Incidência de recessão gengival e mudança da inclinação dos incisivos inferiores após tratamento ortodôntico: um estudo coorte retrospectivo

Abstract

The position of the lower incisors has received much attention in the orthodontic literature and represents an important point in the treatment decision. Systematic reviews on this topic showed a low level of evidence for the association between incisor inclination and gingival recession, suggesting the need for further clinical studies to investigate the relationship between these variables. OBJECTIVES: verify the incidence of gingival recession and the mandibular incisors inclination change after orthodontic treatment. METHODOLOGY: The study design was a retrospective cohort study. From a total of 689 patients treated with fixed appliance, between the years 2004 and 2011 in the course of specialization in orthodontics FO-UFMG, 30 were included in the study due to exclusion criteria like incomplete forms, periodontitis or use of piercing. The subjects underwent clinical examination in 2013 to assess the presence or absence of gingival recession and radiographic evaluation to determine the inclination of the mandibular incisor. For the inclination of the lower incisor analysis three cephalometric parameters were considered before, immediately after orthodontic treatment and a period between 2 and 7 years after orthodontic treatment. The data of gender, age, oral hygiene habits, use of tobacco and alcohol consumption, gingival biotype, visible plaque index, periodontal clinical parameters and height of keratinized gingiva width were taken during the clinical examination. It was realized descriptive analysis of the sample. Friedman test was performed for dependent samples and Wilcoxon test with Bonferroni correction (p=0.017) were used to compare the cephalometric parameters, the three assessment times. RESULTS: the age average of the sample was 14.4 years (SD = 3.04) at the beginning of orthodontic treatment, 16.43 years (SD = 3.15) at the end of treatment and 21.87 years (SD = 3.43) at the time of the survey. The majority of the sample consisted of females 73.3%, with good oral hygiene habits (visible plaque index average of 26.8%), none of them were smokers and 20% consumed alcohol. The majority of patients showed a lower central incisor inclination relative to the mandibular plane (IMPA) greater than 95o, before treatment (70%), after the end of treatment (66.7%) and showed 2 to 7 years after the removal of the device (70%) The changes in the lower central incisor inclination (p=0.220) and mandibular arch length (p=0.054) over time were not statistically significant. The thick gingival biotype was present in 63% and no individual keratinized gingival showed less than 2mm width. Throughout the study period, 2 patients (6.7%) developed lingual gingival recession and 1 (3.3%) buccal, and recessions were 1mm and these individuals had completed treatment for 07 years. One of the subjects had two teeth with gingival recession. CONCLUSION: The incidence of gingival recession in mandibular incisors in a period between 2-7 years after the end of orthodontic treatment in subjects with a average age of 21.87 years, which comprised the sample, was 10%. In about 70% of the sample orthodontic correction did not change the inclination of the lower incisors, while maintaining a inclination greater than 95 º.