A seven-and-a-half-year survival study of resin-bonded bridges.

A clinical trial, concerning 203 resin-bonded bridges (RBBs), was performed for investigation of the influence of retainer-type and cementation materials on the survival of these restorations. The survival rates after a 7.5-year follow-up were 75% for anterior RBBs and 44% for posterior bridges. Etched metal RBBs (E-bridges) were significantly more retentive than perforated RBBs (P-bridges); the survival rates were 78% and 63%, respectively. With respect to the cementation materials, Clearfil F, in combination with E-bridges, had the best overall survival (89%, anterior and posterior). Maxillary anterior RBBs were more susceptible to failure than mandibular anterior RBBs.

Prevalence in the Dutch adult population and a meta-analysis of signs and symptoms of temporomandibular disorder.

A nationwide survey of oral conditions, treatment needs, and attitudes toward dental health care in Dutch adults was carried out in 1986. One of the aims of the study was to assess the prevalence of signs and symptoms of temporomandibular disorder (TMD). A sample of 6577 persons (from 15 to 74 yr of age), stratified for gender, age, region, and socio-economic status, was contacted. Of this sample, 4496 persons participated in the behavioral part of the study, of whom 3526 were examined clinically. The TMD prevalence was based on (1) perceived signs and symptoms of TMD and (2) clinical examination of joint sounds, deviation, and pain on mandibular movements. A total of 21.5% of the Dutch adult population perceived some dysfunction, and 44.4% showed clinically assessed signs and symptoms of TMD. In nearly all age groups, the signs and symptoms of TMD appeared more in women than in men. Agreement between the results of the clinical examination and the anamnestic dysfunction index was significant (p < 0.0001); however, the Pearson's correlation coefficient was low (r = 0.29). The odds-value (risk-ratio) that subjects who perceived signs and symptoms of TMD would present with clinically assessed signs and symptoms of TMD was 2.3. The results of the survey were compared with results of a meta-analysis performed on 51 TMD prevalence studies. The analysis revealed (1) a perceived dysfunction rate of 30% and (2) a clinically assessed dysfunction of 44%, both based on compound samples of, respectively, over 15,000 (23 studies) and over 16,000 (22 studies) randomly selected subjects.

Demand and need for treatment of craniomandibular dysfunction in the Dutch adult population.

A nationwide survey of oral conditions, treatment needs, and attitudes toward dental health care in Dutch adults was carried out in 1986. One of the aims of the study was to investigate the perceived need and demand for treatment of craniomandibular dysfunction (CMD). A sample of 6577 persons (15-74 yrs of age), stratified for gender, age, region, and socio-economic status, was contacted. Of this sample, 4496 persons participated in the behavioral part of the study, of which 3526 were examined clinically. The CMD-treatment demand was based on (1) CMD complaints in the past, (2) CMD complaints at present, and (3) an anticipated increase of the present complaints. CMD was both anamnestically and clinically assessed, independently by different examiners. A total of 21.5% of the Dutch adult population reported dysfunction, but 85% of these perceived no need for treatment. With most of the remaining 15% either seeking or intending to seek treatment (or having had it before), a figure of 3.1% can be used to summarize the actual level of treatment need for CMD in the Dutch adult population.

Management of an anterior defect with a removable partial denture supported by implants and residual teeth: a case report.

The treatment of a patient with a major defect in the anterior region of the mandible is described. A large part of the anterior dental arch and underlying mandibular bone was involved in the defect. A removable partial denture supported by implants as well as residual teeth was used to restore the defect. Compared with a traditional removable partial denture, which was used by the patient for several years as an interim prosthesis, the application of implants resulted in improved functional comfort and stability.

Distal extension removable partial dentures supported by implants and residual teeth: considerations and case reports.

The traditional treatment for an edentulous maxilla opposed by a partially edentulous mandible with a complete denture and a distal extension removable partial denture is fundamentally inadequate. Continuing resorption of alveolar bone under the denture base of the removable partial denture causes changes in the occlusal plane. Consequently, overloading of the anterior maxillary region occurs, usually leading to increased bone resorption in the anterior maxillary ridge. Placement of implants beneath the distal extension denture base of the removable partial denture can result in a stable and durable occlusion. Two patients in whom the use of implants combined with a cast metal removable partial denture provided occlusal stability and improved functional comfort are presented.

A method to compare cost-effectiveness of dental treatments: adhesive bridges compared to conventional bridges.

The cost-effectiveness of a dental restoration depends primarily on the durability and the cost of the restoration. In this report a method is described to compare the cost-effectiveness using the durability data of adhesive bridges and conventional bridges. The study shows that, for the situation in the Netherlands, the breakeven point for equal cost-effectiveness compared to conventional bridges is achieved when the 50% survival for adhesive bridges is approximately 6.5 yr. Clinical data indicate a higher cost-effectiveness for anterior adhesive bridges. The method described in this report is considered to be useful for comparing cost-effectiveness of dental restorations in different situations.

