Dorrit W. Nitzan

Temporomandibular joint arthrocentesis: a simplified treatment for severe, limited mouth opening.

Seventeen patients complaining of suddenly occurring, severe, and persistent limited mouth opening were treated by irrigation of the upper compartment of the affected temporomandibular joint with lactated Ringers solution. This simple treatment was found to be highly effective in reestablishing normal opening and relieving pain for a follow-up period of 4 to 14 months.

Intraarticular pressure in the functioning human temporomandibular joint and its alteration by uniform elevation of the occlusal plane

Intraarticular pressure (IAP) was measured at the posterior slope of the eminence in the upper compartment of the temporomandibular joint (TMJ) of 35 individuals (28 females and 7 males) under local anesthesia. Pressure measurements were obtained with the jaw in rest position, during maximal mouth opening (MMO), and while clenching. During MMO, IAP decreased to levels ranging between -130 and -5 mm Hg (mean, -53.82 +/- 34.40 mm Hg), whereas during clenching the pressure was always positive (range, +8 to +200 mm Hg; mean, 63.90 +/- 52.25 mm Hg). The significance of the fluctuating pressures with respect to the joints maintenance and performance, as well as the potentially harmful effect of the positive pressure, especially when it is high and prolonged, are discussed. Females generated significantly higher pressures than males (73.70 +/- 61.06 mm Hg vs 31.42 +/- 11.47 mm Hg, P = .017). This gender difference regarding IAP may help elucidate the enigma of the considerably higher proportion of women with TMJ problems. In 22 of the patients IAP also was measured while clenching on a specifically constructed interocclusal appliance (IOA), which uniformly elevated the occlusal plane so as to reduce the force directed toward the TMJ. During clenching without the IOA, pressures ranged from 20 to 200 mm Hg (mean, 68.8 +/- 49.1), decreasing by 81.2% to IAP levels ranging from 0 to 40 mm Hg (mean, 7.9 +/- 10.9; P < .001) with the appliance in place. The use of an IOA as a palliative treatment for symptomatic TMJs is discussed.

Long-term outcome of arthrocentesis for sudden-onset, persistent, severe closed lock of the temporomandibular joint

PURPOSE This study analyzed the long-term effect of arthrocentesis for severe closed lock of the temporomandibular joint (TMJ) and reevaluated the pathogenesis of this condition based on the data obtained. PATIENTS AND METHODS Thirty-nine patients (40 joints) who had experienced sudden-onset, persistent limited mouth opening were the subjects of this study. After unsuccessful noninvasive treatment, arthrocentesis of the upper compartment of the affected TMJ was performed using saline. The follow-up, which consisted of patient self-assessment and clinical examination, ranged from 6 to 37 months (mean, 16.6 +/- 12.0 months). Visual analog scales were used for preoperative and postoperative self-evaluation of pain and dysfunction on forced mouth opening and for assessment of overall change in these parameters postarthrocentesis. Maximal mouth opening (MMO), contralateral movement (CLM) and protrusive movement of the jaw, and presence of joint noises were noted preoperatively and at clinical follow-up examinations. RESULTS At 6 to 37 months postarthrocentesis, MMO and CLM had increased significantly (from a mean of 23.10 +/- 5.15 mm to 44.25 +/- 4.96 mm, and from a mean of 4.81 +/- 2.36 mm to 8.20 +/- 1.90 mm, respectively; P < .001). Functional improvement was associated with a significant reduction in pain and dysfunction levels (from a mean of 9.24 +/- 2.90 to 1.45 +/- 1.74, and from a mean of 9.26 +/- 2.82 to 2.68 +/- 2.80, respectively, on a scale of 0 to 15; P < .001). The overall improvement, as expressed in pain and dysfunction levels, was about 95%, with no recurrence of severe closed lock. CONCLUSIONS Arthrocentesis for sudden-onset closed lock provided sustained normal joint function and marked pain relief. Because the available literature shows that arthrocentesis changes neither disc position nor disc shape, it places in doubt the concept of a displaced and deformed disc limiting joint function. Rather, the efficacy of lavage in resolving closed lock suggests that the condition is the result of sudden adherence of the normally shaped disc to the fossa, rendering it incapable of sliding. The characteristic features of sudden-onset, limited mouth opening warrants classification of this disorder as an independent entity within the realm of TMJ disturbances.

The Clinical Characteristics of Condylar Hyperplasia: Experience With 61 Patients

PURPOSE Much reported variation and discord exist regarding mandibular condylar hyperplasia (CH). This study evaluated some of the characteristics of this disorder in a series of 61 patients with active CH. PATIENTS AND METHODS A total of 61 patients with active temporomandibular CH who had been evaluated in our departments were included. Demographic, clinical, radiologic, and bone scintiscan data were collected and analyzed. Asymmetries were classified as transverse, vertical, or combined. RESULTS CH was diagnosed during the growth period in 22 patients, and 39 patients were older than 20 years (range, 11 to 80 years). In 66% of the patients, the main complaint was progressive facial asymmetry; and in the remainder, the main complaint was pain, dysfunction, or both. Transverse asymmetry predominated (52%), and vertical or combined asymmetry occurred in 31% and 16% of patients, respectively; asymmetry type was independent of age. The occlusal plane deviated in 48% of the patients. Laterality was significantly gender-biased (females, 72% right; males, 64% left; P = .017). The condylar head shape was normal in 15% of patients, deformed in 27%, and enlarged in 58%; the condylar neck was elongated in 69% and enlarged in 19%. All of these changes were uncorrelated with the type of asymmetry (vertical, transverse, or combined). CONCLUSIONS CH may occur at any age and is more prevalent in females. Clinicians should be aware that only some patients complain primarily of facial asymmetry, and that symptoms of temporomandibular disease also may be present. Because there is no correlation between the radiologic findings and the clinical evaluation, classification should be simplified and based on clinical manifestation only--in other words, the direction of asymmetry.

