Forty-five-year tooth survival probabilities among men in Oslo, Norway

Survival of root filled teeth in general dentistry in a Swedish county: a 6-year follow-up study

OBJECTIVE

The purpose of the present study was to investigate the survival rate of root filled teeth in general dentistry in a Swedish county and to identify risk predictors with a significant influence on the survival rate.

MATERIALS AND METHODS

This is a retrospective 6-year follow-up study on 1642 recall patients with 1720 teeth root filled in general dentistry in the Public Dental Service in the county of Stockholm, Sweden. Background variables were collected from the database at baseline as potential predictors of tooth loss. The outcome variables were extraction during the 6-year follow-up period and the reason for the extraction. Stepwise Cox regression analysis was adopted in order to investigate the influence of the potential risk predictors on the risk for tooth extraction.

RESULTS

Nine percent of the root filled teeth were lost after 6 years. The most frequent reason for tooth loss was fracture and/or cracks (58%). The survival rate of the root filled teeth increased significantly for younger patients, root filled teeth with metal crowns (96%) and high quality of the root filling (93%). The survival rate differed significantly between tooth groups with the lowest survival for molars (83%). Composite fillings were significantly associated with lower quality of the root fillings.

CONCLUSIONS

Ninety-one percent of the root filled teeth survived after 6 years. The survival rate was significantly higher for teeth with root-fillings of high quality and metal crowns as well as for root filled teeth in younger patients. The lowest survival rate was found for molars.

Applying Modern Survival Analysis Methods to Longitudinal Dental Caries Studies

Before the 1960s, tooth-specific caries risk was reported to be highest at 2 to 4 years after eruption. We studied the tooth-specific caries risk in three contemporary age cohorts in Finland. All together, 4072 boys and girls were followed annually from age 6 to age 18+ years in three age cohorts born in the 1960s, 1970s, and 1980s. We used a survival model and Bayesian inferential methods in the statistical analyses to establish the secular changes during this period. The analysis was based on the caries risk in individual teeth as a function of tooth age instead of summary measures, such as DMFS values. Our first finding was a marked overall decrease of caries. Moreover, analyses of the 1960 and 1970 cohorts revealed that the risk in molar teeth was highest immediately after eruption; in the youngest cohort, however, the risks of individual teeth were so low that no such dependencies on tooth age could be established.

A comparison of antemortem tooth loss in human hunter-gatherers and non-human catarrhines: implications for the identification of behavioral evolution in the human fossil record

Middle and Late Pleistocene fossil hominin specimens with severe antemortem tooth loss are often regarded as evidence for the precocious evolution of human-like behaviors, such as conspecific care or cooking, in ancient hominin species. The goal of this project was to ask whether the theoretical association between antemortem tooth loss and uniquely human behaviors is supported empirically in a large skeletal sample of human hunter-gatherers, chimpanzees, orangutans, and baboons. Binomial regression modeling in a Bayesian framework allows for the investigation of the effects of tooth class, genus, age, and sex on the likelihood of tooth loss. The results strongly suggest that modern humans experience more antemortem tooth loss than non-human primates and identify age in years as an important predictor. Once age is accounted for, the difference between the humans and the closest non-human genus (chimpanzees) is less pronounced; humans are still more likely on average to experience antemortem tooth loss though 95% uncertainty envelopes around the average prediction for each genus show some overlap. These analyses support theoretical links between antemortem tooth loss and modern human characteristics; humans' significantly longer life history and a positive correlation between age and antemortem tooth loss explain, in part, the reason why humans are more likely to experience tooth loss than non-human primates, but the results do not exclude behavioral differences as a contributing factor.

