Prediction of mandibular incisor and canine crowding changes in the mixed dentition

To test the hypothesis that preeruptive tooth positions and dental arch parameters might forecast crowding changes, a sample of 47 aboriginal children (26 males, 21 females) was selected stringently on the basis of Class 1 characteristics and an untreated dentition unaffected by caries or attrition. Crowding scores, radiographic relationships of 765E, and dental arch dimensions were evaluated for the mixed dentition (Stage 1, 8.91 +/- 1.05 years) and earliest emergence of the permanent dentition (Stage 2, 12.48 +/- 0.97 years). Changes between the stages were calculated and the sample was divided into two groups, according to an increase (Group 1) or decrease (Group 2) in incisor and canine crowding. Multivariate and multiple regression analyses were used to identify predictors (Stage 1 radiographic and dental arch parameters) of incisor and canine crowding behavior. Dental arch form and tooth size were important factors in measuring the amount of incisor or canine crowding at Stage 1 and Stage 2. Neither the radiographic nor the dental arch predictors proved useful in forecasting crowding changes. Group 2 dental arches tended to be initially narrower, shallower, and more crowded; however, they showed greater molar and canine width expansion and lessened arch depth reduction than Group 1 cases. Many cases showed a reduction in canine crowding from mixed to permanent dentition. This appeared to be largely independent of the observed incisor crowding. Sexual, racial, and individual variations in dentofacial pattern reinforce the need to carefully consider interceptive extraction or space-regaining therapy for each patient because of the unpredictability of crowding behavior during the transition from mixed to permanent dentition.     

Prediction of lower canine and premolar widths in the mixed dentition.

The purpose of this investigation was to determine whether, with multiple regression analysis, a more accurate method than is now available for predicting the widths of unerupted mandibular canines and premolars of mixed-dentition patients could be developed. Regression analyses were performed on data derived from 83 Caucasian subjects (42 males and 41 females) who participated in the Iowa Growth Study. Measurements were taken on plaster casts of the mandibular incisors, canines, premolars, and first molars. Measurements of the mandibular canines, premolars, and first molars were obtained from periapical radiographs taken with a long-cone technique. Newly developed regression equations for each sex had the highest correlation coefficients and smallest absolute errors of estimate when compared to previously published methods. The new equations and previous prediction methods were tested on a sample of 55 orthodontic patients (23 males and 32 females). The newly developed equations were also the most accurate method of prediction in the orthodontic patient sample.     

Prevalence of primary canine hypoplasia of the mandibular teeth.

The purpose of this study was to determine the prevalence of an uncommon lesion of the primary mandibular canines (primary canine hypoplasia), and its association with age, race, gender, dental caries, fluoridation status of the drinking water, breast-feeding, and geographic location. The study population comprised 2686 randomly selected children, black and white, 4 and 8 years old, who were enrolled in accredited private and public preschools and elementary schools in Mississippi. There were 1318 males and 1368 females, 1289 white children and 1397 black children, 1353 4-year-olds and 1333 8-year-olds. Results indicate that an association exists for race (P = 0.0001), gender (P = 0.01), and dental caries (P = 0.0001), but not for age (P = 0.07), geographic location (P = 0.73), fluoridation status of the water supply (P = 0.145), or breast-feeding (P = 0.392). The prevalence rate of primary canine hypoplasia was 33.2% for black children and 17.2% for white children. These data indicate that this lesion is significantly more prevalent in blacks than whites, and that teeth with this lesion have a greater probability of developing dental caries.     

Multiple supernumerary teeth in the maxillary canine and mandibular premolar regions: a case in the postpermanent dentition

BACKGROUND: A supernumerary tooth is an extra tooth above the normal number, of which approximately 90% occur in the premaxillary region and show rudimentary forms of crown morphology. Most cases occur singly, with bilateral occurrence in the maxillary canine regions very rare in children with no other associated diseases or syndromes. CASE REPORT: A case of a 14-year-old boy with bilateral supernumerary teeth with normal crown shapes in both the maxillary canine and mandibular premolar regions. The supernumerary teeth in the maxilla were diagnosed at 12.2 years of age and in the mandible at 14.1 years of age. CONCLUSION: Four supernumerary teeth in the maxillary and mandibular canine-premolar region is a rare finding.     

