Antinociceptive effect of the cannabinoid agonist, WIN 55,212-2, in the orofacial and temporomandibular formalin tests

Orofacial pain disorders are frequent in the general population and their pharmacological treatment is not always adequately resolved. Cannabinoids have demonstrated their analgesic effect in several pain conditions, both in animal models and in clinical situations. The aim of the present study was to evaluate the cannabinoid-mediated antinociception in two inflammatory models of orofacial pain (orofacial and temporomandibular joint (TMJ) formalin test) and to compare it with a spinal inflammatory model (paw formalin test). WIN 55,212-2 (0.5, 1mg/kg), a synthetic cannabinoid agonist, was intraperitoneally (i.p.) administered prior to formalin and significantly reduced the nociceptive behavioural responses in these inflammatory tests. To elucidate which subtype of receptor could be involved in such effect, two selective cannabinoid antagonists were administered prior to WIN. SR141716A (1mg/kg i.p.), the CB1 receptor-selective antagonist, was able to prevent the cannabinoid-induced analgesia in all three models, whereas SR144528 (1mg/kg i.p.), the CB2 receptor-selective antagonist, only prevented it in the paw formalin test. A comparison with the antinociceptive effects of morphine (2.5, 5, 10mg/kg, i.p.), indomethacin (2.5, 5mg/kg, i.p.) and ketamine (25, 50mg/kg, i.p.) was also performed. Morphine displayed a dose-dependent reduction of acute and inflammatory pain in all three models, whereas indomethacin and ketamine only attenuated inflammatory pain at the highest tested doses. These results indicate that the cannabinoid-induced antinociception in the orofacial region is mediated by activation of CB1 cannabinoid receptor. Moreover WIN was as effective as morphine and more effective than indomethacin and ketamine, in oral inflammatory pain.

[Primary and secondary prevention procedures of temporo-mandibular joint disease in the evolutive age]

In the last years prevention of temporomandiboular joint (TMJ) disease had acquired great importance. According to the neuro-occlusal rehabilitation (RNO) it is possible to say that TMJ disease starts since first years of life. So it is important both for dentist and for pediatric know what are the conditions and the atypical functions which predispose to this pathology. The aim of this work was to show how it is possible to intercept since primary teeth and the correct norms of primary and secondary prevention.

Preventive orthodontics for the 5- to 7-year-old with the Nite-Guide technique

This preventive orthodontic technique is applicable for the 5- to 7-year-old to prevent problems involving crowding, spacing, rotations, overbite, overjet, gummy smiles, Class II molar relations, and TMJ dysfunction from developing. The technique is based on accepted published research on the development of the dentition. Patients are typically started at 5 or 6 years of age and wear two preformed appliances only while sleeping. The active stage lasts about 2 years. The same appliance is used as a retainer until 12 years when the patient is dismissed About 75% to 80% do not require further orthodontics. The total procedure takes about 2 to 3 hours of total chair time.

Risk factors for the occurrence and prevention of temporomandibular joint and muscle disorders: lessons from 2 recent studies

INTRODUCTION

Our objectives were to demonstrate how standard epidemiologic measurements can assist in evaluating the risk factors for tempormandibular joint and muscle disorders (TMJMD) and to determine whether prevention is feasible.

METHODS

We reviewed 2 recent studies that examined third-molar extractions and severe mandibular retrognathia as risk factors for TMJMD. Cumulative incidences were available from these studies. By using these values, standard epidemiologic measurements of risk, including population attributable risk (PAR), attributable risk (AR), population attributable risk percent (PAR%), and attributable risk percent (AR%), were calculated. (PAR and AR are reported as the numbers of cases per 10,000 per year.)

RESULTS

In the third-molar extraction study, PAR, AR, PAR%, and AR% were 5, 10, 25%, and 40%; in the severe mandibular retrognathia study, they were 0.5, 17.5, 10%, and 80%, respectively.

