A preliminary study of manducatory behaviour influenced by stress and dental occlusion

Stress and dental occlusion often are incriminated as causes of dysfunction of the manducatory system. How and in what degree these two factors came through has not yet been clearly worked out. Our study is carried out on a group of rats presenting one or both of these two factors and we proposed to examine the duration and frequency of some components of their behaviour--intake of solid food and grooming, to detect some possible perturbations on manducatory behaviour caused by stress and/or occlusal interference. Our study shows that stress induced by emotion or occlusal interference will change the microstructure of behaviour rather than the global component in itself. This implies that we must find a clear definition of the different types of microstructure to find out which ones are changed by the two incriminating factors and which part of the behaviour component will remain stable.

The use of adhesive metal partial crowns to restore attrition defects: a case report

A patient presented with severe loss of enamel on the palatal surface of the maxillary anterior teeth, resulting from attrition. After correction of the mandibular occlusal position, the palatal defects were restored with metal partial crowns cemented with an adhesive cement. One of the six restorations dislodged during 4 years of observation, but was replaced successfully.

The rationale and indications for equilibration in the primary dentition

One type of malocclusion in the primary dentition is posterior crossbite caused by premature deflective occlusal interferences. The primary canines are the teeth that most frequently contribute to a laterally guided centric occlusion that creates a functional malocclusion. Because this is not a self-correcting situation, these types of posterior crossbites should be identified early and evaluated for possible correction through occlusal equilibration. A case that illustrates early correction of a unilateral functional posterior crossbite by equilibration and the 5-year results are presented.

Clinical diagnosis of trauma from occlusion and its relation with severity of periodontitis

The purpose of the present study was to determine the reliability of several selected signs of trauma from occlusion and their relations with severity of periodontitis. 32 moderate to advanced chronic periodontitis patients participated in the study. All teeth present were evaluated for various abnormal occlusal contacts, signs of trauma from occlusion, and the severity of periodontitis. Standardized periapical radiographs were also taken for each tooth. The results demonstrated that: (1) no significant difference occurred in probing pocket depth (PD), clinical attachment loss (AL), or percentage of alveolar bone height (BH) between teeth with and without various abnormal occlusal contacts, i.e., premature contacts in centric relation occlusion, non-working contacts in lateral excursions, premature contacts of anterior teeth or posterior protrusive tooth contacts; (2) teeth with either significant mobility, functional mobility, or radiographically widened periodontal ligament space (PDLS) had deeper PD, more AL and lower BH than teeth without these signs, while teeth with pronounced wear or radiographically thickened lamina dura had less AL than teeth without these findings; (3) 2 combined indices, i.e., the trauma from occlusion index (TOI) and the adaptability index (AI), were proposed for the identification of occlusal trauma and the response of periodontium to excessive biting forces in heavy function, respectively; TOI-positive teeth exhibit deeper PD, more AL and less osseous support than TOI-negative teeth; however, AI-positive teeth had less AL and more osseous support than AI-negative teeth; (4) with identical attachment level, TOI-positive teeth had less osseous support than TOI-negative teeth while the magnitude of difference became greater with an increase of attachment loss.

Etiologic theory and prevention of temporomandibular joint disorders: reaction paper

The treatment of patients with temporomandibular joint pain and dysfunction remains a controversial issue. Strong evidence exists that the occlusion of the teeth may not be a significant contributor to the overall etiology of the disorder. This now presents clinicians and researchers with a problem. What factors are responsible for the pain and dysfunction? Today, no solid evidence exists to substantiate the etiology of this disorder.

Etiologic theory and the prevention of temporomandibular disorders

Over the last 75 years, a variety of etiologic factors has been suggested as the cause of pain and dysfunction in the temporomandibular system. The earliest and still-popular etiologic theory proposed that temporomandibular disorders are induced by abnormal structure, usually described as a malocclusion of the teeth or jaws. The fact that this theory was based on mechanical concepts, ignored biologic diversity, and had limited factual experimental evidence to support it as well as extensive evidence in opposition did not seem to matter to its proponents. In the late 1960's and early 1970's, the structural occlusal model for TM Disorders was challenged and has yielded ground to a more multifactorial model of TMD causation. Other etiologic factors for TM disorders--such as anatomical susceptibility of TM tissues to trauma, polyarthritic diseases, joint laxity, repetitive parafunctional behaviors, and stress-related muscle dysfunction--need to be recognized and quantified. Unfortunately, many practicing dentists demonstrate a very poor understanding of and often fail to recognize these etiologic factors as agents that produce TM disorders. This failure is largely due to the fact that the dental profession has spent the last 90 years dealing with a variety of misconceptions about the etiology of temporomandibular disorders. In the 1990's, one of the more formidable challenges we face is acquiring the ability to segregate and define validly the specific TM Disorder of concern and then correctly identify and measure the specific etiologic factors that produce it. Until these problems are solved, it is unlikely that we will be able to prevent disease of the TM apparatus.

