Rehabilitation of biting abilities in patients with different types of dental prostheses

Necessity of keratinized tissues for dental implants: a clinical, immunological, and radiographic study

BACKGROUND

Necessity of keratinized tissues (KTs) for maintaining health around dental implants (DIs) remains as a controversial issue.

PURPOSE

The aim of this study was to investigate the effects of KT width (KTW) on peri-implant tissues by evaluating peri-implant clinical and inflammatory parameters.

MATERIALS AND METHODS

Sixty DIs were included in this 6-month longitudinal study. After classifying DI based on the presence of KTs at the buccal aspect as with adequate/inadequate KTW, DIs were randomly assigned into three study groups. In the first group, while free gingival graft (FGG) was performed, DIs in maintenance (M) group were followed up by standardized maintenance procedures at baseline, first, third, and sixth months as with DI with adequate KTW (Control). Clinical parameters, peri-implant sulcular fluid (PISF) volume, PISF Interleukin 1β concentration, and bone loss were analyzed.

RESULTS

Significant improvements in clinical and immunological parameters were noted only for FGG for the whole study period. Statistical differences detected between the treatment groups (FGG vs M) were for gingival index at all time points and for PISF volume at sixth month. For the other parameters evaluated, while lower values were observed for FGG, statistically no differences were noted between the groups.

CONCLUSIONS

Based on the results of this study, it can be suggested that FGG performed around DIs lacking KT is a reliable method, leading to significant improvements in clinical and inflammatory parameters. Further long-term studies including more DIs are needed to clarify the role of KT on maintenance of DIs.

Dental status and incident falls among older Japanese: a prospective cohort study

OBJECTIVE

To examine if self-reported number of teeth, denture use and chewing ability are associated with incident falls.

DESIGN

Longitudinal cohort study (the Aichi Gerontological Evaluation Study).

SETTING

5 Japanese municipalities.

PARTICIPANTS

1763 community-dwelling individuals aged 65 years and older without experience of falls within the previous year at baseline.

MAIN OUTCOME MEASURES

Self-reported history of multiple falls during the past year at the follow-up survey about 3 years later. Baseline data on the number of teeth present and/or denture use and chewing ability were collected using self-administered questionnaires. Logistic regression analyses controlled for sex, age, functional disability during follow-up period, depression, self-rated health and educational attainment.

RESULTS

86 (4.9%) subjects reported falls at the follow-up survey. Logistic regression models fully adjusted for all covariates showed that subjects having 19 or fewer teeth but not using dentures had a significantly increased risk for incident falls (OR 2.50, 95% CI 1.21 to 5.17, p=0.013) compared with those having 20 or more teeth. Among subjects with 19 or fewer teeth, their risk of falls was not significantly elevated so long as they wore dentures (OR 1.36, 95% CI 0.76 to 2.45, p=0.299). No significant association was observed between chewing ability and incident falls in the fully adjusted model.

CONCLUSIONS

Having 19 or fewer teeth but not using dentures was associated with higher risk for the incident falls in older Japanese even after adjustment for multiple covariates. Dental care to prevent tooth loss and denture treatment for older people might prevent falls, although the authors cannot exclude the possibility that the association is due to residual confounding.

Factors affecting wear of composite resin denture teeth--24-month results from a clinical study

The objectives of this study were to measure the occlusal wear of composite resin denture teeth in patients wearing a complete denture and to evaluate factors affecting wear. Fifty participants provided with complete dentures in at least one jaw were included. Gypsum casts were made from preliminary vinyl polysiloxane impressions 4 weeks after insertion, then after 6 (t(1)), 12 (t(2)), and 24 months (t(3)). Three-hundred and three posterior denture teeth were evaluated after 24 months. Wear was measured indirectly, from the casts, by means of a three-dimensional laser scanner device. Sequential images of the occlusal surfaces were digitized and superimposed (occlusal matching). Statistical analysis was performed by the use of mixed regression models, with the patient being a random effect. Mean wear (median, interquartile range; micrometer) of the entire occlusal surface was 8 (19) at t(1), 18 (34) at t(2), and 40 (61) at t(3). Maximum vertical loss (median, interquartile range; micrometer) was 92 (112) at t(1), 146 (148) at t(2), and 226 (184) at t(3). The dental status of the opposing jaw and the nature of the opposing material significantly affected the wear of denture teeth at t (3). Gender, daily wearing time, jaw, and type of tooth had no significant effects on the extent of wear. Clinically relevant vertical loss of composite resin denture teeth occurs after 24 months. Considering the limitations of this study, wear of denture teeth was affected by dental status and opposing material. The results suggest that wear of composite resin denture teeth exceeds that of enamel.