CONCLUSIONS

This review supports the current consensus that most risk factors explain only a small portion of TMJMD in the population. However, some factors might explain a significant portion of TMJMD in persons exposed to particular risk factors. This review supports the current consensus that prevention, by screening the population for risk factors and intervening, is probably not justified. Modification of certain risk factors among exposed persons to prevent TMJMD might be warranted. Incidence data and epidemiologic measurements of risk are needed to evaluate the importance of risk factors for the occurrence and prevention of TMJMD, in both the population and exposed persons.

Effect of estrogen on bone resorption and inflammation in the temporomandibular joint cellular elements

Several epidemiological studies have reported that temporomandibular disorder is more prevalent in women, which suggests the involvement of sex hormones, such as estrogen, in the pathogenesis of this disease. PCR amplification and Western blotting were employed to target the expression of estrogen receptors (ERs) in human fibroblast-like synovial and ATDC5 cells. The effect of estrogen was investigated through the expression of RANKL, osteoprotegerin (OPG), M-CSF/CSF-1 and c-fms. We showed expression of M-CSF/ CSF-1 and c-fms, with time-dependent increase in both after the addition of estrogen. Based on previous studies reporting that M-CSF/CSF-1 regulates the proliferation and differentiation of hemopoietic progenitor cells into mature macrophages, we put forward a new hypothesis based on the increased inflammation and tendency of females to suffer more from temporomandibular disorder (TMD) in the presence of external exacerbating factors. Detection of RANKL and OPG in ATDC5 and expression of both in HFLS was confirmed with complete disappearance of the RANKL band, and marked increase in the expression of OPG after 1 h from the addition of estrogen.

An integrated fuzzy logic and web-based framework for active protocol support

OBJECTIVE

To develop a general purpose web-based system for active support in using protocols.

METHODS

The conceptual model underlying the design of the overall decision support system is drawn from fuzzy set theory and fuzzy logic giving rise to a framework for both acquiring and representing descriptive and operational protocol knowledge. It has been conceived as a web application, designed and implemented according to the technological standards of Internet, in particular XML language and web services, to guarantee distributed functionalities for multicentric studies and the re-use of domain knowledge and problem solving strategies.

RESULTS

Solutions have been evaluated experimentally addressing the specific domain of Temporomandibular disorders (TMD) specializing the general purpose procedures to the dedicated "Research Diagnostic Criteria" (RDC)/TMD protocol. The accuracy of the system was correlated with a set of 50 clinically cases consecutively selected from the Gnatology Department. The results were consistent in 100% of cases. The systematic observation by physicians of both activated rules and diagnostic judgements identified and explicitly formalized additional diagnostic rules in the same context.

CONCLUSIONS

Active protocol support based on fuzzy diagnostic reasoning and advanced web-based technologies shows great potentialities for the renewed role DSSs are called to play in the increasingly wide scale context of evidence-based medicine.

Amelioration of pain and histopathologic joint abnormalities in the Col1-IL-1beta(XAT) mouse model of arthritis by intraarticular induction of mu-opioid receptor into the temporomandibular joint

OBJECTIVE

To evaluate opioid receptor function as a basis for novel antinociceptive therapy in arthritis.

METHODS

We induced human mu-opioid receptor (HuMOR) expression in arthritic joints of mice, using the feline immunodeficiency virus (FIV) vector, which is capable of stably transducing dividing, growth-arrested, and terminally differentiated cells. Male and female Col1-IL-1beta(XAT)-transgenic mice developed on a C57BL/6J background and wild-type littermates were studied.

RESULTS

A single injection of FIV(HuMOR) into the temporomandibular joints of Col1-IL-1beta(XAT)-transgenic mice 1 week prior to induction of arthritis prevented the development of orofacial pain and joint dysfunction, and reduced the degree of histopathologic abnormality in the joint. In addition, FIV(HuMOR) prevented the attendant sensitization of trigeminal sensory neurons and activation of astroglia in brainstem trigeminal sensory nuclei. These effects were mediated by the transduction of primary sensory neurons via transport of FIV vectors from peripheral nerve endings to sensory ganglia, as evidenced by HuMOR expression in neuronal cell bodies located in the trigeminal ganglia, as well as in their proximal and distal nerve branches located in the main sensory and subnucleus caudalis of the brainstem and joints, respectively. The presence of MOR ligands predominantly in the descending trigeminal nucleus suggested that the observed antinociception occurred at the subnucleus caudalis. Articular chondrocytes and meniscal tissue were also infected by FIV(HuMOR), which presumably exerted an antiinflammatory effect on cartilage.