Oral hygiene behaviour change during the nonsurgical periodontal treatment phase

The purpose of the present study was to investigate the frequency of smoking cessation and the use of proximal tooth cleaning routines after a nonsurgical periodontal treatment phase in a Specialist clinic of Periodontology and to evaluate if these behaviour changes had any influence on the periodontal healing results. The investigation was conducted as a retrospective longitudinal study on a randomly selected population of 100 patients referred for periodontal treatment. The variables were registered from the dental records and the radiographs. Forty-six individuals declared that they were smokers at baseline and one individual of those quitted smoking during the nonsurgical treatment period. The percentage of individuals who performed proximal tooth cleaning daily was significantly increased from 56% to 72% during the treatment period. The patients practising proximal tooth cleaning daily had significantly lower Plaque index before as well as after the nonsurgical periodontal treatment phase compared to those without the routine. The subjects who did not perform tooth cleaning daily before the treatment and who did not introduce this routine had significantly deeper periodontal pockets compared to those who performed inter-dental cleaning daily before treatment or who had adopted the routine during the treatment phase. However, there were no significant differences according to number of deepened periodontal pockets after nonsurgical treatment irrespective of proximal cleaning routines. In the future, motivational interviewing may be a more effective method to achieve a behaviour change if an extended education of dental hygienists within this area will be implemented.

Association of endodontic involvement with tooth loss in the Veterans Affairs Dental Longitudinal Study

INTRODUCTION

The effect of endodontic involvement on tooth loss has not been quantified, so the present study aimed to assess this relationship after controlling for other relevant risk factors for tooth loss.

METHODS

We analyzed data from 791 participants (18,798 teeth) in the Veterans Affairs Dental Longitudinal Study. Potential tooth-level and person-level covariates were fitted into marginal proportional hazards models, including both apical radiolucencies (AR) and root canal therapy (RCT) status as time-dependent variables. Survival curves were plotted for teeth according to their AR and RCT status.

RESULTS

Both current AR and RCT status were associated with increased risk of tooth loss (P < .01), after controlling for baseline levels of periodontal disease, caries, tooth type, number of proximal contacts, number of teeth, age, education, and smoking history. Root canal filled (RCF) teeth seemed to have better survival than non-RCF teeth among teeth with AR but worse survival than non-RCF teeth among teeth without AR.

CONCLUSIONS

Endodontic involvement was associated with tooth loss, controlling for other potential risk factors. Additional prospective studies are needed to provide better evidence as to the impact of endodontic involvement on tooth loss.

Tooth loss and associated factors in long-term institutionalised elderly patients

OBJECTIVE

To compare partial and total tooth loss in dependent institutionalised elderly patients and identify any associated factors.

BACKGROUND

A poor oral health status, together with a reduction of autonomy can seriously affect the general health and increase the risk of death in elderly people. Those with total tooth loss and in need of assistance are the most at risk.

MATERIALS AND METHODS

In 2004, a cross-sectional study of 321 elderly patients was conducted in long-term hospital services provided in Montpellier, France. Socio-demographic, behavioural, medical and oral health information was recorded for each patient. Multivariate logistic regression models were performed to test the relationship between those covariates and partial or total tooth loss. Pearson chi-squared tests were used for bivariate analyses.

RESULTS

The proportion of edentulousness was 26.9%; among these12.6% had no dentures. The factors significantly associated with edentulism were: an age 'older than 87 years' [odds ratio (OR) = 9.4], the presence of a nephropathy (OR = 6.8), and inadequate oral hygiene (OR = 0.1). The factors most significantly associated with partial tooth loss (at least 21 missing teeth) were 'cancerous disease' (OR = 9.9), the presence of a nephropathy (OR = 5.6) and the presence of a neurological disease (OR = 4.1). The factors significantly related to dentate status (20 or more natural teeth retained) were 'hypertension treatment' (OR = 2.4), and 'cortisone treatment' (OR = 0.2).

CONCLUSION

General health problems as well as a poor oral condition were significant risk indicators for tooth loss among the long-term institutionalised elderly. This suggests that the number of remaining teeth has a strong effect on oral health-related quality of life.

Social inequality in tooth extraction in a Brazilian insured working population

OBJECTIVES

Given the scant evidence of the socioeconomic gradient in tooth loss incidence, the purpose of this study was to compare the odds of individuals of distinct social strata being subjected to tooth extraction.

