Torsten Mundt

The association of tooth loss with all-cause and circulatory mortality. Is there a benefit of replaced teeth? A systematic review and meta-analysis

We systematically reviewed whether the number of teeth is related to all-cause or circulatory mortality and whether replaced teeth are protective against all-cause or circulatory mortality. The search was based on the PubMed database. All cohort studies published in peer-reviewed journals were selected. Studies on periodontal disease and mortality were excluded if they did not provide information on the number of teeth. Risk estimates from studies with appropriate exposure definition, confounder adjustment and sample size were included in a meta-analysis. Three high-quality studies found a relationship between the number of teeth and circulatory mortality, whereas a moderate study did not. Two out of four moderate- to high-quality studies reported a relationship between the number of teeth and all-cause mortality. No study has investigated whether replaced teeth are protective against mortality. Therefore, denture use was taken as proxy. The methodological quality of studies on denture use and mortality was generally low to moderate. The findings of two moderate studies indicated an effect of prosthodontic replacements on all-cause mortality, which was supported in bias analysis. It is open whether competing risks of cause-specific death other than circulatory mortality reduce an effect of the number of teeth on all-cause mortality. An effect of denture use on circulatory mortality remains to be established, as well as whether the number of replaced teeth affects mortality. Specifying the role of potential pathways by which tooth loss-related mortality is mediated will possibly increase the value of dental treatment for general health.

Missing, unreplaced teeth and risk of all-cause and cardiovascular mortality

BACKGROUND A dentition of at least 20 teeth is associated with sufficient masticatory efficiency and is a stated health goal of the World Health Organisation. We examined whether subjects with missing, unreplaced teeth had an increased mortality risk. METHODS We used data prospectively collected from those participants in the population-based Study of Health in Pomerania who had fewer than 20 remaining teeth, resulting in a sample of 1803 participants with a median age of 64 years. Of those, 188 subjects had 9 or more unreplaced teeth. During a median follow-up period of 9.9 years, 362 subjects died, 128 of whom of cardiovascular causes. RESULTS We found that having 9 or more unreplaced teeth was related to all-cause mortality (rate ratio 1.53, 95% CI: 1.11-2.10; adjusted for variables according to causal diagrams: remaining teeth, age, sex, education, income, marital status, partnership, and oral health behaviour) and cardiovascular mortality (rate ratio 1.94, 95% CI: 1.15-3.25). When adjusting not only for the variables according to causal diagrams but also for smoking, alcohol consumption, physical activity, obesity, hypertension, diabetes, and dyslipidemia, the rate ratio was 1.43 (95% CI: 1.05-1.96) for all-cause mortality and 1.88 (95% CI: 1.10-3.21) for cardiovascular mortality. CONCLUSIONS A reduced, unrestored dentition is associated with increased mortality risk. Thus, clinicians and dietitians have a responsibility to consider individual chewing ability in nutritional recommendations.

Signs and symptoms of temporomandibular disorders and the incidence of tinnitus

In a cross-sectional analysis of data from the Study of Health in Pomerania (SHIP 0), temporomandibular disorders (TMD) were the strongest predictors for tinnitus beside headache. The aim of this study was to investigate whether signs and symptoms of TMD can be identified as risk factors for developing tinnitus. The SHIP 1 is a population-based 5-year longitudinal study intended to systematically describe the prevalence of and risk factors for diseases common in the population of Pomerania in northern Germany. A total of 3300 subjects (76% response) were reevaluated after 5 years for tinnitus and signs and symptoms of TMD using the same questionnaires and examination tools as baseline. To estimate the relative risk (RR) appropriately, a modified Poisson regression was used. After exclusion of prevalent cases with diagnosed tinnitus, 3134 subjects were analysed. Among the 191 exposed subjects with palpation pain in the temporomandibular joint (TMJ), 24 subjects (12·6%) received diagnosed tinnitus after 5 years, whereas among the 2643 unexposed subjects 142 subjects (5·8%) received tinnitus yielding a risk difference of 7·7% (95% confidence interval [CI]: 3·0%-12·5%) and a risk ratio of 2·60 (95% CI: 1·7-3·9). The risk ratio was 2·4 (95% CI: 1·6-3·7) after adjustment for gender, age, school education and frequent headache. Pain on palpation of the TMJ, however, did not worsen the prognosis for tinnitus in prevalent tinnitus cases (RR = 0·8, P = 0·288). Signs of TMD are a risk factor for the development of tinnitus.

The Randomized Shortened Dental Arch Study Tooth Loss

The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant.