CONCLUSION

Our results indicate that prophylactic therapy with MOR overexpression in joints can successfully prevent the development of pain, dysfunction, and histopathologic abnormalities in the joints in arthritis. These findings may provide a basis for the future development of spatiotemporally controlled antinociceptive and antiinflammatory therapy for arthritis.

Dental compression syndrome and TMD: examining the relationship

Fifty years ago, McCollum and Stuart described a subtle pathology of function in the human masticatory system that was difficult to understand. That subtle pathology is the damage that results from compression of teeth. It is subtle because often the patient is unaware. It is pathologic because it applies untoward stress to the dentition, alveolar bone, and the TMJ. It is difficult to understand for many reasons: multiple etiology, few patient complaints, poor understanding of the deformations caused by DCS, the role of equilibration during treatment is unclear, and the dissimilar ways it takes its toll. For proper management of DCS, the general dentist should monitor for signs of compression and wear, educate the patient about the problem, and provide treatment. While every patient with a flattened dentition should not have their teeth dramatically altered or reconstructed, the dental profession should form a consensus that the natural, sharp morphology of teeth is superior to a flattened dentition, and should be preserved throughout one's lifetime.

[Dentofacial orthopedics and craniomandibular dysfunction]

There has been a recent recrudescence of cranio-mandibular disorders (CMD), predominantly affecting women. Even children can be affected by CMD, often under diagnoses by their families and by medical professionals. Therefore, a multidisciplinary approach is important when evaluating the variety of diagnostic and etiological problems. The search for postural etiology, whether lingual or dental, is always necessary to better act on the etiology of these disorders. The involvement of orthodontics, in the prevention of CMD, has three impacts: functional, aesthetic and psychological, allowing for a better balance of the cranio-mandibular system. This makes the treatment of cranio-facial orthopedics, a successful choice in the recovery of CMD.

Effect of a nociceptive trigeminal inhibitory splint on electromyographic activity in jaw closing muscles during sleep

The nociceptive trigeminal inhibitory (NTI) splint has been claimed to decrease the electromyographic (EMG) activity of jaw-closing muscles and relieve symptoms of various types of temporomandibular disorders (TMD) and bruxism. The present study was designed to address the question about EMG-changes during sleep. Ten patients (age: 23-39 years) with a self-report of tooth-grinding during sleep were recruited. Patients were examined at baseline and after each treatment period with the use of the Research Diagnostic Criteria for TMD. A portable EMG-device was used to record EMG-activity from the masseter muscle during sleep. The patients received two 2-week splint treatments in a randomized cross-over fashion; an NTI splint and a standard flat occlusal splint (OS). EMG data were analysed according to published criteria. Using a 10% of maximum clenching EMG-activity cut-off threshold to determine the number of EMG-events h(-1) of sleep, the NTI splint was associated with a significant reduction (9.2 +/- 3.2 events h(-1)) compared with baseline EMG (19.3 +/- 4.0; anova: P = 0.004, Tukey post hoc: P = 0.006), whereas there were no differences between the OS (16.2 +/- 4.7) and baseline EMG (19.2 +/- 4.1; P = 0.716). There were no effects of either NTI or OS on clinical outcome measures (anovas: P > 0.194). This short-term study indicated a strong inhibitory effect on EMG-activity in jaw closing muscles during sleep of the NTI, but not the OS. However, the EMG-activity was not directly related to clinical outcome. Further studies will be needed to determine long-term effects and possible side effects of the NTI splint.