METHODS

We undertook a case-control study at the head office of a large Brazilian company whose employees had access to dental care through the company's dental insurance.

RESULTS

During 2 years of observation, 264 teeth were extracted and the distribution of such extractions was rather unequal. A strong suggestion of a social gradient was noted and the odds of tooth extraction occurring per social strata, adjusted by age and gender, were five times higher in employees pertaining to the lowest social stratum, when compared with those at the highest.

CONCLUSIONS

We concluded that lower social strata were strongly associated with increased risk of having teeth extracted. Dental insurance was not able to equalize the chances of tooth extraction among different social strata, in a population of employed adults.

Trends in prosthodontics

Prosthodontics is concerned with the impact of tooth or tissue damage and partial or complete loss of teeth on oral function in its broadest sense. It deals with this largely through prosthetic replacement. The discipline occupies a major portion of a dental school curriculum, and dental practitioners usually devote much of their practice to prosthodontic services. With the rapid improvement in oral health and the reduction of edentulism in many countries, increasing numbers of people are retaining more teeth later in life.Gradually,the main focus in prosthodontics has shifted from removable dentures to fixed prostheses, while implant-supported restorations have attracted intense interest in the dental community. Another factor increasingly influencing prosthodontic practice is patients' awareness of newer technologies in aesthetic dentistry. Because prosthodontic interventions as well as maintenance and repair are by nature costly, the global development in the field manifests fundamental inequalities in the levels of service that patients can access. Diminishing resources for health care in general challenges educators and practitioners of prosthodontics alike. This review is an attempt to describe the recent developments in prosthodontics and its therapeutic areas, and the impact such developments may have on the theory and practice of the discipline.

A systematic review of the effectiveness of self-performed mechanical plaque removal in adults with gingivitis using a manual toothbrush

OBJECTIVE

To assess the effectiveness of self-performed mechanical plaque removal in adults with gingivitis using a manual toothbrush with respect to the level of plaque and gingivitis in controlled studies of at least 6 months duration. SEARCH: Medline-PubMed up to and including September 2004.

RESULTS

Out of 3223 titles and abstracts, 33 trials were found for data extraction. A meta-analysis was conducted of studies (n=9) in which, for the manual toothbrush group at baseline, only a professional prophylaxis provided. The weighted mean differences (WMD) between baseline and end-trial for the Quigley & Hein plaque index was 0.28 and 0.21 for the Gingival Index (p<0.05). Eight studies provided both a professional OHI and prophylaxis at baseline. The WMD for the Silness & Löe Plaque Index was 0.10 (ns). The WMD of the proportion of bleeding sites was 5.84% (p<0.05).

CONCLUSION

In adults with gingivitis the quality of self-performed mechanical plaque removal is not sufficiently effective and should be improved. Based on studies > or = 6 months of duration, it appears that a single oral hygiene instruction, describing the use of a mechanical toothbrush, in addition to a single professional 'oral prophylaxis' provided at baseline, had a significant, albeit small, positive effect on the reduction of gingivitis.

Root Canal Filled Versus Non-Root Canal Filled Teeth: A Retrospective Comparison of Survival Times

OBJECTIVE

This matched cohort study used data from a large dental HMO in the Pacific Northwest to evaluate the degree to which pulpal involvement and subsequent endodontic therapy affects tooth survival. Root canal filled (RCF) teeth were used as an indicator of pulpal involvement. Our hypothesis was that RCF teeth would be extracted sooner than non-RCF teeth matched within subjects, controlling for tooth-level variables of interest.

METHODS

The HMO's treatment databases and a subsequent chart audit were used to identify 202 eligible subjects, each of whom had one tooth endodontically treated in 1987-88 and a similar contralateral tooth that was non-RCF at that time. Both teeth were followed from the endodontic access date through the extraction date, the endodontic access date (for initially non-RCF teeth), or 12/31/94, whichever was earliest. Time-to-event analyses were carried out, with Kaplan-Meier curves generated and multivariable marginal proportional hazards regression models fitted to describe the effect of RCF status on tooth survival. All statistical analyses accounted for the complex sampling strategy used in generating the dataset.

