canines

The aim of the present study was to analyze the prevalence and distribution of palatally displaced maxillary canines (PDC) in a large orthodontic population, and to investigate the associations between PDC, craniofacial features, and other dental anomalies such as aplasia or small-sized upper lateral incisors. An initial sample of 5000 subjects was evaluated. The reference values were calculated in a control group of 1000 subjects that was extracted from the initial sample. Chi-squared tests were used for statistical comparisons. The prevalence rate of PDC was 2.4%, with a male-to-female ratio of 1:3. PDC subjects with low angle vertical relationships showed a significantly high prevalence rate (60.2%). Unilateral PDC was significantly associated with aplasia of upper lateral incisors, whereas bilateral PDC was associated with aplasia of third molars. PDC showed reciprocal significant associations with bilateral small-sized upper lateral incisors. None of the three hypotheses offered in support of the "guidance theory" in the etiology of PDC were corroborated by the findings of the present study. The occurrence of other dental anomalies concurrent with PDC, sex differences, and the bilateral expression of PDC, all confirm the genetic component in the etiology of this tooth disturbance.