Asymmetric Changes in Shape of Anterior Teeth - Dental Esthetics

Introduction, Aim: The esthetic dentition is a substantial part contributing to the overall face esthetics. The shape of anterior teeth which are visible in a smile is an important aspect of the esthetic perception. The aim of the presented study was to determine the impact of the shape and size of particular anterior teeth on dental esthetics. Methods: A photograph of a young woman's mouth 9×13 cm (base) with an attractive smile and regular dentition was modified in the software Adobe Photoshop CS5. With this software different varieties of the same smile were produced, involving only a one-sided adjustment of shape and size of crowns of upper central and lateral incisors and upper canines. One shape was selected for central incisor, lateral incisor and canine. There were prepared 23 photographs with asymmetrical changes. The photographs were evaluated by three groups of evaluators: dentists, orthodontists and laymen. Each evaluator filled in a questionnaire in which expressed his/her perceived level of attractiveness for each photograph by marking a point in a linear scale between "0 = least" and "5 = most attractive". The distance from 0 to the mark was recorded and then expressed in per cents. Results: The average evaluation of the smile in all 25 photographs was 32% in case of dentists (SD 22), 42% in case of orthodontists (SD 27) and 50% in case of laymen (SD 28). The least esthetic shape evaluation was a square shape with a flat incisal edge of central incisors widened by 2 mm, by 1.5 mm and narrowed by 2 mm opposite to the initial. The most esthetic shape of central incisor is considered a harmonious shape with rounded angles. In case of lateral incisors the least esthetic shape was widened by 2 mm, narrowed by 2 mm. The most esthetic is shape of sharp mesial angle, rounded distal part, widened by 0.5 mm, by 1 mm and narrowed by 0.5 mm. Conclusion: All evaluators considered the harmonious shape with rounded angles and the shape of sharp mesial angle, rounded distal part in the lateral incisor as a most esthetic. The shape of lateral incisors widened by 0.5 mm or by 1 mm is considered esthetic. The shape widened by 2 mm was considered as an unaesthetic. When planning an orthodontic treatment it is necessary to consider the shape of teeth and their possible adjustment (recountouring, prosthetic adjustment with veneer/crown)

Anchorage in Orthodontic Treatment

The change in position and relationship of first permanent molars as well as the change in relationship and in axial position of upper and lower incisors in orthodontic therapy with extractions was measured.The sample comprised 55 patients; 28 patients were treated with extraction of two upper premolars, 27 patients were treated with extraction of four premolars - two in the maxilla and two in the mandible. The mesial movement of molars was present which was planned in many cases, however, in treatment without extractions in lower arch also the unplanned mesial movement of lower molars was found. In 8 of 28 patients without extraction in lower arch the lower incisors moved more than 2 mm in labial direction.The change in axial position of incisors was significant only in the sample of patients with extraction of four premolars. Interincisal angle increased by 11.18°, apex of the upper central incisor moved in labial direction by 1.02 mm (with regard to NB line). In the sample with extraction of two maxillary premolars there were no statistically significant changes in the axial position of incisors

OCCURENCE OF UNDIAGNOSED ORTHODONTIC ANOMALIES IN CHILDREN AT ELEMENTARY SCHOOLS IN OLOMOUC REGION

Introduction, aim: Within regular preventive dental check ups, dentists are obligated to asses in oral cavity not only hard and soft tissues, but also the intercuspidation and relation of dental arches. Reality, that some anomalies are indicated for early (interceptive) treatment, underlines importance of orthodontic assessment in children with mixed and young permanent dentition. The aim of this paper was to find out with noninvasive clinical assessement the occurence of children aged 6-13.9 years with orthodontic anomalies at elementary schools in Olomouc region, that so far were not in orthodontic dispensarization or treatment. Material and methods: Intraoral assessment of potential orthodontic anomalies was performed in 312 pupils of elementary schools in Olomouc region aged 6 to 13.9 years (134 boys and 178 girls). The pupils were divided into categories according sex and age (6-7.9 years, 8-9.9 years, 10-11.9 years and 12-13.9 years). The occlusion in maximal intercuspidation, Angle class, overjet and overbite were assessed in every child. If orthodontic anomaly was diagnosed and simultaneously this anomaly has not been in treatment yet, the child received request form for further examination in Orthodontic Department of Clinic of Dentistry in Olomouc. Results: Total 33 children had an undiagnosed or untreated orthodontic anomaly, that made 10.58% of all assessed children. The anomalies were more frequent in girls (11.24%) than in boys (9.70%). In younger age categories (6-7.9 years and 8-9.9 years) the frequency of those anomalies was approximately 6%, in older age categories (10-11.9 years a 12-13.9 years) the frequency was up to 15%. The most common diagnosed untreated anomaly was negative overjet, followed by increased overjet and lateral crossbite. Conclusions: The occurence of untreated orthodontic anomalies in observed children was relatively high. That can be explained with only three reasons: Either the child did not regularly visit his/her dentist, the doctor failed to diagnose anomaly within regular check up, or the parents were not interested in treatment after the doctor's recommendation

Resorption of Root Apex during Orthodontic Tooth Intrusion Using Light and Heavy Forces

Introduction, aim: The aim of this prospective study was to find a relationship between the external apical resorption and magnitude of orthodontic force during tooth intrusion. Relationship between the amount of intrusion and the extent of root resorption was investigated as well. Methods: The sample included 34 premolars in 17 patients. The light force (LF - 50 cN) and heavy intrusion force (HF - 150 cN) were applied on contra-lateral teeth. The measurements were performed at time before treatment (T0) and after six-month intrusion (T1). The measurements were registered also on the extracted premolars at the end of experiment. Two clinical parameters, four Cone Beam CT parameters and two parameters on extracted teeth were evaluated. The differences were statistically processed with two-sample t-test. Results: The extent of intrusion was significantly greater during heavy force activation; it was almost three times higher in comparison with light force (4.64 mm compared to 1.53 mm). The tooth was shortened at vestibular site in both groups (0.31 mm in LF and 0.67 mm in HF). However, the difference between both groups was not statistically significant (p = 0.06). The significantly shortened tooth was at palatal site in both groups (0.49 mm and 0.75 mm) and the difference was also not significant (p = 0.37). In comparison of root lengths, they were significantly shorter at vestibular site (0.49 mm and 0.75 mm), but the difference between groups was not significant (p = 0.18). Conclusion: Heavy forces lead to a more extensive intrusion in comparison with light forces. Significant root length shortening occurs after the intrusion with both 50 cN and 150 cN force. The relationship between the amount of intrusion force or the extent of intrusion and the apical root resorption was not confirmed