[Oral appliances for obstructive sleep apnoea: What can we expect?] / Orthèses d'avancée mandibulaire et syndrome d'apnées-hypopnées obstructives du sommeil : qu'en attendre ? Revue de la littérature, comparaison par design.

INTRODUCTION: Mandibular appliances are a treatment option for obstructive sleep apnea. There are many designs, but in the literature they tend to be grouped into a single entity without considering that efficiency, tolerance, compliance, or side effects are inherent in the design of each of them. A more detailed literature review is therefore warranted for the reader who wants to understand the relative effectiveness of each appliance. STATE OF KNOWLEDGE: We conducted a literature search using the "oral appliance" and "obstructive sleep apnea" criteria on Pubmed, Embase and Cochrane. This allowed us to compare outcome parameters by appliance class and to highlight the rare studies comparing different appliances. CONCLUSIONS: Mandibular appliances are not a homogeneous entity. Common use includes only appliances designed for propulsion (with rods and jacks) and retention. However, the few comparative studies available do not identify which are the most effective types or the types with an optimal efficacy/tolerance ratio. PERSPECTIVES: Further appliance comparison studies are needed to determine the most effective type or with an optimal efficacy/tolerance ratio.

[Marginal bone loss around tissue level implants in the posterior part of the mandible].

OBJECTIVE: To clarify the related factors of marginal bone loss (MBL) around tissue level implants in the posterior part of the mandible. METHODS: A total of 116 tissue level implants were implanted in the mandibular posterior region of 76 patients. Patients' information, including general characteristics, implant characteristics, implant site characteristics, and prosthesis characteristics, was recorded. Their cone beam computed tomography data were measured immediately after implant placement, 3 months later, and 3 and 12 months after prosthesis loading. The measurement of MBL was conducted by One Volume Viewer software. SPSS 20.0 was used for statistic analysis. RESULTS: Smoking, cortical bone thickness (CBT), collum angle (CA), and implant local sanitation showed significant differences with body mass loss (P<0.05). No significant differences were found among sex, age, length of implant, diameter of implants, implant systems, bone height, prosthesis type, and MBL (P>0.05). CONCLUSION: The risk factors that caused MBL were smoking, thicker CBT, larger CA, and poor implant local sanitation. Among them, poor implant local sanitation had the highest correlation with MBL.

[Maxillomandibular advancement surgery as an optional therapy for patiens with severe obstructive sleep apnoea]. / Bimaxillaire osteotomie als mogelijke behandeling voor ernstig obstructieve slaapapneu.

Obstructive sleep apnoea (OSA) is a common chronic disorder which often requires lifelong treatment. Its prevalence in the Netherlands is estimated to be around 300.000 people. In this study 12 patients with severe OSA were treated with maxillomandibular advancement surgery between 2011 and 2012. The mean advancement during surgery was 8.7 mm and the mean postoperative admission was 4 days. All patients underwent polysomnography at 3 months. Three months after surgical treatment, the apnoea-hypopnea index had decreased with 74.9% (57.3 to 14.4). The subjective sleepiness of the patients had also decreased with a mean of 57.5%. The literature indicates comparable results in patients with severe OSAS, specifically a reduction of the apnoea-hypopnea index of 80-90%. Considering the successful results following maxillomandibular advancement surgery, this therapy is an appropriate alternative for patients who cannot cope with 'continuous positive airway pressure' or patients who want a permanent therapeutic solution. Further research is recommended to achieve higher levels ofevidence for maxillomandibular advancement surgery in patients with OSA.

[Oral appliances or maxillomandibular advancement osteotomy for severe obstructive sleep apnoea in patients refusing CPAP]. / Orthèse d'avancée mandibulaire ou ostéotomie maxillo-mandibulaire pour le traitement des syndromes d'apnées obstructives du sommeil sévères refusant la PPC.

