The survival rate of bridges. A study of 1674 bridges in 40 Dutch general practices.

The survival rate of 1674 bridges and the influence of several factors on the lifetime of bridges were analysed, based on data from patient records that belonged to a random sample of 40 Dutch general practices. It appears that the 12 year survival rate of the bridges is 87%. There is a significant difference in the survival rate between the bridges that meet and do not meet Ante's law, and only a weak significant difference between the bridges with vital vs. non-vital abutment teeth. Gender and age of the patient, length of the bridge, presence of a post and core build-up, or the construction of the bridge (conventional fixed vs. cantilever pontic) appear to have no influence on the survival rate of the bridges in this sample.

Clinical performance of different post and core systems--results of a pilot study.

During the period 1974-1986, 112 post and core build-ups were inserted in 74 patients. The build-ups 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 build-up restoration, eight failures remained caused by failure of the build-up (7.5%). The Dentatus posts seemed to increase the risk for failure.

[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.

Bridges in general dental practices: a descriptive study of the types of bridges and patients.

Based on data from patient records from a random sample of Dutch general practices, a study was made of the bridge distribution pattern in different patient groups. Patient variables such as age, sex and insurance type were analysed. More women had a bridge inserted than men. However, there appeared to be no difference in the average quantity of bridges in men or women. The abutment teeth most frequently used were the cuspids in the maxilla and the second premolars and second molars in the mandible. Fourteen percent of the bridges consisted of five or more units, 14% were free-end bridges, 13% did not meet Ante's law and 16% had one or more non-vital abutment teeth.

Survival studies of dental restorations: criteria, methods and analyses.

The longevity of dental restorations is an important health concern for the patient, the dentist, and the various forms of insurance systems. In this article several methods of evaluating survival time are described and the different ways of presenting the findings of survival studies are discussed. It is stated that only longitudinal studies are appropriate to give an exact insight in the longevity of restorations. A large amount of information is available in dental records and the way these data can be analysed is presented in this paper. It appears that Cox's proportional hazard model is the appropriate way of demonstrating the influence of several factors on the survival rate. An example is provided of the results from a recent survival study of crowns in The Netherlands.

Types of patients with crowns in general dental practices.

Based on data from patient records of 9996 crowns constructed in forty general practices, it is discussed what crown types have been constructed in different patient categories. It was found that female 'crown patients' received on average more crowns than male patients. Hardly any difference was found between the average number of crowns the patients with or without reimbursement had received. In the younger patients (less than 21 years) more jacket crowns were constructed. The 21-30 year group received more full metal crowns, whereas the oldest group (greater than 51 years) had more metal-porcelain crowns. Sick-fund patients received more jacket crowns and metal-porcelain crowns on front teeth, while private patients received more full-metal crowns.

The metal post and composite core combination.

Restoring broken down non-vital teeth implies in general the provision of a post and core foundation. Many materials and techniques have been introduced for this purpose in recent years. In this article the advantages and disadvantages of the cast and the non-cast post and core are discussed. The problems involved with the application of the post and core are reviewed. An efficient procedure for restoring a broken down tooth with a prefabricated post in combination with a composite core is presented.

An evaluation of crowns and bridges in a general dental practice.

In this article the results are presented of an evaluation of crowns and bridges in a general practice. The study includes 601 solitary crowns, 213 crowns on bridge abutments and 103 crowns on RPD abutments. In total eighty-four bridges were examined. All these restorations were constructed during a period of 11.5 years. By means of the Kaplan-Meier method a prognosis is given of the life span of the different solitary crown-types over periods between 1 and 11 years. The total amount of failures and follow-up treatments on bridge and RPD abutments was very small. The authors also examined whether the bridges were constructed according Ante's law. A follow-up of this study in other Dutch general practices in combination with experimental clinical trials is under way.

Methodological aspects in clinical evaluation of cast restorations with colour slides.

In a methodological investigation colour slides were used for the clinical evaluation of crowns. Four criteria, described in a criteria list or recorded by means of reference slides, were used. In assessing the clinical characteristics of crowns to a certain extent colour slides turned out to be a useful instrument. Shortcomings of the method are discussed and improvements are suggested.