L.G.M. de Bont

Efficacy and co-morbidity of oral appliances in the treatment of obstructive sleep apnea-hypopnea: A systematic review

The Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a common sleep-related breathing disorder characterized by repetitive obstructions of the upper airway during sleep. Modification of pharyngeal patency by Oral Appliance (OA) therapy has been suggested as an alternative to various treatment modalities for OSAHS. To determine the evidence base with respect to the efficacy and co-morbidity of OA therapy in OSAHS, we conducted a systematic review of the available literature. Primary outcome measures were the reduction in number of upper-airway obstructions and co-morbidity related to the craniomandibular or craniofacial complex, respectively. Eligible studies regarding efficacy were independently assessed by two assessors using a quality assessment scale. Effect sizes of methodologically sound studies were calculated. In identical interventions, effect sizes were pooled with the use of a random-effects model. Given the scarcity of controlled studies related to co-morbidity, appraisal was confined to a description of eligible studies. Sixteen controlled trials related to efficacy were identified. With respect to the primary outcome measure, OA therapy was clearly more effective than control therapy (pooled effect size, -0.96; 95% confidence interval [CI], -1.49 to -0.42) and possibly more effective than uvulopalatopharyngoplasty. Although patients generally preferred OA therapy, improvement of respiratory variables, such as the number of upper-airway obstructions, was usually better in Continuous Positive Airway Pressure (CPAP) therapy (pooled effect size, 0.83; 95% CI, 0.59 to 1.06). Moreover, specific aspects related to OA design may influence patient-perceived efficacy and preference. Twelve patient-series and one controlled trial related to co-morbidity were identified. Analysis of the data suggests that OA therapy may have adverse effects on the craniomandibular and craniofacial complex. Although CPAP is apparently more effective and adverse effects of OA treatment have been described, it can be concluded that OA therapy is a viable treatment for, especially, mild to moderate OSAHS. Controlled studies addressing the specific indication and co-morbidity of OA therapy are warranted.

Obstructive Sleep apnea Therapy

In clinical practice, oral appliances are used primarily for obstructive sleep apnea patients who do not respond to continuous positive airway pressure (CPAP) therapy. We hypothesized that an oral appliance is not inferior to CPAP in treating obstructive sleep apnea effectively. We randomly assigned 103 individuals to oral-appliance or CPAP therapy. Polysomnography after 8–12 weeks indicated that treatment was effective for 39 of 51 persons using the oral appliance (76.5%) and for 43 of 52 persons using CPAP (82.7%). For the difference in effectiveness, a 95% two-sided confidence interval was calculated. Non-inferiority of oral-appliance therapy was considered to be established when the lower boundary of this interval exceeded −25%. The lower boundary of the confidence interval was −21.7%, indicating that oral-appliance therapy was not inferior to CPAP for effective treatment of obstructive sleep apnea. However, subgroup analysis revealed that oral-appliance therapy was less effective in individuals with severe disease (apnea-hypopnea index > 30). Since these people could be at particular cardiovascular risk, primary oral-appliance therapy appears to be supported only for those with non-severe apnea.

Smallest Detectable Difference in Outcome Variables Related to Painful Restriction of the Temporomandibular Joint

The smallest detectable difference is the smallest statistically significant change in measurement results. In the field of temporomandibular disorders, the smallest detectable difference is not a commonly used concept. Most outcome studies are based on comparisons of group means, although this does not provide information about individual changes or about the clinical relevance thereof. The smallest detectable difference for maximal mouth opening was calculated from previously published reliability coefficients and the standard deviations of different samples of healthy subjects and patients with complaints of the temporomandibular joint. The smallest detectable difference of pain intensity measured with different visual analogue scales was calculated from the reliability coefficients and standard deviations of a heterogeneous group of pain patients. The smallest detectable difference of function impairment was calculated for a group of patients with complaints of the temporomandibular joint. For maximal mouth opening in healthy subjects, the smallest detectable difference was 5 mm. Repeated measurements improved it to 3 mm. The smallest detectable difference on a visual analogue scale was 28 mm for actual pain intensity and 22 mm for minimal pain as well as for maximal pain intensity. For total function impairment of patients with complaints of the temporomandibular joint, the smallest detectable difference was 8 units on a 0 to 68 scale.

Short-term outcome of arthroscopic surgery of temporomandibular joint osteoarthrosis and internal derangement: A randomized controlled clinical trial

Various types of treatment have been proposed for patients with temporomandibular joint (TMJ) osteoarthrosis and internal derangement. We examined the suitability of several assessment instruments developed in previous investigations for treatment-evaluation in a clinical trial comparing arthroscopic surgery with non-surgical treatment for a specific subgroup of TMJ osteoarthrosis and internal derangement, characterized by joint pain and restricted mobility. Twenty-one patients appeared to obey strict criteria for participation, and were randomly assigned to receive arthroscopic surgery followed by post-operative physical therapy (n = 9), or non-surgical treatment (n = 12). Individual outcome was assessed immediately following treatment and after 6 months based on a priori defined criteria. Patients treated with arthroscopic surgery reported more pain relief and more improvement of mobility than patients treated non-surgically, although clinical assessment results were comparable between the two groups. No major changes were observed regarding general well-being and interference with daily activities. The results of this pilot study indicate that the assessment methods are sufficiently sensitive for changes in pain, mobility, and functional ability. Despite the higher degree of subjective pain relief and appreciation of improvement of mobility in the arthroscopic surgery group, with these more formal assessment instruments this difference could not be confirmed. It is concluded that the preliminary results should be verified in a larger trial with a slightly adjusted design.