OBJECTIVES: The management of patients with severe obstructive sleep apnea syndrome (OSAS) refusing or not tolerating continuous positive pressure ventilation (CPAP) remains problematic. We evaluated the effectiveness of oral appliances and of maxillomandibular advancement osteotomy. METHODS: One hundred and two patients with severe OSAS were included between 2001 and 2006. Maxillo-mandibular advancement osteotomy was proposed to patients less than 60 years of age, non obese and without comorbidities. The other patients were treated with oral appliances. All patients underwent polysomnography at 3 months. RESULTS: Group A: 25 patients with mean apnea-hypopnea index (AHI) at 45/h were treated by maxillo-mandibular advancement. Three months after the surgery, AHI had decreased from 45 to 7. The success rate was 89% when AHI was less than 15/h and 74% when AHI was less than 10/h. Sixteen patients performed a polysomnography one year after surgery with similar results. There were no major postoperative complications. Group B: 77 patients with a mean AHI at 41/h were treated with oral appliances. Only 23 patients underwent polysomnography at 3 months. The mean AHI had decreased from 41/h to 22/h. The success rate was 56% when AHI was less than 15/h and 30% when AHI was less than 10/h. DISCUSSION: We are confronted with an increasing number of severe OSAS patients with CPAP failure or intolerance. Surgery for maxillo-mandibular advancement is an effective alternative. However, it is not always indicated or accepted by the patient. So an oral appliance remains a useful therapeutic option despite its moderate success rate.

Biomechanical testing of different osteosynthesis systems for segmental resection of the mandible.

PURPOSE: This investigation assessed the mechanical behavior of 3 different locking and nonlocking reconstruction systems-Unilock 2.4, Reconstruction 2.4, and Reconstruction 2.7-with regard to plate and screw fracture. MATERIALS AND METHODS: Five different plate/screw configurations (Unilock 2.4-locking screws, Unilock 2.4 -conventional screws, Reconstruction 2.4-conventional screws, Reconstruction 2.7-conventional screws, and Unilock 2.4-locking screws with a 1-mm gap; Synthes, Umkirch, Germany) were tested on synthetic mandibles. All mandibles were resected on the left side between the canine and third molar, reconstructed, and loaded cyclically between 30 and 300 N up to 250,000 cycles or until screw or plate failure occurred. RESULTS: No screw fractures were observed. All plates fractured close to the distal fragment. The Unilock plates fixed with locking screws withstood significantly more cycles until failure than the Reconstruction plates 2.4 fixed with conventional MF-Cortex screws. No significant differences were found in the other groups. Only 2 of the 34 plates tested, both of the Reconstruction 2.7 system, reached the runout limit. CONCLUSIONS: Unilock plates fixed with locking screws have a higher long-term stability than the Reconstruction 2.4 system. A 1-mm gap between the plate and mandible does not lead to early screw failure in the Unilock 2.4 system with locking screws. The Reconstruction 2.7 system seems superior if well contoured, because 2 of those plates reached the runout limit; however, this system is not as easy to handle as the 2.4 systems, and good contouring is difficult to achieve. Therefore, we consider the Unilock 2.4 system with locking screws the best choice.

Association between marginal bone loss around osseointegrated mandibular implants and smoking habits: a 10-year follow-up study.

While many factors are conceivable, occlusal loading and plaque-induced inflammation are frequently stated as the most important ones negatively affecting the prognosis of oral implants. Currently, little is known about the relative importance of such factors. The aim of this study was to analyze the influence of smoking and other possibly relevant factors on bone loss around mandibular implants. The participants were 45 edentulous patients, 21 smokers and 24 non-smokers, who were followed for 10-year period after treatment with a fixed implant-supported prosthesis in the mandible. The peri-implant bone level was measured on intraoral radiographs, information about smoking habits was based on a careful interview, and oral hygiene was evaluated from clinical registration of plaque accumulation. Besides standard statistical methods, multiple linear regression models were constructed for estimation of the relative influence of some factors on peri-implant bone loss. The long-term results of the implant treatment were good, and only three implants (1%) were lost. The mean marginal bone loss around the mandibular implants was very small, about 1 mm for the entire 10-year period. It was greater in smokers than in non-smokers and correlated to the amount of cigarette consumption. Smokers with poor oral hygiene showed greater marginal bone loss around the mandibular implants than those with good oral hygiene. Oral hygiene did not significantly affect bone loss in non-smokers. Multivariate analyses showed that smoking was the most important factor among those analyzed for association with peri-implant bone loss. The separate models for smokers and non-smokers revealed that oral hygiene had a greater impact on peri-implant bone loss among smokers than among non-smokers. This study showed that smoking was the most important factor affecting the rate of peri-implant bone loss, and that oral hygiene also had an influence, especially in smokers, while other factors, e.g., those associated with occlusal loading, were of minor importance. These results indicate that smoking habits should be included in analyses of implant survival and peri-implant bone loss.