RESULTS

Teeth were followed for up to eight (median = 6.7) years. RCF teeth had substantially worse survival than their non-RCF counterparts (p < 0.001), with a greater effect of RCF status evident among molars than non-molars. Adjusted hazard ratios (95% confidence intervals) for loss of RCF versus non-RCF molars and non-molars were 7.4 (3.2-15.1) and 1.8 (0.7-4.6), respectively.

CONCLUSION

Though endodontic therapy can prolong tooth survival, pulpal involvement still may hasten tooth loss, underscoring the importance of caries prevention and prompt restorative care.

The clinical course of chronic periodontitis. IV. Gingival inflammation as a risk factor in tooth mortality

AIM

The purpose of this study was to assess the long-term influence of gingival inflammation on tooth loss.

MATERIAL AND METHODS

The data originated from a 26-year longitudinal study of Norwegian males, who practiced adequate daily oral home care and received "state-of-the-art" dental care. The initial examination in 1969 included 565 individuals aged between 16 and 34 years. Subsequent examinations took place in 1971, 1973, 1975, 1981, 1988 and 1995. Thus, the study covers the age range of 16-59 years. The teeth were divided into three tooth groups (I-III) reflecting the history of inflammation of the surrounding gingiva (gingival index (GI) scores) over 26 years: (I) teeth with surrounding gingival units scoring a minimum of one site with GI=0 and a maximum of three sites with GI=1, (II) teeth with surrounding gingival units scoring a minimum of one site with GI=1 and a maximum of three sites with GI=2 over the observation periods and (III) teeth with surrounding gingival units always scoring a minimum of GI=2 (bleeding on probing) at all sites over the observation period.

RESULTS

At baseline (1969), out of possible 15,820 teeth (565 x 28), 15,383 teeth were present. Four hundred and thirty-seven teeth had already been missing for unknown reasons. By 1995, 13,159 teeth were reexamined, i.e. over the 26-year observation period only 126 (0.95%) teeth were lost. Only 16 (0.28%) of 5793 teeth belonging to GI-Severity Group I were lost. In the GI-Severity Group II, however, 78 (2.28%) out of 3348 teeth were lost, and 13 (11.21%) of 103 teeth with GI-Severity Group III were lost. Teeth with GI-Severity Group III yielded an odds ratio for tooth loss that was 46 times higher than that of teeth with GI-Severity Group I, and five times higher than that of teeth with GI-Severity Group II over 26 years. Furthermore, teeth with the GI-Severity Group II had a nine times higher risk for tooth loss than teeth with the GI-Severity Group I. The GI-Severity Group I retained 99.5% of the teeth after a tooth age of 51 years. The GI-Severity Group II retained 93.8% of the teeth after a tooth age of 50 years. However, in the GI-Severity Group III, 63.4% of the teeth were retained for a tooth age of 47 years.

CONCLUSIONS

Teeth surrounded with inflammation-free gingival tissues were maintained for a tooth age of 51 years, while teeth consistently surrounded with inflamed gingivae yielded a 46-times higher risk to be lost. Only two-thirds of such teeth were maintained throughout the 26-year observation period. This documents the role of gingival inflammation as a risk factor for future tooth loss.

