The combination of submerged primary molars and permanent teeth deletion is rare. This article reported a case of several submerged primary molars, permanent teeth deletion and a cone-shaped maxillary lateral incisor and discussed based on relevant literatures.
Dentition, Permanent ; Humans ; Incisor ; Molar ; Tooth, Deciduous

OBJECTIVETo compare and analyse the distribution and characteristic of born missing teeth.

METHODSA total of 183 simple hypodontia patients was reviewed and statistically analysed.

RESULTSThere was no significant difference in the number of missing teeth between different sexs (P > 0.05), and there was also no significant difference in the number of missing teeth among different sites (maxilla, mandible or left and right sides) (P > 0.05). The mandibular second premolar was the most frequently missing tooth. The missing molars were more commonly seen in oligodontia patients who had six missing teeth or beyond than hypodontia patients with less than six missing teeth (P < 0.05).

CONCLUSIONSEach hypodontia patient has his own clinical manifestation, and appropriate treatment should be planed accordingly for these patients.

The purpose of this study w-s to predict the respose to the chincap therapy from the initial cephalometric measurements and to obtain the indication of chincap therapy. 40 patients selected for this study were classified into two groups by the occlusal stability after completion of permanent dentition and the iiu4n ovement of facial profile, after chincap therapy. One was g response group which consisted of 25 children and the other was poor response group with 15 patients. Various measurements of the craniofacial structure in the initial lateral cephalogram were calculated and analyzed by t-test and discriminant analysis. The results were, as follows 1. Good response group had more horizontal growth pattern in initial stage of treatment, and the contributing measurements were Bjork sum, anterior-posterior facial height ratio, gonial angle, lower gonial angle and occlusal plane to AB plane angle. 2. The critical points and predictive values of the influential skeletal measurements were calculated. 3. The discriminant function was obtained from three. major influential measurements; Bjork sum, gonial angle and occliml plane to AB plane angle, and this function could discreminate correctly in 85% of this samples.
Child ; Dental Occlusion ; Dentition, Permanent ; Humans

Retrostpective study of two groups of patients was conducted to evaluate the physiologic drift of the mandibular teeth following the extraction of four first premolars. The concept of physiologic drift, commonly referred to as "driftodontics", following first premolar extractions has been gaining acceptance in the orthodontic community, the exact nature and amount of drift has not been adequately documented. There were also no guide lines as to when drift should be allowed to occur. The purpose of this study was to quantify physiologic drift of the untreated mandibular dentition following extraction of the four first premolars during the early permanent and late permanent dentition stages. The early permanent dentition extraction sample(Group 1) included 26 patients and the mean age at pretreatment was approximately 13.5 years. The observation period following extraction was approximately 6.96 months. The late permanent dentition extraction sample(Group 2) included 31 patients. The mean age at pretreatment was 21.3 years, followed by a observation period of 7.26 months. During the observation period, except for the extractions, no other mandibular therapy was rendered. Pre-and post-treatment lateral cephalograms and dental casts were analyzed. The obtained results were as follows 1. Group 2 showed marked changes in movements of the mandibular incisors and canines but minimal changes in molars. 2. The amount of changes in movements of the mandibular incisors and canines were significantly greater in Group 1 than in Group 2. The results showed no differences in rates of molar movements between groups. 3. Physiologic drift of the dentition produced desirable changes such as decreased Incisor Irregularity.
Bicuspid* ; Dentition* ; Dentition, Permanent ; Humans ; Incisor ; Molar ; Tooth

For the purpose of interpretation of positional changes of craniofacial structures in Class III malocclusion between mixed and permanent dentition, 73 normal samples and 103 Class III samples of mixed dentition and 125 normal samples and 168 Class III samples of permanent dentition were selected. Comparative cephalometric analysis was undertaken between them respectively by mesh diagram method to evaluate the positional changes of maxilla and mandible in anteroposterior direction and vertical direction and also the inclination changes of maxillary and mandibular incisors in labio-lingual direction. The following results were obtained: 1. The antero-posterior positional changes of the maxilla and mandible were posterior direction of maxilla and anterior direction of mandible. 2. The vertical positional changes of the maxilla and mandible were superior direction of both maxilla and mandible. 3. The labio-lingual inclination changes of the maxillary and mandibular incisors were lingual direction of both maxillary and mandibular incisors.
Dentition, Mixed ; Dentition, Permanent* ; Incisor ; Malocclusion* ; Mandible ; Maxilla

