Association between the inclination of the lateral incisors and the position of the erupting canines on panoramic radiographs.

OBJECTIVE. To analyze correlations between the inclination of the permanent maxillary lateral incisors and the intraosseous position of the erupting permanent maxillary canines on panoramic radiographs. MATERIAL AND METHODS. The inclination of the lateral incisor to the midline, the mesiodistal position of the crown of the canine, and the inclination of the canine to the midline and to the long axis of the adjacent incisor were measured on panoramic radiographs of 1013 subjects aged 8-11 years. RESULTS. The distal inclination of the lateral incisor crown increased until 10 years, after which no significant changes occurred. The canine erupted with increasing mesial inclination of the crown until 9 years, after which it began to progressively right itself. As a result, inclination of the canine to the adjacent incisor increased between 8 and 9 years and decreased between 10 and 11 years. Until the children reached 9 years of age, the more mesial the crown of the unerupted canine, the greater the decrease in the distal inclination of the lateral incisor crown. CONCLUSIONS. The inclination of the crown of the lateral incisor varies during eruption of the canine, increasing distally until 10 years as a physiological stage in the mixed dentition. The inclination of the lateral incisor is also associated with the mesiodistal position of the canine crown. The mesial intraosseous location of the canine crown results in righting of the lateral incisor.

Factors influencing the stability of miniscrews. A retrospective study on 300 miniscrews.

The aim of this study was to investigate, over a period of approximately 3 years, the reactions to orthodontic loading of a type V titanium miniscrew. In this retrospective study, conducted in a private practice, the records of 300 miniscrews inserted in 132 consecutive patients (80 females, 60.6 percent) by the same surgeon were evaluated. The mean age of the patients was 23.2 years. Three types of miniscrews (type A: diameter 1.5 mm, length 9 mm; type B: diameter 1.5 mm, length 11 mm; and type C: diameter 1.3 mm, length 11 mm) were used. The clinical variables evaluated included the loading time and location of the miniscrew in relation to the gingiva and root. The success rates with different variables were compared using chi-square or Fisher's exact test where appropriate. A cumulative survival rate of 81 percent (243/300) was found using Kaplan-Meier analysis, with an optimum success rate for the 1.3 mm wide miniscrew inserted in the attached gingiva, with immediate loading applied. Cox proportional hazard regression showed significant differences between success rate and the following parameters: gender, loading time, gingival or bone localization, and diameter of the miniscrews. Considering the clinically controllable parameters, and within the limits of this retrospective study, 1.3 mm diameter miniscrews inserted in attached gingiva and immediately loaded had the most favourable prognosis.