Effects of prolonged breast- and bottle-feeding on occlusal characteristics in the primary dentition

The purpose of this study was to assess the effects of prolonged breast- and bottle-feeding on the growing primary dentition. This longitudinal study was conducted through a survey questionnaire and clinical examination of 592 children from 18 months to 36 months of age. Selected occlusal characteristics were compared among groups of children with different durations of breast- or bottle-feeding. The prevalence of breast-feeding at 18 months, 24 months and 36 months of age was 9.3%, 3.2% and 0.2% respectively. Prevalence of bottle-feeding was 14.4%, 2.9% and 0.7% respectively. Deepbite showed tendencies towards increasing prevalence with increased bottle-feeding duration. One third of the children who continued bottle-feeding at 24 months of age exhibited deepbite. Anterior crossbite were significantly more prevalent among those with continued breast-feeding at 18 months but ceased by 24 months (28.0%) than for that in the habit-free group (11.7%). However, anterior crossbite showed tendencies towards decreasing prevalence with increased breast-feeding duration. The prevalence of anterior crossbite was 6.7% in the children who continued breast-feeding at 24 months of age. However, the study suggests that spontaneous change in the occlusion following feeding discontinuation, although longer-term longitudinal studies are needed to demonstrate such changes directly.     

Effects of oral habits' duration on dental characteristics in the primary dentition.

BACKGROUND: Studies dating to the 1870s have demonstrated that long-term nonnutritive sucking habits may lead to occlusal abnormalities, including open bite and posterior crossbite. However, little is known as to whether habits of shorter durations have lasting effects. METHODS: The authors collected longitudinal data on nonnutritive sucking among children through a series of questionnaires regularly completed by parents. Researchers examined the children at ages 4 to 5 years and obtained study models. The models were measured for dental arch parameters (including arch width, arch length and arch depth) and assessed for overjet, overbite and posterior crossbite. The authors compared the dental arch and occlusal conditions among groups of children with nonnutritive sucking habits of different durations. RESULTS: Children with nonnutritive sucking habits that continued to 48 months of age or beyond demonstrated many significant differences from children with habits of shorter durations: narrower maxillary arch widths, greater overjet and greater prevalence of open bite and posterior crossbite. In addition, compared with those who ceased their habit by 12 months of age, those with habits at 36 months of age had significantly greater mandibular canine arch widths, maxillary canine arch depths and overjet, while those with habits at 24 months and 36 months had significantly smaller palatal depths. Prevalence of anterior open bite, posterior crossbite and excessive overjet (> 4 millimeters) increased with duration of habits. CONCLUSIONS: While continuous nonnutritive sucking habits of 48 months or longer produced the greatest changes in dental arch and occlusal characteristics, children with shorter sucking durations also had detectable differences from those with minimal habit durations. CLINICAL IMPLICATIONS: It may be prudent to revisit suggestions that sucking habits continued to as late as 5 to 8 years of age are of little concern.     

Panoramic radiographic findings of the mandibular growth from deciduous dentition to early permanent dentition

The outlines of mandibular rami, condyles, coronoid process, and corpus in panoramic radiographs of normal children from deciduous to early permanent dentition were traced and digitized. Nine linear and four angular measurements were measured. During the observation period, the lengths for all the linear measurements increased, however, the angles for all the angular measurements decreased. The shape of condyle and gonion significantly correlated with the growth of ramus and corpus.     

Trauma to the primary dentition

The guiding principle in managing trauma to the primary dentition is potential sequelae to the permanent tooth. If the risk to the permanent tooth is great, the primary tooth should be removed. If esthetics are a concern to the parent, a number of appliances can be fabricated to temporarily manage this issue. It is important that parents realize that the desire to maintain optimum esthetics by maintaining a significantly injured primary tooth can, in many cases, cause more damage to the permanent tooth. Where avulsions have occurred, the old adage "when in doubt, leave it out" is still perhaps the most reliable advice.     

Indicators of mandibular dental crowding in the mixed dentition

PURPOSE: Dental crowding occurring in the anterior part of the mandible in the early mixed dentition has been a subject of increasing concern for child patients, their parents, and the pediatric dentist. The aim of this study was to evaluate indicators of crowding found at the primary dentition, which may lead to the future manifestation of crowding at the anterior part of the mandibular arch in the early mixed dentition. METHODS: Skeletal and dental morphological characteristics at the stage of primary dentition were compared between two groups, using dental casts and cephalograms of 23 subjects. These two groups had been formed by evaluating the degree of crowding at 9 years of age (12 normal and 11 crowded cases). RESULTS: The size of several teeth in the crowding group was significantly greater than that found in the normal group. For the cephalometric measurements, a statistically significant difference was found only in the cranial base dimension (S-SE). The stepwise discriminant analysis showed that the mesiodistal size of the maxillary primary canine, the maxillary and mandibular dental arch lengths, and the posterior cranial base length (S-Ba) were effective discriminators in separating the two groups. CONCLUSIONS: It is concluded that larger primary tooth size is the chief indicator in the development of dental crowding. However, the maxillary and mandibular dental arch lengths and the cranial base dimensions, especially that of the posterior cranial base length in the primary dentition, should also be considered as indicators when attempting to predict dental crowding in the early mixed dentition.     

