Periodontal healing after 'orthodontic extraction' of mandibular third molars: a retrospective cohort study.

In this study we investigated periodontal healing of mandibular second molars following 'orthodontic extraction' of adjacent impacted third molars, under the null hypothesis that there would be no difference in probing pocket depths (PPD) and clinical attachment levels (CAL) at the distal aspect of second molars before and after treatment. A retrospective survey was conducted of 64 patients who consecutively underwent 'orthodontic extraction' of mandibular third molars in close anatomical relationship with the mandibular canal from January 1997 to January 2011. Age, smoking habit, and PPD and CAL at the distal aspect of second molars before and after treatment were recorded. A statistically significant difference was found in PPD and CAL before and after treatment for the overall sample and for the sample classified by age (>25 or ≤25 years), smoking habit (smoker or non-smoker), and type of third molar impaction (horizontal, mesioangular, or vertical). Median PPD and CAL reductions amounted to 6mm and 5mm, respectively. The null hypothesis was rejected and orthodontic extraction proved to be indicated for those impacted mandibular third molars at high risk of a postoperative periodontal defect at the distal aspect of the adjacent second molar.

Reliability of different methods for measuring the inclination of the maxillary canines on panoramic radiographs.

OBJECTIVES: To test the reliability of 4 different methods of measuring maxillary canine inclination (CI) on panoramic radiographs, and to determine whether examiner experience level influenced these measurements under ideal experimental conditions. SETTING AND SAMPLE POPULATION: The sample consisted of 20 high-quality panoramic radiographs obtained under standardized conditions using the same radiological apparatus. MATERIAL AND METHODS: Canine inclination (CI) was measured as either the angle formed by the canine long axis and the midline (method A), a line passing through the suborbitary points (method B), the most superior points of condyles (method C) or the mesiobuccal cusp tip of the first molars (method D). Measurements were made at initial observation (T1) and after 3 months (T2) by 5 experienced orthodontists and 5 undergraduate dental students. RESULTS: Mean T1-T2 differences for the measurements were close to zero, with no relationship between their magnitude or direction for each method. Intra-rater reliability was excellent, with the lowest values being observed for method B and the highest for method C. No influence of the examiner experience level was detected. CONCLUSION: The four methods used in this study to measure CI showed excellent intra-rater and inter-rater reliability, irrespective of examiner experience level. Method B was the least reliable and method C the most reliable, if compared with the others.