The author studied the dental arch widths and lengths height of palates at 2 groups of dentition : mixed dentition, early permanent dentition, young adult, having normal occlusion and dentition. The models of the 336 maxillary and mandibular casts, made from alginate-base hydrocolloid impressions were measured and analyzed statistically. The result as follows; 1. The upper intercanine width increased between the mixed dentition group and early permanent dentition group but there was no change in the young adult group in both sexes. Teh lower intercanine width increased between the mixed dentition group and early permanent dention group in the male. 2. The upper and lower 1st bimolar width increased slightly with age in the male but there was no change in the female. 3. The sex difference found in this study was one of absolute size, the female being slightly smaller than the male in the early permanent dentition group and young adult. 4. The arch length had no notable sexual differences and decreased between the mixed dentition group and early permanent dentition group. There was change in the arch length in the young adult. 5. The height of palate increased gradually with age.
Colloids ; Dental Arch* ; Dentition ; Dentition, Mixed ; Dentition, Permanent ; Female ; Humans ; Male ; Palate ; Sex Characteristics ; Young Adult*

Retained deciduous teeth are defined as the succedaneous permanent teeth have erupted while the primary teeth were retained, or the permanent teeth unerupted while the primary teeth remained in the permanent dentition. One case of multiple retained deciduous teeth was reported.
Dentition, Permanent ; Humans ; Male ; Tooth Eruption ; Tooth, Deciduous

OBJECTIVE: The purpose of this study was to evaluate the possibility of using a digital model and cone beam computed tomograph (CBCT) image for model analysis. METHODS: Model analyses of CBCT images, plaster models, and digital models of 20 orthodontic patients with a permanent dentition with no proximal metal restorations, were compared. RESULTS: The average differences of tooth size measurements were 0.01 to 0.20 mm, and the average difference of arch length discrepancy measurements were 0.41 mm in the maxilla and 0.82 mm in the mandible. The difference in Bolton discrepancy measurements was 0.17 mm for the anterior region and 0.44 mm overall but with no statistically significant difference. When comparing CBCT images with plaster models, the average differences in tooth size measurements were -0.22 to 0.01 mm, and the average differences in arch length discrepancy measurements were 0.43 mm in the maxilla and 0.32 mm in the mandible. Difference in Bolton discrepancy measurements were 0.35 mm in the anterior region and 1.25 mm overall. CBCT images showed significantly smaller overall Bolton discrepancy measurements. CONCLUSIONS: Although there were statistically significant differences in some model analysis measurements, the ranges of measurement errors of the digital model and CBCT images were clinically acceptable. Therefore, a digital model and CBCT image can be used for model analysis.
Cone-Beam Computed Tomography ; Dentition, Permanent ; Humans ; Mandible ; Maxilla ; Tooth

The purpose of this study was to investigate the changes of the position of the mental foramen according to age by using panorama of children with mixed and early permanent dentition. 180 panorama of 6 to 13-year-old boys and girls were analyzed and PiView(Infinitt, Korea) program was used.The horizontal position of the mental foramen was evaluated by the relative position of the teeth. The vertical position of the mental foramen was evaluated by the ratios between the distance from the center of the mental foramen to the inferior border of the mandible and the distance from to the alveolar crest to the inferior border of the mandible.The mental foramen was horizontally located in the anterior aspect of the second primary molar(premolar), and vertically slight below the half of mandibular body. As the age increased, it moved to the posterior and the downward and showed a significant correlation with age.
Adolescent ; Child ; Dentition, Permanent ; Female ; Humans ; Mandible ; Tooth

Anterior crossbite is a common malocclusion in the early deciduous dentition. Even today, many these malocclusion patients are not treated until the mixed or permanent dentition. And the purpose here is to emphasize the need for early diagnosis and possible treatment for these anterior crossbite malocclusions and their associated facial patterns. Case histories of 4 patients selected from the author's practice are presented. Different methods of treatment are evaluated. Some improvement was achieved in all patients from an early interceptive regimen, although ultimately corrective orthodontic treatment may still be needed in some. It is concluded that early interception of deciduous anterior crossbite malocclusion should by attempted in patients; there should be no delemma in reaching such a decision. And it is essential for diagnosis and treatment to determine exact variations in growth when some appliance are used, it is recommended that growth-related records be made as early as possible.
Dentition, Permanent ; Diagnosis ; Early Diagnosis ; Humans ; Malocclusion* ; Tooth, Deciduous*