A meta-analysis of durability data on conventional fixed bridges.

A meta-analysis was performed on the dental literature since 1970, presenting clinical data of conventional bridges. 42 publications were found that contained durability data of conventional fixed bridges. These publications dealt with 33 different samples. According to the exclusion criteria 26 studies were excluded for the meta-analysis. The data of 4118 conventional bridges were analyzed. The calculated overall survival rate was 74.0 +/- 2.1% after 15 yr.

The shortened dental arch concept and its implications for oral health care.

The minimum number of teeth needed to satisfy functional demands has been the subject of several studies. However, since functional demands--and consequently the number of teeth needed--can vary from individual to individual, this minimum number cannot be defined exactly. In general, occlusion of a complete dental arch is preferable. However, this goal might be neither attainable, for general, dental or financial reasons, nor necessary. Many studies demonstrate that shortened dental arches comprising the anterior and premolar regions can meet the requirements of a functional dentition. Consequently, when priorities have to be set, restorative therapy should be aimed at preserving the most strategic parts of the dental arch: the anterior and premolar regions. This also implies that in cases of a shortened dental arch, the prompt replacement of absent posterior molars by free-end removable partial dentures leads to overtreatment and discomfort. The shortened dental arch concept is based on circumstantial evidence: it does not contradict current theories of occlusion and fits well with a problem-solving approach. The concept offers some important advantages and may be considered a strategy to reduce the need for complex restorative treatment in the posterior regions of the mouth.

An analysis of multiple failures of resin-bonded bridges.

A clinical trial involving 203 resin-bonded bridges (RBBs) was undertaken to investigate the influence of several variables on the survival of these prostheses. This article presents the experiences with rebonded and replacement RBBs after failure of the originally bonded RBBs. A total of 62 dislodged and rebonded RBBs was included in this study and evaluated using Kaplan-Meier estimates. Rebonded RBBs that dislodged for a second time were replaced by another type of RBB ('replacement' RBBs, n = 32). The study revealed that rebonded RBBs were more susceptible to dislodgement than originally bonded RBBs. Fifty per cent survival was reached 2.1 years after rebonding. The sooner the first dislodgement occurred, the lower the retention rate of the rebonded RBB (PH-model, beta = 0.78, P = 0.02). Also some failure characteristics were evaluated. Failure characteristics (i.e. fracture site and partial versus complete dislodgement) of first and second dislodgement were not correlated (Chi-square, P values > 0.25). The survival of 'replacement' RBBs was significantly better than the survival of multiply failure RBBs (median survivals respectively 1.6 years and 1.0 year, P = 0.03). From the results of this study it may be concluded that the survival rates of rebonded and replacement RBBs were unacceptable.

An analysis of durability data on post and core restorations.

An attempt was made to review the dental literature since 1970, presenting clinical data of posts and core restorations, by the use of a meta-analytic procedure. Fourteen publications were found that contained durability data on post and core systems. According to the exclusion criteria 11 studies were excluded for further analysis of the data. The survivals of these studies varied from 98.6% survival after a follow-up period of more than 10 years (F.S. Weine et al. 1991, J. Endodont. 17, 293-297) to 77.6% survival after a mean follow-up period of 5.2 years (D.H. Roberts, 1970, Br. Dent. J. 128, 117-124). The data of the three selected studies were reconstructed according to the method of Kaplan-Meier but could not be combined for an overall survival assessment because the study characteristics were too heterogeneous. Therefore the survivals were presented separately. The reconstructed survivals of the studies after 6 years were 81% survival (standard error 6%) for resin composite build-ups in combination with screw posts and 91% survival for two studies including cast posts and cores (standard errors respectively 3% and 2%). Although it was not meaningful to combine the data for an overall survival, the meta-analytic method of this study revealed homogenic survival data and as such the followed procedure is considered to be an appropriate method to obtain insights in clinical durability data.

Shortened dental arches and masticatory ability.

In a previous study concerning oral function with shortened dental arches, it was found that approximately 10 per cent of the patients investigated complained of impaired masticatory ability despite a substantial reduction in arch length and, as a consequence, food platform area. This finding differs from those of studies relating masticatory performance to food platform area. From a review of pertinent literature, it is concluded that impairment of masticatory ability is manifest when less than 10 occluding pairs of teeth are present. Shortened dental arches are not associated with shifts in food selection adversely affecting general health.

How much reduction of the dental arch is functionally acceptable for the ageing patient?

Dental care should be aimed at the preservation of a natural functioning dentition for life, within the available resources. In general, preference should be given to dentitions comprising complete dental arches or 14 occluding pairs of teeth. However, in many subjects--such as the elderly--this goal might be neither attainable nor necessary. In these cases, dental care should be aimed at preserving the strategic parts of the dental arch, which are the front and premolar regions (the so-called ultimate occlusal preservation target). Clinical observation as well as research findings indicate that elderly people can function at an acceptable level with a reduced dentition consisting of 10 or even fewer occluding pairs. The minimum size of a functional dental arch differs between individuals and depends on local and systemic factors. Important indicators are the age, the (periodontal) quality of the remaining dentition, the spatial relationship between the lower and upper teeth, the occlusal activity and the adaptive capacity. Dental health care systems should implement guidelines to concentrate the available resources primarily on the strategic regions of the dental arch, especially in high-risk groups. These guidelines should be based on research results. The main objective of this paper is to contribute to defining an acceptable oral status for elderly subjects.