[Radiation-induced temporomandibular joint damage in nasopharyngeal carcinoma patients after intensity-modulated radiotherapy]

BACKGROUND & OBJECTIVE

Radiation-induced temporomandibular joint damage is a kind of common complication after radiotherapy for nasopharyngeal carcinoma (NPC) patients. Trimus is the main symptom of this damage, and severely affects the quality of life of the patients. This study was to evaluate radiation-induced temporomandibular joint damage in NPC patients treated with intensity-modulated radiotherapy (IMRT), and analyze its affecting factors.

METHODS

From Feb. 2001 to Feb. 2003, 148 naive NPC patients were treated with IMRT by 2.27-2.80 Gy per fraction at a total dose of 63-77 Gy within 31-86 days. The distance between 2 dens incisivus medialis (DDIM) was measured before radiotherapy, and 6 months, 1 year, 2 years, and 3 years after radiotherapy, respectively.

RESULTS

The overall 1-, 2-, and 3-year survival rates were 97.26%, 94.83%, and 92.04%. The irradiation dose to temporomandibular joint was 17.9-51.36 Gy. Seven (4.73%) patients suffered from grade I-II temporomandibular joint damage after IMRT; no patient had grade III-IV temporomandibular joint damage.

CONCLUSIONS

IMRT can spare the temporomandibular joint from high dose irradiation. The risk of radiation-induced severe temporomandibular joint damage in NPC patients after IMRT is low.

Insufficient endogenous control of tumor necrosis factor-alpha contributes to temporomandibular joint pain and tissue destruction in rheumatoid arthritis

OBJECTIVE

To investigate whether pain and tissue destruction in the temporomandibular joint (TMJ) of patients with rheumatoid arthritis (RA) are influenced by plasma levels of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) or the soluble receptor TNFsRII.

METHODS

Fifty-one patients with RA were included. TMJ resting pain intensity, pain intensity upon mandibular movement, tenderness to palpation, pressure-pain threshold, and presence of anterior open bite were assessed. Venous blood was obtained for analysis of TNF-alpha, TNFsRII, and inflammatory markers.

RESULTS

A total of 29 patients had TMJ pain and 22 patients had anterior open bite. In the group of patients with TMJ pain, 12 had anterior open bite and 17 did not. In the patients without TMJ pain 10 patients had anterior open bite and 12 did not. Patients with or without anterior open bite did not differ regarding any investigated variable. Plasma TNF-alpha and TNFsRII were positively correlated in the total patient sample. TNFsRII was negatively correlated with degree of anterior open bite in patients with TMJ pain but positively correlated with TMJ pressure-pain threshold in patients with elevated plasma TNF-alpha.

CONCLUSION

Our results indicate that insufficient systemic endogenous control of TNF-alpha seems to contribute to TMJ pain and tissue destruction in RA.

[Some possibilities to assess maxillary-mandibular occlusion in fixed dental prosthesis]

Occlusion determination, registration and transfer represent an important phase of the fix prosthetic treatment. This goal can be achieved using different materials such as: silicon, special occlusal wax, ZOE paste, acrylic resin and occlusal rims. Specific techniques for specific clinical situations are described, together with some associated procedures: provisional restoration after tooth preparation and split wearing.

[Cranial asymmetries and their dento-facial and occlusal effects]

Cases of occlusal asymmetry detected in the temporary dentition are frequently associated with skeletal asymmetries of the cranial base. They should be corrected as soon as possible. Symmetry of these dental groups is achieved with the use of mini-screws implanted in designated sectors of the hard palate. When a new occlusal plane derived from the corrected maxilla is obtained, the mandible will re-center itself in relation to it. As a result cranial bones can remodel and the possibility of induced temporo-mandibular disorders is greatly reduced.

