F.G. Ritto

Effects of surgical correction of class III malocclusion on the pharyngeal airway and its influence on sleep apnoea

The objective of this study was to evaluate, through cone beam computed tomography, the immediate changes in pharyngeal airway space (PAS) after orthognathic surgery in class III patients, and to determine the influence of surgery on the development of obstructive sleep apnoea hypopnoea syndrome (OSAHS). A prospective study was conducted; 33 patients were divided into three groups: mandibular setback surgery (nine patients), bimaxillary surgery (18 patients), and maxillary advancement surgery (six patients). PAS measurements obtained pre- and postoperatively were compared using the t-test. All patients were assessed clinically for OSAHS before surgery and at 6 months postoperative using the Berlin questionnaire and a combined clinical assessment, which included the assessment of OSAHS symptoms, Epworth Sleepiness Scale score, and body mass index. Patients undergoing isolated mandibular setback surgery demonstrated a decrease in total PAS volume, in hypopharynx volume, and in minimum cross-sectional area of the pharynx immediately after surgery (P<0.05). The clinical analysis did not reveal signs or symptoms of OSAHS in any of the 33 patients. Although patients who underwent mandibular setback surgery alone demonstrated a volume reduction in the PAS and a decrease in minimum cross-sectional area, these reductions were not accompanied by signs or symptoms of OSAHS.

Accuracy of maxillary positioning after standard and inverted orthognathic sequencing

OBJECTIVE This study aimed to compare the accuracy of maxillary positioning after bimaxillary orthognathic surgery, using 2 sequences. STUDY DESIGN A total of 80 cephalograms (40 preoperative and 40 postoperative) from 40 patients were analyzed. Group 1 included radiographs of patients submitted to conventional sequence, whereas group 2 patients were submitted to inverted sequence. The final position of the maxillary central incisor was obtained after vertical and horizontal measurements of the tracings, and it was compared with what had been planned. The null hypothesis, which stated that there would be no difference between the groups, was tested. RESULTS After applying the Welch t test for comparison of mean differences between maxillary desired and achieved position, considering a statistical significance of 5% and a 2-tailed test, the null hypothesis was not rejected (P > .05). Thus, there was no difference in the accuracy of maxillary positioning between groups. CONCLUSIONS Conventional and inverted sequencing proved to be reliable in positioning the maxilla after LeFort I osteotomy in bimaxillary orthognathic surgeries.

Sleep-disordered breathing following mandibular setback: a systematic review of the literature.

IntroductionA mandibular setback reduces space in the pharyngeal airway, and it has been suggested that it might induce sleep-disordered breathing.ObjectivesAn evidence-based literature review was conducted to identify the effect of mandibular setback on the respiratory function during sleep.MethodsThe authors performed a systematic review of pertinent literature published up to 2014. A structured search of literature was performed, with predefined criteria. A survey of the PubMed, ScienceDirect, and Cochrane database was performed. A manual search of oral and maxillofacial surgery-related journals was accomplished. Potentially relevant studies then had their full-text publication reviewed.ResultsA total of 1,780 publications were evaluated, through which nine papers (seven case series and two case–control studies) were selected for the final review. No evidence of sleep disorder after six months was related in 223 patients. In one study, two patients developed obstructive sleep apnea syndrome after surgery, and in another two studies, seven patients presented an increase of obstructive apneas/hypopneas events and oxygen desaturation index. Most of the patients analyzed were young and thin.ConclusionThere was no evidence of postoperative sleep apnea syndrome after a mandibular setback surgery. However, one should always consider a potential reduction of the upper airway space during the treatment plan. Obese patients and those submitted to large amounts of mandibular setbacks present a higher chance to develop obstructive sleep apnea syndrome.

Evaluation of postoperative complications after mandibular third molar surgery with the use of platelet-rich fibrin: a systematic review and meta-analysis

The current literature was reviewed to analyze the effects of platelet-rich fibrin (PRF) on postoperative complications after mandibular third molar surgery (pain, alveolar osteitis, swelling, and bone healing). A comprehensive literature search was performed up to 2016 in the PubMed/MEDLINE, Cochrane Library, LILACS, and ScienceDirect databases and the grey literature. Additional records were identified through manual and reference searches. The full-text articles of potentially relevant studies were reviewed; only randomized clinical trials were included. Two review authors assessed the risk of bias independently. A total of 1430 publications were evaluated, of which seven were selected for qualitative analysis and two for quantitative analysis. A meta-analysis was performed only for alveolar osteitis, due to the considerable heterogeneity among studies for the other outcome variables. There were 485 extractions (243 test, 242 control) in 280 patients. PRF appeared to accelerate healing in mandibular third molar surgery, reducing postoperative pain and swelling. Quantitative analysis showed a decrease in prevalence of alveolar osteitis (odds ratio 0.31, 95% confidence interval 0.13-0.77, Z=2.54, P=0.01). Although more clinical trials of a better design and with larger samples are necessary to allow definitive conclusions to be drawn, PRF is a potentially useful biomaterial.

Comparison of the accuracy of maxillary position between conventional model surgery and virtual surgical planning

The aim of this study was to determine whether virtual surgical planning (VSP) is an accurate method for positioning the maxilla when compared to conventional articulator model surgery (CMS), through the superimposition of computed tomography (CT) images. This retrospective study included the records of 30 adult patients submitted to bimaxillary orthognathic surgery. Two groups were created according to the treatment planning performed: CMS and VSP. The treatment planning protocol was the same for all patients. Pre- and postoperative CT images were superimposed and the linear distances between upper jaw reference points were measured. Measurements were then compared to the treatment planning, and the difference in accuracy between CMS and VSP was determined using the t-test for independent samples. The success criterion adopted was a mean linear difference of <2mm. The mean linear difference between planned and obtained movements for CMS was 1.27±1.05mm, and for VSP was 1.20±1.08mm. With CMS, 80% of overlapping reference points had a difference of <2mm, while for VSP this value was 83.6%. There was no statistically significant difference between the two techniques regarding accuracy (P>0.05).

Platelet-rich fibrin in oral surgical procedures: a systematic review and meta-analysis

The effect of platelet-rich fibrin (PRF) in enhancing the healing after oral surgical interventions is still a matter of debate. The purpose of this study was to identify instances where PRF has been shown to be effective in oral surgical procedures. A comprehensive literature search was performed up to 2017 on PubMed/MEDLINE, Cochrane Library, Web of Science, Scopus and LILACS databases and grey literature. The full-text of potentially relevant studies were reviewed and only randomized clinical trials (RCTs) were included. A total of 559 studies were found, of which 30 were included for qualitative analysis and 13 for quantitative analysis. Three review authors assessed the risk of bias independently. The available literature suggests that PRF has a positive effect in improving alveolar preservation on extraction sockets and around dental implants. The qualitative analysis showed a significantly better effect of PRF in promoting bone regeneration for alveolar cleft reconstruction. The meta-analysis for third molar surgery showed a decrease in prevalence of alveolar osteitis. PRF increased implant stability 1 week and 1 month after surgery (P=0.0005 and 0.0003). Due to the lack of studies with low risk of bias and a limited number of patients available, further RCTs are needed to confirm these results.