A within-subject comparison of mandibular long-bar and hybrid implant-supported prostheses: psychometric evaluation and patient preference.

Although it has been shown that patients are more satisfied with prostheses supported by implants than with conventional dentures, there have been few direct comparisons of the various designs of implant-supported prostheses. This within-subject crossover clinical trial was designed to compare two forms of removable prostheses which are frequently prescribed for the edentulous mandible: a long-bar overdenture supported by 4 implants and a two-implant hybrid overdenture. Sixteen completely edentulous subjects were given a new maxillary conventional denture: Ten of them received the mandibular long-bar prosthesis first and six the hybrid. After a two-month adaptation period, psychometric measures of various aspects of the prostheses and physiological tests of masticatory efficiency were carried out over three weeks. The mandibular prostheses were then changed and the procedures repeated. At the end of the study, subjects were asked to choose the mandibular prosthesis that they wished to keep, and final psychometric measures were taken. In this paper, the results of the psychometric assessment and patient preference are presented. Subjects assessed factors such as general satisfaction, quality of life, stability, retention, comfort, esthetics, ease of cleaning, speaking, and chewing, and how well-chewed foods were before being swallowed. Most of the factors except ease of cleaning and speaking were rated significantly better with long-bar overdentures than with hybrid ones. These results are consistent with the fact that all subjects chose long-bar overdentures, reporting stability, ease of chewing, and comfort as the most important factors influencing their choice. These results suggest that, although subjects assign high ratings for most factors to hybrid overdentures, they find long-bar overdentures to be significantly more stable, comfortable, and easier for chewing.

Analysis of reconstruction of mandibular defects using single stainless steel A-O reconstruction plates.

PURPOSE: This report reviews the results and complications of immediate reconstruction using a single stainless steel A-O plate after resection of mandibles invaded by malignant tumors. PATIENTS AND METHODS: Thirty-four patients were retrospectively evaluated. According to the extent of the tumor, hemimandibulectomy or segmental resection were performed in 4 and 30 cases, respectively. Five of 34 cases required a myocutaneous flap to close soft tissue defects. RESULTS: Nine of the 34 patients died during the follow-up period. Complications occurred in 7 of these patients: plate exposure was caused by local tumor recurrence (4 cases), screw loosening (1 case), and temporomandibular joint pain (2 cases). Twenty-five of the 34 patients (73.5%) were alive, with a mean follow-up of 47.4 months (range 6 to 115 months). Eighteen of the 25 surviving patients with the single A-O plate reconstruction did not show any complications. Thirteen of these (52%) patients had not undergone secondary reconstruction. Five of the 25 patients received secondary reconstruction for cosmetic or masticatory function reasons. Postoperative complications occurred in 7 of the 25 surviving patients (28%): extraoral plate exposure (2 cases), fracture of the plate (1 case), mandibular fracture (1 case), screw loosening (3 cases), and screw fracture (1 case). CONCLUSIONS: On the basis of the findings, it was concluded that a single A-O reconstruction plate can be used for temporary, or sometimes even permanent, reconstruction after mandibular resection.

Experience with AO reconstruction plates after partial mandibular resection involving its continuity.

A report is presented on experience with the use of 54 plates, without primary bone grafts, after resections for malignant tumours involving the continuity of the mandible, in 52 patients. There were complications in 27 cases: postoperative infection or soft tissue dehiscence occurred 20 times, chronic soft tissue perforation once, screw loosening twice, and plate fracture four times. Adjuvant radiotherapy and/or chemotherapy had no effect on the incidence of the complications. Seventeen of the plates (a good 30%) had to be removed prematurely due to the complications. Major deformity did not always occur if relative stabilization had developed through cicatrix formation. Thirty-seven plates (barely 70%) remained: in 19 cases until the death of the patient, in 3 cases until recurrence, in 12 cases until bone grafting, and in 3 cases they were still in situ up to 65 months. In principle, reconstruction plates have proven themselves. However, application and soft tissue coverage need great care and a great deal of experience.