Alloplastic reconstruction of the temporomandibular joint in treatment of craniofacial developmental or congenital anomalies: a surgical case report

OBJECTIVE

To describe the surgical planning and treatment approach in addressing the oral and maxillofacial needs for one particular patient suffering congenital anomalies of the craniofacial anatomy. A secondary objective is to restore mandibular and maxillary function and esthetics to the young, adult patient. The tertiary objective is to educate the surgeon as to alloplastic implant options that may be available to restore function and relieve pain for the patient missing certain anatomical structures from birth.

METHODS

Through the use of advanced medical imaging tools, a thorough understanding of the patient's prior failed medical treatments, and a meticulous understanding of the benefits of alloplastic reconstruction, the surgeon can mitigate patient symptoms and at the same time increase the probability of a successful outcome. The surgeon can then collaborate with the surgical and implant design team to not only prescribe the surgical correction necessary, but also design and construct the actual temporomandibular joint (TMJ) and mandibular implants used for the case, as well as perform mock surgery on a stereolithography anatomical (SLA) model needed to restore function and esthetics for the patient. The end result is that a Patient-Specific (custom) (TMJ Implants, Inc., Golden, CO, USA) prosthesis can then be manufactured and adapted surgically to the patient's unique anatomy.

RESULTS

The early results from this alloplastic reconstructive surgery have brought forth the anticipated results of replacement of the congenitally absent TMJ, improvement of jaw function, reduction of joint pain, as well as improvement of the esthetics. Without this breakthrough surgical development, many of these congenital anatomically deficient patients would not be able to enjoy normal breathing, mastication, jaw function, esthetics, oral and dental health, and the emotional relief that these corrections allow.

CONCLUSIONS

Many patients who suffer birth-related anatomical deficiencies (such as cleft lip and branchial arch syndrome) never receive the surgical correction necessary. Many have had autogenous reconstruction of missing mandibular and TMJ structures only to relapse, at times, into a more disfiguring and lasting condition. By simply placing a Christensen Fossa-Eminence Prosthesis (FEP) and Condylar Prosthesis (CP) in a total joint-replacement solution, one is more likely to achieve satisfactory TMJ mobility and reduction in pain, as well as the mechanical replacement of missing anatomical structures and predictable and lasting improvement. As an additional benefit, the patient also would enjoy enhanced esthetics.

Potential role of disc repositioning in preventing postsurgical recurrence of traumatogenic temporomandibular joint ankylosis: a retrospective review of 17 consecutive cases

The potential role of disc repositioning in preventing postsurgical recurrence of traumatogenic temporomandibular joint (TMJ) ankylosis was investigated. Seventeen cases of traumatogenic TMJ ankylosis underwent disc repositioning during arthroplasty. During surgery, the dislocated disc was carefully dissected outside the ankylotic TMJ and repositioned over the top of the condylar stump, and then sutured to the soft tissue of the zygomatic root. In the 22 ankylotic TMJs of the 17 patients, dislocated discs were found in front of the ankylotic TMJ, behind the ankylotic TMJ or between the ramus and fossa. At the last follow-up (longer than 1 year) examination, interincisal opening distances ranged from 24 to 43 mm (mean 32.86 mm). No recurrence and TMJ symptoms were found during the period of follow-up. Disc repositioning in the treatment of traumatogenic TMJ ankylosis proves to be a feasible and effective method of preventing recurrence of this condition.

Effects of prosthetic treatment for shortened dental arches on oral health-related quality of life, self-reports of pain and jaw disability: results from the pilot-phase of a randomized multicentre trial