Verificação e análise morfofuncional das características da mastigação em usuários de prótese dentária removível

OBJETIVO: verificar as características da mastigação em indivíduos usuários de prótese dentária removível parcial e total, analisando prováveis fatores interferentes associados à função mastigatória. MÉTODOS: participaram 53 indivíduos, ambos os sexos, entre 42 anos e 67 anos, divididos em dois grupos: 32 indivíduos usuários de prótese dentária total e/ou parcial removível estável (G1) e 21 indivíduos com dentição natural (G2). Foram critérios de exclusão: deficiência neurológica ou cognitiva, deformidades dentofaciais, disfunção temporomandibular e qualquer lesão bucal que pudesse interferir na mastigação. A avaliação foi realizada com pão de sal, solicitando-se mastigação habitual. Foram analisados: características das estruturas e da musculatura, tipo de corte, manutenção de vedamento labial, tempo de mastigação, número de ciclos mastigatórios, e tipo de mastigação: se uni ou bilateral, considerando-se predomínio unilateral em mais de 66% dos ciclos mastigatórios em um único lado. RESULTADOS: foram verificadas alterações quanto à característica do músculo masseter e ao tipo de corte para G1 com diferenças estatisticamente significantes, quando comparado à G2. As demais estruturas orofaciais, lábios, língua, bochechas, mentual, e postura de lábios durante a mastigação apresentaram-se normais para ambos os grupos. Não houve diferença significante entre os grupos quanto aos movimentos mandibulares, ao tipo, tempo e número de ciclos mastigatórios e caracterização da deglutição. CONCLUSÃO: a mastigação em usuários de prótese dentária removível caracteriza-se por alterações no corte do alimento, indefinição de tipo mastigatório, vedamento labial satisfatório, média do tempo e de ciclos mastigatórios semelhantes àqueles obtidos para indivíduos com dentição natural.

Bite force and electromyograpy during maximum unilateral and bilateral clenching

Maximum voluntary bite force has often been studied as an indicator of the functional state of the masticatory system. Bilateral, as well as unilateral, methods have been used to determine bite force. Only a few studies have compared the outcomes of both methods. The aim of this study was to measure bite force and jaw-muscle activity during bilateral as well as unilateral maximum clenching in a large number of healthy subjects, so that the results could be compared. In a group of 81 dentate subjects we observed an average bilateral bite force of 569 N. The average unilateral bite force was significantly lower, being 430 N (right) and 429 N (left). Masseter and anterior temporal muscle activities were also significantly lower during unilateral clenching as compared with bilateral clenching. The masseter muscles showed no difference in activity between the ipsilateral side and the contralateral side during unilateral clenching. In contrast, the activity of the anterior temporal muscle on the ipsilateral side was significantly higher than on the contralateral side. Thus, the change in the forces acting on the jaw during unilateral clenching compared with bilateral clenching leads to a different response in the temporal muscles than in the masseter muscles.

Correlation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of therapy

AIM

The association between periodontal status and biting force is unclear. The aim of this study was to investigate the relation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of periodontal treatment.

MATERIAL AND METHODS

A total of 198 patients, who had entered a periodontal maintenance programme, were examined for the presence of restorations on the occlusal surface, probing pocket depth, clinical attachment loss (CAL), bleeding on probing, and mobility of teeth. Quantitative analysis of total biting force, occlusal contact area and biting pressure (defined by biting force per 1 mm(2) of occlusal contact area) was performed using microcapsular pressure-sensitive sheets.

RESULTS

A multiple stepwise regression analysis showed that total biting force and occlusal contact area were positively associated with the number of present teeth and negatively associated with female gender, mean CAL and mean probing pocket depth. Biting pressure was positively associated with CAL.

CONCLUSIONS

Reduced periodontal support was found to be associated with decreased total biting force and with increased biting pressure (defined as force per 1 mm(2) of occlusal contact area).

The bases for using a particular occlusal design in tooth and implant-borne reconstructions and complete dentures

OBJECTIVES

A systematic review identified randomised and other trials (1966-2006) of studies of occlusal design of crowns, complete (CRP) and partial (PRP) removable prostheses and implant-borne reconstructions, and whether occlusal design influenced diet, quality of life, bruxism and attrition.

METHODS

The search primarily included Cochrane Database of Systematic Reviews and Central Register of Controlled Trials, Database of Abstracts of Reviews of Effectiveness, Ovid Medline and PreMedline.