An alternative explanation for the genesis of closed-lock symptoms in the internal derangement process

Clinical and surgical data on 194 operated joints (135 patients) were used to substantiate a new concept challenging the presumed natural history of temporomandibular internal derangement (ID). A number of findings were incompatible with the traditional depiction of a progressive process based on gradual changes in disc position and shape. These findings were a lack or correlation between increasing age and the stages of the process; the percentage of patients in the third stage (closed lock) with limited opening (less than 25 mm) too severe to be caused solely by a nonreducible, displaced disc; the unexpectedly high incidence (greater than 50%) of normally shaped discs in the third stage of the process. A specific condition of severe and stubborn limited maximal mouth opening caused by total cessation of gliding, liable to occur at any age and unrelated to disc shape or position, which responds successfully to simple treatment by lavage and lysis, pressured injection, or arthrocentesis, was discerned. Lack of gliding was attributed to adherence of the disc to the fossa by a reversible effect such as a vacuum and/or decreased volume of synovial fluid of high viscosity. This condition was deemed worthy of an independent identity, dissociated from disc displacement, as a causative factor in the second and third stages of ID, and particularly as an aid to accurate diagnosis and treatment.

Liposomes act as effective biolubricants for friction reduction in human synovial joints.

Phospholipids (PL) form the matrix of biological membranes and of the lipoprotein envelope monolayer, and are responsible for many of the unique physicochemical, biochemical, and biological properties of these supermolecular bioassemblies. It was suggested that phospholipids present in the synovial fluid (SF) and on the surface of articular cartilage have major involvement in the low friction of cartilage, which is essential for proper mobility of synovial joints. In pathologies, such as impaired biolubrication (leading to common joint disorders such as osteoarthritis), the level of phospholipids in the SF is reduced. Using a human-sourced cartilage-on-cartilage setup, we studied to what extent and how phospholipids act as highly effective cartilage biolubricants. We found that large multilamellar vesicles (MLV), >800 nm in diameter, composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or of a mixture of DMPC and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) are superior lubricants in comparison to MLV composed of other phosphatidylcholines. Introducing cholesterol into liposomes resulted in less effective lubricants. DMPC-MLV was also superior to small unilamellar vesicles (SUV), <100 nm in diameter, composed of DMPC. MLV are superior to SUV due to MLV retention at and near (<200 microm below) the cartilage surface, while SUV penetrate deeper into the cartilage (450-730 microm). Superiority of specific PL compositions is explained by the thermotropic behavior (including compressibility) of the lipid bilayer. Correlating physicochemical properties of the MLV with the friction results suggests that MLV having lipid bilayers in the liquid-disordered phase and having a solid-ordered to liquid-disordered phase transition temperature slightly below physiological temperature are optimal for lubrication. High phospholipid headgroup hydration, high compressibility, and softness are the common denominators of all efficient PL compositions. The high efficiency of DMPC-MLV and DMPC/DPPC-MLV as cartilage lubricants combined with their resistance to degradation at 37 degrees C supports further evaluation of these MLV for treatment of joint impairments related to poor lubrication. This work also demonstrates the relevance of basic physicochemical properties of phospholipids to their activities in biological systems.

On the genesis of “dry socket”

One major school of thought regarding the pathogenesis of a dry socket occurring following tooth extraction is based on the concept that a blood clot fails to form, a concept that is, however, refuted by the clinical symptoms associated with the phenomena of a dry socket. A second theory maintains that, initially, clot formation takes place, but that the clot is subsequently lysed, bringing about the severe symptoms of a dry socket. Fibrinolysis generated by tissue activators only partly explains the occurrence of a dry socket. Based on the data accumulated in the literature, it is postulated that bacterial agents are involved in the fibrinolysis and that Treponema denticola may play a leading part in this process.

H2O2 renders cells accessible to lysis by exogenous phospholipase A2: a novel mechanism for cell damage in inflammatory processes

Phospholipase A2 (PLA2) and H2O2, secreted from activated inflammatory cells, play a central role in the tissue damage occurring in inflammatory processes. However, while exogenous PLA2 alone does not cause cell lysis, it readily does so when acting with H2O2. We have found that H2O2 degrades cell surface proteoglycans, thus rendering the membrane PL accessible to hydrolysis by exogenous PLA2. This novel mechanism introduces a role for cell surface proteoglycans in protection of cells from damage by pro‐inflammatory agents, and may assign a central role for the combined action of H2O2 and PLA2 in inflammatory and bacteriocidal processes.

The “anchored disc phenomenon”: A proposed etiology for sudden-onset, severe, and persistent closed lock of the temporomandibular joint

This article establishes a rationale for a particular type of sudden and severely restricted mouth opening caused by anchoring of the disc to the fossa termed anchored disc phenomenon, describes the possible pathogenesis of this disorder, and recommends appropriate treatment. The clinical characteristics supporting the proposed pathogenesis, and treatment of the disorder are based on data published in the literature and clinical experience with the diagnosis and treatment of this disorder.

The effect of aging on tooth morphology: a study on impacted teeth.

The effect of age on dental tissues was studied on histologic sections of totally impacted teeth obtained from patients between 11 and 76 years of age. Impacted teeth were used in order to obviate the influence of the environmental effects prevalent in the oral cavity. The presence of concentric denticles and diffuse calcifications was determined, and the width of secondary dentin, predentin, and cementum was measured. The width of predentin and cementum increased linearly with age, whereas the aging process of secondary dentin formation and diffuse calcifications followed a different pattern. The incidence of concentric denticles was identical for all age groups.