A multi-centre randomized clinical trial is under way at 14 university dental schools in Germany to compare prosthodontic treatments for the shortened dental arch (SDA). One of the aims of this pilot-study was to measure the effect of two treatment options of the SDA on oral health-related quality of life and on the Research Diagnostic Criteria (RDC) for temporomandibular disorders (TMD). Thirty-four patients participated in the pilot-study. Inclusion criteria were: all molars were missing and the presence of at least both canines and one premolar in each quadrant. Participants were randomly assigned to receive either removable partial dentures including molar replacement (RPD_group) or retain a premolar occlusion (PROC_group). The Oral Health Impact Profile (OHIP-49) and the RDC for TMD were completed by participants before treatment (pre-treatment), 6 weeks (6 wks), 6 months (6m) and 12 months (12 m) after treatment. At the 12-month follow up, data of 10 women and 11 men (mean age: 62 +/- 10 years) were available. Medians of the OHIP total-scores were as follows: RPD (n = 10), 43.5 (pre-treatment), 18.2 (6 wks), 13.3 (6m), 14.7 (12 m). PROC (n = 11): 31.8 (pre-treatment), 27.1 (6 wks), 8.8 (6m), 8.3 (12 m). Significant differences were shown for RPD_group between pre-treatment and 6m/12 m and for PROC_group between pre-treatment and 6m. There were no significant differences between treatment groups at any time. Within each group, an improvement of life-quality was observed. No significant difference could be reported between the two therapy concepts. This may be due to the low sample size within the pilot study.

A role for cyclooxygenase II inhibitors in modulating temporomandibular joint inflammation from a meal pattern analysis perspective

PURPOSE

Developing a valid noninvasive animal model to study temporomandibular joint (TMJ) inflammation/pain has proved difficult. However, its has been recently demonstrated that meal pattern analysis, and in particular meal duration, can be used as a biologic marker for TMJ inflammation/pain induced by bilateral injections of complete Freund's adjuvant (CFA). The present study was undertaken to confirm previous findings and extend them by using rofecoxib (VIOXX; Merck and Co, West Point, PA), a selective cyclooxygenase-2 inhibitor (COX-2-I).

MATERIALS AND METHODS

Forty-eight male rats were assigned to 1 of 4 groups: group 1, no CFA and no COX-2-I treatment; group 2, no CFA and treatment with the COX-2-I; group 3, bilateral TMJ CFA injection and no COX-2-I treatment; and group 4, CFA injection and treatment with the COX-2-I. Food intake was recorded by computer 24 hours before and for 48 hours after CFA injection. TMJ swelling, chromodacryorrhea, and meal patterns were quantified.

RESULTS

CFA increased swelling (P <.05), chromodaccryorrhea (P <.05), meal duration at 24 and 48 hours, and TMJ retrodiscal tissue interleukin-1beta (P < 0.01) in group 3, but treatment with the COX-2-I attenuated these effects in group 4, (CFA + COX-2-I).

CONCLUSIONS

These data confirm that meal pattern analysis, and in particular meal duration, is a noninvasive measure of TMJ inflammation/pain. However, this experiment has extended this model as a marker of drug treatment efficacy, specifically the efficacy of COX-2-I in treatment of orofacial inflammation/pain.

The effect of an interocclusal appliance on bite force and masseter electromyography in asymptomatic subjects and patients with temporomandibular pain and dysfunction

The aims of this study were to assess the effect of clenching with or without the presence of an interocclusal appliance (IOA) on bite force (BF) and masseter electromyography (EMG) in patients with temporomandibular pain dysfunction disorders (TMPD) and to compare these results with an asymptomatic age- and gender-matched control group. Ten patients with TMPD (mean age 26.9 years) were compared with eight healthy controls (mean age 25.3 years). Bilateral masseter EMG activity was recorded at rest, while clenching on the BF meter, while clenching on an IOA and while clenching on an IOA together with the BF meter. Significant left to right EMG activity asymmetry was found in the patient group at rest and during multiple clenching tasks in the control group. The patient group had significantly greater EMG activity at rest than controls. For all other tasks, the control group EMG activity was greater than the patient group. Use of an IOA significantly decreased EMG activity in both patient and control groups. BF was significantly greater in the control group on the right side for the different clenching tasks. Insertion of the IOA significantly increased BF in the control group. The results of this study indicate differences in EMG activity and BF during different clenching tasks and between patients with TMPD and asymptomatic subjects.

Complementary and alternative therapy use by patients with myofascial temporomandibular disorders

AIMS

To examine the prevalence and predictors of complementary and alternative medicine (CAM) use among patients with temporomandibular disorders (TMD), prior to their first treatment with an intraoral splint.