RESULTS

The search yielded 1315 studies: 20 on CRP--1 RCT, one systematic review, four clinical trials, 10 case series; 22 on PRP - one cohort study, two experimental studies, 15 case reports or case series, three clinical trials; 23 on implant superstructures, and 24 reports on implant failure, 37 on oral health related quality of life, eight on attrition; and four studies on masticatory function.

CONCLUSIONS

CRP--Studies of occlusal form and tooth arrangements, included balanced, lingualised and monoplane arrangements--lingualised posterior occlusion was preferred. Early studies on CRP design were observational as case reports, however data suggested that optimum function is achieved by modification of the maxillary occlusion, irrespective of the opposing mandibular occlusion. PRP--Edentulous ridge resorption is patient-specific, has a multifactorial aetiology and there is no objective data to confirm that mechanical factors cause bone loss; oral hygiene management is crucial for long-term health. Studies on distal extension PDs confirmed a link between bite force and masticatory function; preservation of two functioning posterior tooth units ipsilateral to the distal extension optimises function. Data indicate that patient-specific factors, rather than PD design-specific features, influence long-term PD outcomes. Implant superstructures--There is little scientific evidence specifying occlusal and superstructure design for fixed prostheses for teeth or implants. Occlusal scheme design and occlusal form have evolved through clinical experience, but there is no evidence to indicate that a particular design is superior. Complex neurophysiological mechanisms allow the jaw muscle system to accommodate to oral and dental changes.

Clinical wear of posterior metal-free polymer crowns. One-year results from a randomized clinical trial

OBJECTIVES

The purpose of this randomized clinical trial was to evaluate the clinical wear behavior of posterior, metal-free polymer crowns, with and without a glass-fiber framework, and to compare it with that of metal-ceramic crowns.

METHODS

Eighty single crowns manufactured from a newly designed polymer composite were set in posterior teeth. Half of these received a glass-fiber framework (group 1) whereas half were prepared without framework stabilization (group 2). All polymer crowns were adhesively luted with resin cement. As the control group, 40 conventional metal-ceramic crowns were inserted with hybrid cement. Wear was measured, by use of gypsum replicas, at baseline and after 12 months, by use of a 3D laser scanner. Statistical analysis was performed using mixed-effects regression model analyses.

RESULTS

The mean total wear of posterior single crowns was -8.1 microm (+/-9.7 microm) in group 1, -7.0 microm (+/-9.1 microm) in group 2, and -3.4 microm (+/-6.3 microm) in the control group. Statistical analysis revealed wear behavior was significantly different from the control group for group 1 (p=0.014) and group 2 (p<0.01). No significant difference was detected between groups 1 and 2. Age, gender, and opposing teeth had no significant effect on wear behavior.

CONCLUSIONS

Within a 12-month observation period mean total wear of posterior polymer crowns with and without a glass-fiber framework was significantly greater than for metal-ceramic crowns. The selection of restorative materials should be based on knowledge of clinical wear in order to preserve occlusal stability.

The effect of periodontitis on biting abilities

BACKGROUND

The aim of this study was to compare the biting abilities (bite force [BF] and occlusal contact area [OCA]) of chronic periodontitis patients with those of control patients with healthy periodontia by using pressure-sensitive sheets.

METHODS

The study population consisted of 20 patients with chronic periodontitis whose initial periodontal therapy was completed and 20 control subjects with healthy periodontia. Periodontitis was diagnosed by radiographs and measurements of probing depth and clinical attachment level. Pressure-sensitive sheets were used for the quantitative analysis of BF and OCA.

RESULTS

Both mean BF and OCA values were greater in the healthy control group compared to those of the study group. The differences between the groups were statistically significant at the 95% confidence level.

CONCLUSION

Reduced periodontal support in the absence of inflammation negatively affected biting abilities.

Factors Associated with Masticatory Performance in Unilateral Distal Extension Removable Partial Denture Patients

PURPOSE

Masticatory performance of denture patients is an outcome of the intricate inter-relationship between patient characteristics and denture construction. This study aimed to identify both patient- and denture-related factors associated with masticatory performance in unilateral distal extension removable partial denture patients (RPDs).

MATERIALS AND METHODS

Seventy-two patients (25 male and 47 female, mean age 63.4 +/- 6.7 years) with unilateral distal extension RPDs were included in the study. The Mixing Ability Index (MAI) obtained from a chewing test using standard two-colored wax cubes, determined masticatory performance. The effect of each evaluated factor on masticatory performance was first determined by an independent t-test or one-way analysis of variance. The statistically significant factors were entered in a model of multivariate linear regression analysis to estimate the independent effect on MAI.