Preventive goals in oral implantology.

Preventive dentistry is mainly concerned with caries and periodontal disease and little or no attention is paid to the prevention of alveolar bone loss. An overdenture contributes to the preservation of alveolar bone and offers a number of advantages in comparison to a conventional complete denture. After tooth extraction the atrophy of edentulous lower jaws can be prevented or delayed by using implants supporting an overdenture or a fixed mandibular prosthesis. Hydroxyapatite implants have been studied as submerged tooth root substitutes and have proven to be able to preserve the bulk of the alveolar ridge. A drawback of this submucosal implant is that the ridge maintenance depends solely on the physical presence of the hydroxyapatite implants. If implants support an overdenture or a fixed prosthesis they also play a role in maintaining the function of the bone in the different stages of reduction of the mandible. In this paper a classification for the different resorption stages of the mandible is presented and is used to determine the correct moment for preventive implantology. In addition the use of a lingualised occlusion is discussed as a contribution to the preventive goals in oral implantology.

Needs for tooth replacement.

The prime objective of dental care is maintaining a natural functional dentition for life. It is expected that a growing group of adults will keep their dentition into old age. Although routine prosthodontic care will still be important in the future the treatment strategy for older adults and elderly people with a reduced dentition does require a different approach. The traditional approach in prosthetic therapy was guided primarily by morphological criteria aimed at preservation of complete dental arches, which resulted in emphasis on quantity in dental care. Nowadays requirements such as aesthetics and functional comfort are considered more important and more easily achieved. In the presented principles for treatment planning the importance of a thorough preliminary treatment is stressed. Furthermore, needs for tooth replacement are discussed and guidelines are given for a preventive prosthodontic treatment approach in severely broken-down dentitions and edentulous patients.

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.

Porosity in resin composite core restorations: the effect of manipulative techniques.

Forty acrylic resin duplicates of an endodontically treated and extracted human molar were restored with two resin composite materials for core restorations. Two different manipulation techniques, bulk insertion and syringe application, were used. In a simulated clinical setup, the core buildups produced by the different manipulation techniques were investigated for voids. In 20 duplicates, a post was placed to simulate a metal post and resin composite core buildup. The syringe technique produced significantly fewer incorporated voids for both resin composite core materials than did the bulk insertion technique. It was not possible to demonstrate a relationship between the presence of voids and the presence of a metal post.

[Partial models in fixed prosthodontics]. / Partiële modellen, indicatie en aandachtspunten.

In general there is consensus regarding the required criteria for crown- and bridge restorations. However, the variety in methods used for their fabrication is large. Textbooks and courses tend to advocate the use of full arch impressions without supplying objective data indicating better clinical behaviour of these restorations compared with the use of quadrant impressions. This article presents advantages, disadvantages, indication and essential steps when using quadrant models.

[Occlusion repair or occlusion loss? Results of preliminary treatment as the starting point]. / Occlusieherstel of occlusieverlies? Resultaat van voorbereidende behandeling geldt als uitgangspunt.

Epidemiological data confirm that the number of elderly with an impaired dentition is increasing. The treatment of patients with an impaired dentition should be focused on maintaining oral function during life-time. However this goal is hardly achievable because of the complicating factors in an impaired dentition. This article describes the Nijmegen Dental School approach in the treatment of impaired dentition and stresses the importance of the preliminary treatment in order to answer the question whether restoring or extracting teeth is the most appropriate treatment modality.

[The clinical behavior of metal-composite post and core build-up. Results of a pilot study]. / Het klinisch gedrag van metaal-composiet stiftopbouwen. Resultaten van een pilot-studie.

During the period 1974-1986 112 post and core buildups were inserted in 74 patients. The buildups consisted of a metal prefabricated post (Dentatus, Unimetric or Radix) in combination with a composite core. After an average follow-up period of 7.9 years 14 failures (12.5%) were noticed. Eight teeth could be rerestored and six teeth had to be extracted. However, when correction was made for teeth with a bad initial prognosis and for extractions not related to the buildup restoration, eight failures remained caused by failure of the buildup (7.5%). Half of these concerned Dentatus posts.

[Fit of anchors in frame prostheses]. / Pasvorm van ankers bij frameprothesen.

The fit of clasps was assessed in 101 removable partial dentures (RPD), including 54 free-end prostheses without any tooth bound replacements and 47 tooth bound prostheses replacing only premolars and molars. The age and the design of the RPD had a significant influence on the fit: in older and in stress broken free-end RPD's the clasps had a worse fit in terms of standing away from the abutment tooth.