[Does occlusal overload lead to periodontal recession? Literature review]

The etiology of periodontal clefts has been widely discussed throughout the years. Trauma from the occlusion is claimed to be one of the most important causative factors. The present review of the scientific literature did, however, not show that an occlusal overload could be regarded as the main etiologic factor in gingival recessions.

Relationship between craniomandibular dysfunction and pattern of speech sound production in a series of first-graders

This report investigates associations between prevalence of functional disturbances of the masticatory system and speech disorders. The subjects were 157 children referred for speech therapy to the hospital and a control group all 130 first-graders at two elementary schools, mean age 7 years 6 months. During clinical examinations, signs and symptoms of TMJ dysfunction were recorded by the same dentist. Articulatory speech disorders were diagnosed by the same phoniatrician using the Remes Articulatory Test (Remes, 1975) for the Finnish language. The results showed that in the hospital referral group the mean value for maximal opening was smaller while laterotrusion movements and maximal protrusion of the mandible were larger than in the control group. The study group also more often had CM disorders and occlusal interferences than children of the first grade sample. In the present data, a higher frequency of subjective symptoms and several clinical signs of CMD were related to certain articulatory speech disorders. Risk of having too anteriorly-produced sounds, mainly 's'-sounds, decreased with advancing age in 6-8-year-old children. In conclusion, expression of both craniomandibular disorder and disorders in speech sound production seem to a considerable extent to reflect immaturity of fine motor control of the orofacial muscles in 6-8-year-old children.

Diagnostic tests used in determining the role of the occlusion in temporomandibular joint disorders

Two diagnostic tests, positive tenderness to palpation of the inferior bellies of the lateral pterygoid muscles and a positive stress test, are helpful in determining whether the dental occlusion is a principal etiologic factor in ischemic pain in the muscles of mastication. To avoid a noxious occlusal contact, the muscles of mastication, and particularly the lateral pterygoid muscles, must increase their activity. The ability of the patient to supply the oxygen for this activity is variable. When it is inadequate, to relieve ischemic pain the muscular activity must be decreased or the oxygen supply increased. The dentist has the option of using four modalities for the treatment of these painful muscles: physiotherapy, drug therapy, psychotherapy, and occlusal therapy. When the lateral pterygoid muscles are not tender to palpation and the stress test is negative, occlusal therapy is not indicated.

Occlusal abnormalities, pericranial muscle and joint tenderness and tooth wear in a group of migraine patients

Seventy-two migraine sufferers, whose attacks normally begin during or soon after waking from sleep, were compared with 37 age- and sex-matched controls to establish whether signs of mandibular dysfunction, occlusal discrepancies and known clenching or grinding habits were any more frequent among the former group. Temporomandibular joint tenderness or pain history, masticatory muscle tenderness and known clenching or grinding habits were found to occur at significantly increased levels in the migraine sufferers, with two-thirds of these patients reporting a parafunctional habit. Occlusal abnormalities, including non-working side or protrusive interferences and slides of greater than 1 mm to the intercuspal position, were found to occur at similar frequencies in the two groups. Assessment of wear of the occlusal surfaces also showed no difference, suggesting that any nocturnal habit with a role in migraine is more likely to be clenching in nature. In conclusion, evidence was found to support an aetiological role for nocturnal tooth clenching or grinding in migraine characterized by attacks that start predominantly during sleep or soon after waking, but no evidence of a link with occlusal factors was found in these patients.

Pattern of tooth contacts in eccentric mandibular positions in young adults

Tooth contact patterns in laterotrusion, protrusion of the mandible, and in the retruded position were recorded in young men with varying types of occlusion. The tooth contacts were recorded clinically with alginate (irreversible hydrocolloid) indices. In addition, the functional state of the masticatory system was evaluated by the recording of signs and symptoms of mandibular dysfunction and of the abrasion of the teeth. On protrusion, most subjects had contacts only on anterior teeth. Protrusive contacts only on posterior teeth were rare. On laterotrusion, most subjects had group function on the functional side. Contact on the nonfunctional side was found in half of the subjects in a 1.5 mm laterotrusive position and in one third of them in a 3 mm laterotrusive position. No correlation between the types of tooth contacts and mandibular dysfunction was found.

[Occlusion and dysfunction symptoms]

A sample of 81 students were examined for symptoms and signs associated with mandibular dysfunction. Women had a higher prevalence of these signs, which occurred statistically significant more frequently in subjects showing occlusal disturbances.

Alveolar ridge resorption and mandibular atrophy. A review of the role of local and systemic factors

Loss of alveolar bone from the edentulous jaws is a serious and common clinical problem, especially among the elderly. The retention and stability of dentures are reduced, but little is known about the pathogenesis of this bone loss. The existing data suggest that either local factors, for instance occlusal trauma, or systemic factors such as postmenopausal osteoporosis, contribute to edentulous alveolar bone resorption. This paper reviews the evidence for the aetiology of residual ridge resorption following tooth extraction.