Malocclusion in the primary dentition

In this paper we analyze the type and frequency of malocclusions in a group of 100 health children with complete primary dentition. Bjork's method for epidemiological registration was taken as a basis. Of the examined children, 78% had some malocclusion type. The most frequent was the increased horizontal overbite. In vertical overbite relation we find anterior open bite, increased overbite, anterior open bite, increased overbite.     

Orthodontic treatment of the primary dentition

Five patients were treated for corrections of problems in the primary dentition. Anterior and posterior crossbite, deep overbite malocclusion, and overbite malocclusion were treated with simple removable orthodontic appliances. Early orthodontic treatment for these patients helped resolve any functional problems that could interfere with later growth and development, such as health and function of the TMJ complex.     

Effects of removing inferior alveolar neurovascular structures on mandibular growth and the eruption of permanent dentition in puppies

Investigation was performed on the effects of removing the inferior alveolar neurovascular structures on the permanent dentition and mandibular growth. Five puppies with erupted deciduous teeth had the inferior alveolar neurovascular structures removed unilaterally. When the test animals were 28 weeks old, examination revealed that the deciduous teeth on the side operated had exfoliated but permanent teeth did not replace them. On the other hand, the permanent teeth on the side not operated on replaced the exfoliated deciduous teeth. After a second period of 28 weeks, the germs of the permanent teeth on the side operated on were still buried in the mandibular bone, and the permanent teeth on the side not operated on erupted normally. Mandibular measurements demonstrated that translative and transformative growth and developmental processes were normal in both the sides operated on and the sides not operated on.     

Orthodontic treatment of transposition of permanent mandibular lateral incisor and left canine in mixed dentition: a case report

The purpose of this study was to present the orthodontic treatment of a unilateral transposition of a permanent mandibular left canine and permanent mandibular lateral incisor during middle transitional dentition in a 10-year-old female. A panoramic radiograph showed the apex of the permanent mandibular left lateral incisor to be resting on the mesial corner of the permanent mandibular left canine crown, which was ectopically erupted in the proximity of the primary mandibular left second molar. A removable appliance was used to upright the permanent mandibular left lateral incisor, after which a utility arch was used until full eruption of the permanent dentition. Treatment continued with a fixed appliance system that included all teeth until the transposition of the canine and lateral incisor was corrected and a Class I occlusion with a favorable smile was obtained (at 36 months).     

两种缝合方式对下颌低位阻生智齿拔除术后并发症的影响

目的观察两种不同的缝合方式对下颌低位阻生智齿拔除术后并发症的影响。方法选择100例需翻瓣去骨拔除的下颌低位阻生智齿,随机分为观察组和对照组各50例。术中均采用传统角形切口(近中颊侧切口+远中切口),对照组拔牙术后切口采取完全缝合(远中切口缝合+颊侧切口缝合),观察组拔牙术后切口采取部分缝合(远中切口缝合+龈瓣转折处缝合,颊侧切口不缝合),两组术后均常规预防性抗感染治疗。比较两组术后48 h及7 d拔牙后出血、面颊部肿胀、疼痛及张口受限情况,并作统计学分析。结果两组术后在48 h及7 d拔牙后出血、疼痛、张口受限及面部肿胀程度均无显著性差异(P>0.05)。结论两种缝合方式对于下颌低位阻生智齿拔除术后出血、疼痛、张口受限及局部肿胀程度等并发症并无明显差异,但部分缝合术可以减少手术操作时间,简化手术过程,减少患者的创伤。     

Influence of the maxillary canine on mandibular fracture.

The length of the root of the mandibular canine tooth has been considered by many authors as being a source of weakness in the mandible. It has also been suggested that a direct blow or a bending force around this tooth can result in traumatic injury. We advance a theory that implicates the maxillary canine tooth as directly contributing to the mandibular canine region fracture pattern.