Using survival methodologies in demonstrating caries efficacy

Exploiting recent advances in statistical methods, particularly for correlated intra-subject data, could increase the efficiency of caries clinical trials. Methods of analysis using the tooth surface as the unit should be investigated. Whole-mouth measures such as the DMFS increment ignore the variation in the number of surfaces at risk between subjects and within a subject over time. The use of "survival time" for each surface as the outcome measure--i.e., the time from the start of the trial to when a surface is recorded as decayed or filled--is proposed. Data from caries clinical trials could be described as clustered survival data, where clustering of tooth surfaces exists such that survival times within the same cluster or subject are correlated. Advances in the analysis of clustered survival data, such as the use of marginal models with robust variance estimators, have recently been exploited in the analysis of caries clinical trials. The analysis produced results similar to those achieved by conventional DMFS-based analysis. The results using survival analysis are easily interpreted-for example, the median survival time of tooth surfaces in female subjects using a toothpaste with a higher level of fluoride (1500 ppm F) is 1.07 times the median survival time of surfaces in female subjects using toothpaste with less fluoride (1000 ppm F). Further research is required to investigate if survival analysis is a more sensitive method of analysis, i.e., whether causative factors can be identified with fewer subjects than with the conventional method of analysis.

Incidence and predictors of self-reported tooth loss in a representative sample of Norwegian adults

OBJECTIVES

The purpose of this study was to determine the self-reported 12-month incidence of tooth loss among Norwegian adults and to assess the association between tooth loss and some predictor variables.

METHODS

Of a two-stage nation-wide, representative random sample (n = 3958), information was obtained from 2682 subjects aged 20-79 years and the response rate was 68%. Telephone or face-to-face interviews by interviewers employed by the Central Bureau of Statistics (CBS) of Norway. Information was collected about demographic characteristics, the number of natural teeth present, the number of teeth lost during the last 12 months, and belief in keeping natural teeth for life. The present analyses are based on 2520 persons 20-79 years of age.

RESULTS

The proportion of respondents who reported losing one or more teeth was 6.45% (95% confidence limits (CL) = 5.49, 7.41). The participants who reported extractions had lost on average 1.54 (range 1-9) teeth. Multiple logistic regression analysis revealed a borderline significant effect of the level of education (OR = 0.68, 95% CL = 0.46, 1.00), i.e. the odds of losing one or more teeth during the last 12 months were lower among persons with more than 12 years of education than among persons with less education. The explained variance was 1.9%.

CONCLUSION

The annual incidence rate of tooth loss among Norwegian adults was found to lie within the range reported from other industrialized countries. After controlling for socio-demographic variables and the number of teeth present, the only borderline significant predictor of the incidence of tooth loss was the level of education.

Relationship between crown placement and the survival of endodontically treated teeth

STATEMENT OF PROBLEM

Crowns have been considered the restoration of choice for endodontically treated teeth, but their selection has been based primarily on anecdotal evidence.

PURPOSE

This study tested the hypothesis that crown placement (coronal coverage) is associated with improved survival of endodontically treated teeth when preaccess, endodontic, and restorative factors are controlled.

MATERIAL AND METHODS

A University of Iowa College of Dentistry treatment database was used to identify permanent teeth that had undergone initial obturation between July 1, 1985, and December 31, 1987. Study patients were restricted to persons with at least 1 dental visit in each 2-year interval from 1985 to 1996; a simple random sample of 280 patients (n = 400 teeth) was selected. Dental charts, radiographs, and computerized databases were examined to ascertain variables of interest and to verify study inclusion criteria. Kaplan-Meier survival estimates were generated for the 203 teeth that satisfied study inclusion criteria. Multivariate Cox proportional hazards regression models were developed, with standard errors adjusted to account for clustering of teeth within patients.

RESULTS

When tooth type and radiographic evidence of caries at access were controlled, the final Cox model showed that endodontically treated teeth not crowned after obturation were lost at a 6.0 times greater rate than teeth crowned after obturation (95% confidence interval: 3.2 to 11.3).

CONCLUSION

Within the limitations of this study, a strong association between crown placement and the survival of endodontically treated teeth was observed. These results may impact treatment planning if long-term tooth retention is the primary goal.

Relationship between number of proximal contacts and survival of root canal treated teeth

AIM

The present study tested the hypothesis that having two proximal contacts (PCs) at access is associated with improved survival of root canal treated (RCT) teeth, controlling for important presenting conditions, endodontic variables and restorative factors.