Thielemann's diagonal law of occlusion revisited

Thielemann's studies of malocclusal relationships and the frequently observed chain reactions created in distant localities led to the formulation of a philosophical approach to occlusion that is also of practical premeditative clinical relevance for the practitioner. Dr. Thielemann presumed to name it a law, and repeated clinical observations apparently support and reinforce his claim. All disciplines of dentistry inevitably encounter and need to know about this aspect of fission-reactive involvement with the common and seemingly innocuous malocclusions. By incorporating the law into the diagnostic, planning, corrective, and therapeutic stages of treatment, the clinician can readily categorize patients for needs assessments and future goals in treatment.

Background factors in craniomandibular disorders: reported symptoms in adolescents with special reference to joint hypermobility and oral parafunctions

Correlations between craniomandibular disorders (CMD) symptoms and an inherited factor (general joint hypermobility) were studied in 193 adolescents (96 girls and 97 boys). They answered a questionnaire concerning CMD symptoms, oral parafunctions, head and jaw trauma and symptoms from other joints. Joint mobility was assessed by determining the Beighton score (0-9). Twenty-eight percent of the girls and 21% of the boys could perform four or more of the manoeuvres. Twenty-two percent of the girls and 3% of the boys were extremely hypermobile (score greater than or equal to 5). Eighty-nine percent were aware of some oral parafunction and the prevalences of oral habits were about the same in the two groups. Girls reported significantly more dysfunction symptoms than boys. No indication was found that oral parafunctions generally produced CMD but a systemic factor (joint hypermobility) seemed to play an important role when the masticatory system was exposed to local forces as in oral parafunction. This may be one explanation for the predominance of females among CMD patients.

Functional disturbances of the masticatory system in relation to articulatory disorders of speech in a group of 6-8-year-old children

In the sample of 208 children, clinical signs and symptoms of craniomandibular disorder were mild, somewhat more common in boys than in girls, and clearly more common in children referred for speech therapy than in the control group. Of variables measured in millimetres, the differences indicate sexual dimorphism rather than differences between boys and girls in the occurrence of craniomandibular disorders. The differences may also reflect later maturing of neuromuscular control in boys rather than true differences between boys and girls in the prevalence of craniomandibular disorder. Logistical regression showed that children with articulatory speech disorders had more subjective symptoms and retrusive interferences, smaller maximal opening, and larger maximal laterotrusion and protrusion movements of the mandible than the controls. Thus different dysfunctions of the orofacial region tend to coexist in the same individuals. Subjective symptoms and clinical signs are mild in 6-8-yr-old children and may reflect immaturity of fine motor control.

Myofascial pain in a young violin player: a case report

This report reviews a young patient who had undergone orthodontic therapy leaving occlusal interferences which were initially able to be tolerated. When symptoms of dysfunction arose, the general practitioner referred her to a specialist. The treatment involved a segmental bite-plane. Symptoms returned when the patient was under stress, and a Michigan splint was made as the segmental type of bite-plane is unsuitable for long-term use.

[Clinical research on the etiopathology of gingival recession]

Frequency severity of gingival recessions was studied with Stahl and Morris indices. The results showed that the localization of gingival recession was more important on the mandible (37%) than on the maxillary (27.6%) it, also demonstrated the importance of various etiologies and particularly the association of trauma - tooth malposition (81%).

Treatment of myofascial pain-dysfunction syndrome with occlusal equilibration

Fifty-three patients with a diagnosis of chronic myofascial pain-dysfunction syndrome were treated with occlusal equilibration to establish complete anterior guidance. In approximately 5 to 7 days after treatment, most myofascial pain dysfunction symptoms disappeared and complete symptom resolution was usually attained within 3 weeks. The common symptoms all patients had were (1) pain and fatigue in the masseter and temporal muscles, (2) nocturnal bruxism, (3) jaw tension on waking up, and (4) difficulty chewing some foods. All patients had an absence of true anterior guidance with molar interferences in all excursive movements. Many patients had previously undergone orthodontic therapy and had "ideal" vertical tooth relationships. Treatment consisted of occlusal equilibration to remove all posterior interferences and establish anterior guidance. Three appointments, 1 week apart, were alloted for treatment. Major symptom reduction occurred after the first appointment. Four-year follow-ups reveal no recurrence of chronic symptoms after treatment completion.

[Secondary occlusal traumatism. 1. Histopathological changes of periodontal tissues in experimental occlusal traumatism]

Six and nine months after the experimental occlusal traumatism, the following histopathological changes of periodontal tissues were observed: --Disorganisation and necrosis of the collagen fibers, abundant cellular infiltration and dilatation of the blood vasels of the periodontium; --The periodontal space was enlarged. Directions of principal collagen fibers was changed. This was especially visible in the region of transeptal fibers; --The observed periodontal changes were correlated with the duration of inflammation and occlusal trauma. The longer these factors persisted the more extensive these periodontal changes occurred.