Facial growth direction after surgical intervention to relieve mouth breathing: a systematic review and meta-analysis.

OBJECTIVES: A systematic review was performed to assess the prognosis for facial growth direction documented by mandibular plane inclination and anterior face height in growing subjects who had undergone surgical intervention to relieve mouth breathing (PROSPERO database, registration no. CRD 42013005707). METHODS: PubMed, Scopus, Web of Science, the Cochrane Library and LILACS were searched based on the guidelines of the PRISMA statement. Included were longitudinal studies with mouth-breathing patients who had undergone surgical interventions to relieve their respiratory pattern, with a minimum follow-up of one year. RESULTS: A total of 1555 studies were identified, whereby only three nonrandomized clinical trials comprising 155 participants met the inclusion criteria. Primary outcome was change between the initial and final measurements of the mandibular plane-SN angle (95% confidence interval [CI] -2.13° [-3.08, -1.18]). Secondary outcomes included changes in total anterior face height (AFH; 95% CI -0.76 mm [-1.91, 0.38]), upper AFH (95% CI 0.09 mm [-0.57, 0.74]), and lower AFH (95% CI 0.06 mm [-0.87, 0.99]). Risk of bias was low for most of bias domains and the quality of evidence across the studies was considered to be very low. The design, the small number of participants, and the absence of blinding generated imprecision. CONCLUSIONS: There is very low evidence that the mandibular growth direction became more horizontal during the first year after surgery to treat mouth breathing. The total anterior facial height decreased, although not always significantly.

Severe root resorption resulting from orthodontic treatment: prevalence and risk factors.

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset.