Gunnar E. Carlsson

Bite force and state of dentition.

The maximal bite force and the strength of the finger-thumb grip of 125 Skolt Lapps, aged 15 to 65, was measured with a specially devised apparatus. The bite force was measured with the biting fork placed between the first molars and between the incisors, respectively. The finger-thumb grip was measured by letting the subject press the prongs of the fork between the thumb and forefinger of each hand as hard as possible. The range of inter-individual variation of the maximal bite force and finger-thumb grip was great. The mean values were higher for the males than for the females. In the males the maximal bite force thus measured in the molar region was 39 kg (382 N) and 18 kg (176 N) in the incisor region. The corresponding values for the females were 22 kg (216 N) and 11 kg (108 N). The finger-thumb grip strength for males was, on the average, 10 kg (98 N); that of the females, 7 KG (69 N). The average difference in bite force between the men and the women was larger in the group with natural teeth than in the one with complete dentures. The values found for the bite force decreased with increasing age, especially for the females. Most of this reduction with increasing age was probably due to the age-dependent deterioration of the dentition. In both sexes the bite force was notably smaller among the denture wearers than among the dentate persons. The number of natural teeth varied closely with the bite force, i.e. the greater number of natural teeth the greater the bite force.

Bone resorption around fixtures in edentulous patients treated with mandibular fixed tissue-integrated prostheses

Bone loss around osseointegrated titanium fixtures supporting mandibular fixed prostheses has been measured by means of stereoscopic intraoral radiography. Forty-six patients treated with the osseointegration implant method according to Brånemark have been followed for an observation period of up to 6 years. The bone loss was small, approximately 0.5 mm during the first postsurgical year and thereafter 0.06 to 0.08 mm annually. Poor oral hygiene and clenching of teeth significantly influenced bone loss. More bone was lost around the medial fixtures than around the more posterior ones.

Functional disorders of the masticatory system. I. Distribution of symptoms according to age and sex as judged from investigation by questionnaire.

A random sample of every 35th individual, aged 15–74 years, and residing in the Swedish city of Umei was investigated by questionnaire regarding the frequency of functional disorders of the masticatory apparatus and certain associated factors. of the 1, 215 persons invited, 1, 106 (91 %) cooperated. Facial pain and headache was reported by 24 %. Pain on gaping was localised mainly to the temporomandibular area and wasnoted in 12 %, equally often in miles as in females. the range of movement of the mandible was reported as impaired by 7 %, and somewhat more often by females than by males. Clicking and crepitation of the temporomandibular joints was reported by 39%, somewhat more often by females. Women also had presently and earlier symptoms of dysfunction of the masticatory system more often and had sought advice more often, than men. Pain on movement of the mandible was more common among younger individuals, while other symptoms of dysfunction were relatively equally common in all age groups. Oral parafu...

Chewing efficiency and state of dentition. A methodologic study.

Chewing efficiency, defined as the ability to grind a certain portion of a test food during a given time, was tested in 139 Skolt Lapps, ages 14-65. 94 persons had natural teeth and the remaining 45 wore dentures (partial and/or complete). The test food was almonds. Number of chewing strokes, swallowings and chewing time was denoted. The chewing efficiency was classified after a scale from 1 to 5 where 1 meant very good and 5 very poor ability to reduce the particle size of the test food. Clear associations were found between chewing efficiency and dental state. Number of occluding pairs of teeth was closely correlated with chewing efficiency and individuals with less than 20 teeth had a higher index score than those with more than 20 teeth. The values noted for number of chewing strokes, swallowings and chewing time were smaller for those with a good chewing efficiency, but the variation was not linear and not always significant. Denture wearers had statistically significantly higher chewing efficiency score than those with natural teeth, without dentures, and needed more chewing time before swallowing.

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 a 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.

Chewing Ability in Relation to Dental and General Health

Answers were obtained from 1106 (91 %) of a randomly selected sample of persons, aged 15–74 years, who were sent a questionnaire on chewing ability, chewing habits and some general and oral disorders. The questionnaire revealed that chewing ability was closely correlated to the number of residual teeth, but a loss of up to 7 teeth did not seem to entail an assessment of impairment. One fourth of the complete denture wearers reported that they could not chew all sorts of food. Unilateral chewing was reported by about one third, was more frequent in individuals with an unequal distribution of teeth and was correlated to impaired chewing ability. Both reduced chewing ability and unilateral chewing was closely correlated to increasing number of symptoms of dysfunction of the masticatory system. In all age-groups reduced chewing ability and unilateral chewing were reported more frequently by people who considered their general state of health impaired than by the healthy subjects.

A prospective investigation over two decades on signs and symptoms of temporomandibular disorders and associated variables : A final summary.

The aim of this summary of a longitudinal investigation on temporomandibular disorders (TMD) was to present the prevalence figures of signs and symptoms of TMD and certain other examined variables, and the correlations between these variables, over a 20-year period. Originally, 402 randomly selected 7-, 11-, and 15-year-olds were examined clinically and by means of a questionnaire. The same examination procedure was repeated three times: after 4–5 years and after 10 and 20 years, respectively. Signs and symptoms of TMD were mainly mild, but common already in childhood. They increased up to young adulthood, after which they leveled out. Progression to severe pain and dysfunction was rare, and spontaneous recovery from more pronounced symptoms was also rare. Significant correlations between reported bruxism and TMD symptoms were found, and a baseline report of tooth-grinding was a predictor of TMD treatment during the 20 years covered by the investigation. Occlusal factors were only weakly associated with TMD signs and symptoms. However, a lateral forced bite between the retruded contact position (RCP) and the intercuspal contact position (ICP) and a unilateral crossbite deserve further consideration as possible local risk factors for development of TMD. In conclusion, a substantial fluctuation of TMD signs and symptoms was observed in this sample of Swedish subjects followed for 20 years from childhood to adult. The demand for TMD treatment was low at all examinations, while the estimated treatment need was larger. One-third of subjects who had some kind of orthodontic treatment did not run a higher risk of developing TMD later in life.

CLINICAL MORBIDITY AND SEQUELAE OF TREATMENT WITH COMPLETE DENTURES

Wearing complete dentures may have adverse effects on the health of both the oral and the denture-supporting tissues. This article is a review of selected literature on the sequelae of treatment with complete dentures in the specific areas of residual ridge resorption, mucosal reactions, burning mouth syndrome, temporomandibular disorders, and patient satisfaction. Recent literature found with a Medline search from 1952 to 1996 is included in this review. Residual ridge resorption is an inevitable consequence of tooth loss and denture wearing, with no dominant causative factor having been found. Mucosal reactions have a multifactorial cause, most of which can be easily treated. Most patients are satisfied with their complete dentures. Correlations between anatomic conditions and denture quality and patient satisfaction are weak. Psychologic factors seem to be extremely important in the acceptance of and adaptation to removable dentures. There are still no reliable methods to predict the outcome of complete denture treatment and there are many problems related to treatment with complete dentures. Although the prevalence of an edentulous condition is decreasing, the great number of edentulous people warrants the continuing efforts of basic and clinical research on removable partial dentures. Complete denture prosthodontics will remain an important part of dental education and practice. In addition to clinical and technical skills, insight into patient behavior and psychology and communication techniques are also necessary.

A 20-year longitudinal study of subjective symptoms of temporomandibular disorders from childhood to adulthood

The aims were to study the development over 20 years of reported temporomandibular disorders (TMD) symptoms in an epidemiologic sample and to analyze possible correlations between these symptoms and some other variables. Four hundred and two randomly selected 7-, 11-, and 15-year-old subjects were originally examined by means of a questionnaire with regard to symptoms of TMD. The investigation was repeated after 4-5, 10, and 20 years, using the same method. After 20 years, when the original group had reached the age of 27 to 35 years, 378 individuals (94%) could be traced, and they were sent a questionnaire. Three hundred and twenty subjects (80% of the original sample, 85% of the traced subjects) completed and returned the questionnaire. There was a substantial fluctuation of reported symptoms over the 20-year period. Progression to severe pain and dysfunction of the masticatory system was rare. On the other hand, recovery from frequent symptoms to no symptoms was also rare. At the last examination 13% reported one or more frequent TMD symptom. The prevalence of bruxism increased with time, but other oral parafunctions decreased. Women reported TMD symptoms and headache more often than men. Correlations between the studied variables were mainly weak. The highest correlations found (rs = 0.4-0.5) were those between reported tooth clenching and tooth grinding and jaw fatigue. It can be concluded that in this epidemiologic sample, followed over 20 years from childhood to adulthood, a substantial fluctuation of TMD symptoms was found. Severe symptoms were rare, but 1 of 8 subjects reported frequent TMD symptoms at the last exam.

Thickness of the soft tissue layers and the articular disk in the temporomandibular joint.

Out of 115 right temporomandibular joints from Swedish subjects aged 1 day to 93 years, 48 joints without any gross sign of arthrosis or deviation in form were examined histologically. The joint components were cut sagittaly, each into four parts. Histological sections were made of the condyle, the temporal component and of the articular disk. The total thickness of the soft tissue layers was measured in decalcified sections, cut from the medio-central and lateral parts of the condyle and the temporal component and from the medial, medio-central, latero-central and lateral regions of the disk. In the medio-central sections from the condyle and temporal component the thickness of the fibrous connective tissue layer i.e. the surface layer was also registered. The soft tissue layers were thickest in the condyle superiorly, about 0.4-0.5 mm, in the temporal component on the postero-inferior slope of the articular tubercle, about 0.5 mm, and in the disk posteriorly about 2.9 mm. In the roof of the fossa it was only 0.1 mm. The soft tissue layers on the condyle as well as the disk were thinner laterally while the corresponding tissue in the temporal component was thicker laterally. The thickness of the soft tissue layers seem to reflect the growth and functional load to which the joint is exposed.