RESULTS

The MAI ranged from -3.06 to 0.80 (Mean -0.71 +/- 0.86). Univariate analyses identified male gender, high maximum bite force, more functional tooth units, and natural dentition opposing RPDs as patient factors increasing the MAI. Multivariate analysis (adjusted R(2)= 0.346) revealed that gender (p < 0.001), maximum bite force (p= 0.02), and number of functional tooth units (p= 0.03) were independent predictors for masticatory performance. None of the denture-related factors had a significant influence on MAI.

CONCLUSION

Gender, maximum bite force, and number of functional tooth units were the main factors influencing masticatory performance of unilateral distal extension RPD patients.

Association of bite force with ageing and occlusal support in older adults

OBJECTIVES

The purpose of this study was to investigate the effect of ageing, occlusal support and TMJ condition and general health status on bite force in older adults.

METHODS

The study sample consisted of 850 independently-living people over the age of 60 years. Bilateral maximal bite force in the intercuspal position was measured with pressure sensitive sheets. TMJ noise by palpation and limitation of mouth opening (less than 40 mm) were assessed. Subjects were grouped into three categories by occlusal support according to the Eichner Index.

RESULTS

A multiple logistic regression analysis showed that whether participants had low bite force or not was significantly associated with gender, age, self-rated general health and occlusal support, but not TMJ noise or mouth opening limitation. Overall bite force showed a statistically significant but weak negative Spearman's correlation with age (r=-0.24, p<0.001). However, there was no significant correlation between age and bite force in the Eichner C group for males or in any of the Eichner classification for females.

CONCLUSIONS

Decline of occlusal support and general health might translate into reduction of bite force with ageing in older adults. Since tooth loss is not physiological ageing but pathological ageing, it cannot be shown that reduction of bite force is a natural effect of ageing.

Implant-supported edentulous maxillary obturators with milled bar attachments after maxillectomy

PURPOSE

The purpose of this study was to evaluate the clinical results of implants and milled bar supported edentulous maxillary obturators following the surgical ablation of maxillary tumors.

PATIENTS AND METHODS

Seven patients with malignant tumors of the maxilla were studied. All patients underwent partial or total maxillectomy. Implants were installed in the remaining maxilla and milled bar supported obturators were fabricated. Masticatory efficiency, biting abilities, speech function, and changes in the marginal bone level around the implants were evaluated without the prostheses, with the previous prostheses, and with the implant-supported prostheses.

RESULTS

All implants were osseointegrated. All patients wore milled bar supported obturators and masticatory and speech functions markedly improved. There was no complication during the follow-up period.

CONCLUSIONS

These results suggest that a maxillary obturator supported by milled bar attachments is useful for oral rehabilitation in patients with resected edentulous maxilla.

APPLICATION OF "PRESCALE" AS AN AID TO CLINICAL DIAGNOSIS IN ORTHODONTICS

We examined the feasibility of applying the Dental Prescale Occluzer System to the evaluation of occlusion in orthodontic patients. The patients were classified according to the type of malocclusion or facial pattern. The values of occlusal contact area and occlusal force obtained from these individuals differed depending on the type of occlusion or facial pattern. These values were higher in individuals with normal occlusion than in patients with malocclusion and higher in patients with the Brachyo facial pattern than in those with the Dolico facial pattern. Because this system can very easily analyze the occlusal contact area, the mean pressure on each occlusal contact point, and the occlusal force during the process of orthodontic treatments, it can be useful as an aid for the initial diagnosis of occlusal problems, the observation of the changes in occlusion during treatment, and the establishment of the final goal of orthodontic treatments.

Correlation between periodontal status and biting ability in Chinese adult population

This study investigated the relation between periodontal condition and biting ability in a Chinese population using the pressure-detecting sheet. A total of 142 subjects residing in Nanchang, Jiangxi province, China, participated in the study. The examination included probing pocket depth (PD), clinical attachment level (CAL), bleeding on probing and coronal caries teeth. Biting abilities per person, biting force, biting pressure and occlusal contact area were measured using the sheet. Number of teeth present showed positive correlation with biting force and occlusal contact area, but were negatively correlated with biting pressure. No significant correlation was observed between the mean PD, percentage of pocket > or = 4 mm, bleeding index and any of biting abilities. The mean CAL showed a significantly negative correlation with biting force and occlusal contact area. Multiple stepwise regression analysis selected the number of teeth present, sex and age as the significant factors affecting the biting ability. However, no periodontal indices were picked up as the significantly contributing factor. There appears to be little effect of periodontal condition on biting ability. Ageing was selected as a contributing factor to reduction in the Chinese adults, but not in the Japanese population.