METHODOLOGY

A treatment database at the University of Iowa College of Dentistry was used to identify permanent teeth undergoing obturation between 1 July 1985 and 31 December 1987. The list was restricted to teeth of patients with at least one dental visit in each two-year interval from 1985 to 1996, and a simple random sample of 280 patients (n = 400 teeth) was selected. Dental charts, radiographs, and computerized databases were examined to ascertain variables of interest and to verify study inclusion criteria. Kaplan-Meier survival estimates were generated for the 221 teeth satisfying study inclusion criteria. Multivariate Cox models were developed, with standard errors adjusted to account for clustering of teeth within patients.

RESULTS

The final Cox model showed that teeth with < or =1 PC at access were lost at a rate three times that of teeth with 2 PCs (hazard ratio = 3.1; 95% confidence interval = 1.9-5.1), controlling for tooth type, presence of radiographic caries at access, and presence of a crown before or after obturation.

CONCLUSIONS

Because RCT teeth with two PCs at access experienced substantially better survival than teeth with fewer than two PCs, the influence of PCs on prognosis should be recognized during treatment planning. Future research should employ prospective study designs, capture additional variables, and provide data to support endodontic treatment decisions.

Tooth loss in the very old: 13-15-year incidence among elderly Iowans

OBJECTIVES

Very few studies have reported tooth loss incidence over a period of 10 years or more, and fewer have reported tooth loss occurrence in subjects aged 80 and older, so that the long-term pattern of tooth loss in the very old is largely unknown. This study assessed 13-15-year tooth loss incidence among a cohort of Iowans, aged 65 and older at baseline.

METHODS

Oral examinations were conducted on 520 subjects beginning in 1983, and periodically until 1988, with another round of examinations conducted on surviving members of the initial cohort during 1996-98.

RESULTS

Of the 73 remaining subjects, 45 subjects lost a total of 153 teeth during the period (mean=2.1 teeth lost), with a maximum of 17 teeth lost. Molars were the most commonly lost teeth, while canines and maxillary incisors were the least commonly lost. Bivariate analyses found that tooth loss was associated with untreated decay at baseline and level of periodontal attachment loss at earlier examinations. Logistic regression identified only greater severity of attachment loss as a significant risk factor for tooth loss (Adjusted odds ratio=2.4, P=0.006). The impact of tooth loss on subjects' lives was assessed using OHIP and other questions. The occurrence of tooth loss over the study period had little impact, but the number of remaining teeth significantly impacted subjects' ability to eat or chew food, swallow, or their willingness to smile.

CONCLUSIONS

These results suggest that tooth loss continues in the very old, that periodontal attachment loss is associated with tooth loss in this age group, and that loss of teeth over one's lifetime does affect certain quality-of-life measures.

Non-surgical periodontal therapy and tooth loss. A cohort study

BACKGROUND

No reliable evidence is available regarding the effect of periodontal therapy on major disease endpoints such as tooth loss, edentulism, or quality of life. The primary objective of this study was to assess the association between tooth loss and the non-surgical periodontal treatment history of 1,021 members of the Kaiser Permanente Dental Care Program.

METHODS

Tooth loss rates were estimated using Poisson regression models, adjusting for some of the potentially confounding variables such as initial disease severity and extent.

RESULTS

Continuous non-surgical therapy (one or more non-surgical procedures performed during 3 successive years), as opposed to no therapy during such a 3-year period, reduced the subsequent tooth mortality rate by 58% (relative rate, 0.42; 95% confidence interval, 0.29-0.61). Intermittent non-surgical therapy reduced the tooth mortality rate by 48% (RR = 0.52; 95% confidence interval, 0.34-0.80). As the number of non-surgical procedures increased, tooth loss rates decreased.

CONCLUSIONS

These findings suggest that non-surgical periodontal therapy may be associated with a substantial reduction in tooth mortality. Different study designs and populations are needed to confirm these findings.