Computed tomography in differential diagnosis of temporomandibular joint disorders

Computed tomography (CT) has great potential for imaging intra- and extracapsular hard-tissue abnormality of the temporomandibular joint (TMJ). CT is not the best method of imaging disk position and form. For differential diagnosis of TMJ disorders, CT is especially successful in bony lesions. The study includes 16 examples of TMJ hard-tissue abnormality. In the differential diagnosis of all cases, CT played a decisive role.

Predictors of Obstructive Sleep Apnea-Hypopnea Treatment Outcome

Oral appliance therapy is an alternative to continuous positive airway pressure (CPAP) for treating the obstructive sleep apnea-hypopnea syndrome. However, the ability to pre-select suitable candidates for either treatment is limited. The aim of this study was to assess the value of relevant variables that can predict the outcome of oral appliance and CPAP therapy. Fifty-one patients treated with oral appliance therapy and 52 patients treated with CPAP were included. Relevant clinical, polysomnographic, and cephalometric variables were determined at baseline. The predictive value of variables for treatment outcome was evaluated in univariate and multivariate analyses. The outcome of oral appliance therapy was favorable, especially in less obese patients with milder sleep apnea and with certain craniofacial characteristics (mandibular retrognathism in particular). Neither univariate nor multivariate analyses yielded variables that reliably predicted the outcome of CPAP. We conclude that the variables found in this study are valuable for pre-selecting suitable candidates for oral-appliance therapy.

Ultrasound stimulation of maxillofacial bone healing.

A substantial part of the maxillofacial surgery practice deals with maxillofacial bone healing. In the past decades, low-intensity ultrasound treatment has been shown to reduce the healing time of fresh fractures of the extremities up to 38%, and to heal delayed and non-unions up to 90% and 83%, respectively. Based on the assumption that the process of bone healing in the bones of the extremities and maxillofacial skeleton is essentially the same, the potential of ultrasound to stimulate maxillofacial bone healing was investigated. Although limited evidence is available to support the susceptibility of maxillofacial bone to the ultrasound signal, ultrasound may be of value in the treatment of delayed unions, in callus maturation after distraction, and in the treatment of osteoradionecrosis.

The Theoretical Optimal Center of Rotation for a Temporomandibular Joint Prosthesis: A Three-dimensional Kinematic Study

A unilateral temporomandibular joint (TMJ) prosthesis may cause dysfunction of the contralateral, natural TMJ because of lack of translatorial movements of the prosthetic side. The natural translatorial capacity of the mandible can be restored in part by a TMJ prosthesis with a fixed center of rotation (CR), positioned inferiorly to the center of the natural mandibular condyle. The aim of this study was to determine the optimal position for the fixed CR of a unilateral TMJ prosthesis. A mathematical model was used to analyze different positions of the CR. These positions were evaluated based on the calculated rotation of the mandible in the frontal (θf) and horizontal (θh) plane, and the mediolateral movement (MLM) of the contralateral natural condyle. For current TMJ prostheses, with the CR positioned in the center of the natural condyle, 6h exceeded the natural limits. When the CR was shifted inferiorly, all parameters improved, particularly θh. The addition of an anterior shift to an inferior shift slightly worsened θf, while the addition of a posterior shift to an inferior shift slightly improved θf and worsened MLM. We concluded that the functioning of the contralateral TMJ improves by shifting the CR inferiorly. An anterior shift may be added to remain within the contour of the mandibular ramus. The proposed position of the CR is 15 mm inferior to the center of the natural condyle, combined, if necessary, with an additional anterior shift of 5 mm.

Wear-testing of a temporomandibular joint prosthesis : UHMWPE and PTFE against a metal ball, in water and in serum

For a temporomandibular joint prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm3/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm3/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ prosthesis articulation is 0.47 (mm3/10(6) cycles), which is considered acceptable.

Complaints related to mandibular function impairment after closed treatment of fractures of the mandibular condyle

This study analysed the relationship between complaints and mandibular function after closed treatment of fractures of the mandibular condyle in a prospective study. In a 1-year follow-up, complaints were assessed during physical examination and function was assessed using the mandibular function impairment questionnaire (MFIQ), scoring range 0-68. Data from 114 patients (41 women, 73 men), mean age 28.1 years (SD 13.3), were available. On average the MFIQ scores were low 3.4 (SD 7.3). Ten patients (9%) experienced pain and 45 (39%) patients had a MFIQ score > 0. Mean mouth opening was 51.9 mm (SD 8.4). Occlusion was perceived as moderate or poor by 24% of the patients. In the logistic regression analysis mandibular function impairment (MFIQ score > 0) was entered as a dependent variable. Risk factors for mandibular function impairment were: pain, perceived occlusion (moderate or poor), absolute difference between left and right horizontal movements and age. A protective factor was mouth opening. The results of this study show that complaints (i.e. pain, perceived occlusion, reduced mouth opening, difference between left and right lateral movements and increased age) are predictors of mandibular function impairment after closed treatment of fractures of the mandibular condyle.