METHODS

Sixty-three women with a diagnosis of myofascial TMD, and who had never been prescribed an intraoral appliance, reported on their use of CAM and other treatments for their facial pain. In addition to providing a comprehensive symptom history, participants completed a 2-week daily diary in which they described the nature of daily efforts to reduce their facial pain.

RESULTS

Although more than half of all participants had not sought any prior treatment for their facial pain, 22.2% had received CAM treatment. The only single type of treatment more commonly used than CAM treatment was medication (28.6%). The most common type of CAM treatment was relaxation therapy (12.7%), followed by chiropractic treatment (9.5%). Although pain duration, pain severity, or mood did not predict CAM use, users were significantly more likely to report work or social disability associated with their facial pain and were more likely to report onset associated with an accident. CAM users were more likely than non-users to employ multiple pain reduction strategies over the 2-week daily diary report, including prescription medication use.

CONCLUSION

A sizeable minority of women with myofascial TMD report CAM treatment for their pain, even prior to an initial treatment with an intraoral splint. Since empirical reports have not adequately demonstrated their safety or efficacy, there is a need for controlled clinical trials evaluating the utility of CAM treatments for TMD.

Occlusal adjustment for treating and preventing temporomandibular joint disorders

To assess the effectiveness of occlusal adjustment (OA) for treating temporomandibular disorders (TMD) in adults and preventing TMD. The Cochrane Controlled Trials Register, MEDLINE and EMBASE were comprehensively searched using the Cochrane methods. Reports and review articles were retrieved. Unpublished reports or abstracts were considered from the SIGLE database. All randomized or quasi-randomized controlled trials comparing OA with placebo, reassurance or no treatment in adults with TMD. The outcomes were global measures of symptoms, pain, headache and limitation of movement. Data collection and analysis followed the Cochrane Oral Health Group's statistical guidelines. Results showed no difference between OA and control group in symptom-based outcomes for treatment or incidence of symptoms for prevention. There is no evidence that OA treats or prevents TMD. OA cannot be recommended for the management or prevention of TMD. Future trials should use standardized diagnostic criteria and outcome measures when evaluating TMD.

Proximal segment positioning in bilateral sagittal split osteotomy: intraoperative dynamic positioning and monitoring by sonography

PURPOSE

Most methods of condylar positioning merely maintain the preoperative condyle-fossa relationship and therefore produce similar prevalences of postoperative dysfunction. This study evaluates dynamic proximal segment positioning by intraoperative sonography versus the splint and plate technique discussed in a previous issue.

PATIENTS AND METHODS

Condylar positioning was monitored by sonography alone in 30 bimaxillary operated patients (14 Angle Class II, 16 Class III), the control group had a splint and plate positioning in 23 patients (9 Angle Class II, 14 Class III). The clinical dysfunction index, prevalence of condylar translation, and disc dislocation were compared preoperatively and at 1, 6, and 12 months postoperatively.

RESULTS

The postoperative range of motion did not disclose statistically significant differences between study and control group (Pearson's proportionality index r = 0.78, 2-way analysis of variance: P <.4, F = 4.4, alpha =.05 significance level). Sonographic placement allowed dynamic intraoperative monitoring of the condylar position and required an average of 5 minutes compared with 25 minutes for conventional positioning. Postoperative dysfunction prevalence was reduced 89% for Class II and 100% in Class III in the study group versus 50% for Class II and 100% for Class III in the control group (r = 0.45, P <.3, F = 9.3). Prevalence of disc dislocation was reduced 76% in Class II and 80% in Class III patients in the study group and 50% of Class II and 100% of Class III in the control group (r = 0.7, P <.48, F = 9.2).

CONCLUSIONS

Comparable postoperative reduction of condylar translation and recovery, dysfunction, and disc dislocation was seen with use of both methods in a 1-year follow-up. The new technique allowed intraoperative real-time monitoring and dynamic correction and was safe, easier, and faster than conventional plate positioning.