Retrospective evaluation of temporary cemented, tooth and implant supported fixed partial dentures

INTRODUCTION The aim of this study was to examine the clinical performance of this method, and determine which temporary cement was the most appropriate. METHODS Dental fixtures (Tiolox implants GmbH, Germany) were implanted and crown and bridgework applied in a private practice between 1998 and 2003. Copings made of pure gold or titanium were permanently cemented onto the prepared teeth. The bridges were attached with either conventional temporary cements (Zinc oxide/ calcium hydroxide based) or acrylic/urethane cement (IMProv) both to the copings and to the implant abutments. Complications were evaluated by a retrospective review in January 2006. RESULTS A total of 47 patients (response: 81%) with 65 fixed partial dentures could be evaluated. Removal and re-attaching without damage of the dentures was undertaken for the following reasons: for follow-up examinations (n = 31), colour corrections (n = 15), cleaning of the dentures (n = 12), treatment of peri-implantitis (n = 2), repair following ceramic fractures (n = 5), implant failure (n = 1), tooth extractions (n = 2), root canal treatments (n = 2), occlusal corrections (n = 2), or in the case of abutment loosening (n = 4). Accidental detachments with conventional temporary cements occurred more frequently and more rapidly than with IMProv (15% versus 88.7% survival rate after four years). CONCLUSIONS This method for dental implant supported fixed partial dentures is successful and efficient.

The Randomized Shortened Dental Arch Study 5-year Maintenance

The scientific evidence concerning prosthodontic care for the shortened dental arch (SDA) is sparse. This randomized multicenter study aimed to compare two common treatment options: removable partial dental prostheses (RPDPs) for molar replacement vs. no replacement (SDA). One of the hypotheses was that the follow-up treatment differs between patients with RPDPs and patients with SDAs during the 5-year follow-up period. Two hundred and fifteen patients with complete molar loss in one jaw were included in the study. Molars were either replaced by RPDPs or not replaced according to the SDA concept. A mean number of 4.2 (RPDP) and 2.8 (SDA) treatments for biological or technical reasons occurred during the 5-year observation time per patient. Concerning the biological aspect, no significant differences between the groups could be shown, whereas treatment arising from technical reasons was significantly more frequent for the RPDP group. When the severity of treatment was analyzed, a change over time was evident. When, at baseline, only follow-up treatment with minimal effort is required, over time there is a continuous increase to moderate and extensive effort observed for both groups (Controlled-trials.com number ISRCTN97265367).

Gender-dependent associations between socioeconomic status and tooth loss in working age people in the Study of Health in Pomerania (SHIP), Germany.

OBJECTIVES Individual impact and the effect magnitude of socioeconomic key indicators (income, education and occupation) and of gender on oral health are ambiguous. In primary analyses of cross-sectional data among participants of the Study of Health in Pomerania (north-east Germany), women with low school education and low income were at highest risk for missing teeth, whereas being single was a risk indicator for missing teeth in men. Using the 5-year follow-up of this study, we aimed at verifying these findings and at investigating the gender-dependent impact of key socioeconomic indicators on tooth loss. METHODS The longitudinal data originate from 1971 subjects (1062 women) aged 25-59 enrolled from 1997 to 2001 and again from 2002 to 2006. The effects of marital status, household income, school education and occupational prestige for tooth loss were examined by gender using negative binomial regression analyses. RESULTS Low education and low income were moderately [relative risks (RR) between 1.6 and 2.0] associated with tooth loss among both women and men, whereas occupational prestige was not. After multiple imputations of missing data, less-educated women with lower income exhibited the highest risk of tooth loss [RR=3.1; 95% confidence interval (CI)=1.7-5.5 for <10 years of school education and the lowest income tertile] and tooth loss was more likely in single men (RR=1.5; 95% CI=1.0-2.2) than in single women (RR=0.9; 95% CI=0.6-1.3). CONCLUSIONS The primary cross-sectional results were partly confirmed. Socioeconomic factors help to explain differences in tooth loss, although the causal pathways are speculative. To improve dental health, the policies should target not only the individual, e.g. oral health promotion, but also an entire population by better education and higher wage employment.

Clinical response of edentulous people treated with mini dental implants in nine dental practices

OBJECTIVES To analyse implant survival, prosthetic aftercare and quality of life (QoL) after stabilisation of complete dentures with mini-implants. BACKGROUND Many edentulous patients refuse implant therapy due to the expenses and fear of surgery. Studies on minimally invasive and low-cost mini-implants remain rare. MATERIALS AND METHODS A total of 133 participating patients from nine private practices were evaluated via patient records, questionnaires and clinical examinations. Complications, maintenance, QoL questions and the German short version of the oral health impact profile (OHIP-G14) were analysed. RESULTS After 7 to 61 months, 15 of 336 maxillary implants and 11 of 402 mandibular implants had to be removed. In addition, four mandibular implants experienced fracture. The difference between the 4-year survival rates of 94.3% for the maxilla and 95.7% for the mandible was not statistically significant (p = 0.581). All original 144 overdentures remained functional. The prosthetic interventions were typically limited to repairs of acrylic base fractures (about one in five patients), changes of plastic O-rings and relining procedures. The participants showed OHIP-G14 scores (median = 2) that were comparable with those of patients with overdentures retained by conventional implants. CONCLUSIONS Mini-implant survival was similar to that of regular-diameter implants. Although some prosthetic aftercare was necessary, none of the overdentures had to be replaced. Prospective studies comparing conventional and mini-implants are warranted.

The randomized shortened dental arch study (RaSDA): design and protocol

BackgroundVarious treatment options for the prosthetic treatment of jaws where all molars are lost are under discussion. Besides the placement of implants, two main treatment types can be distinguished: replacement of the missing molars with removable dental prostheses and non-replacement of the molars, i.e. preservation of the shortened dental arch. Evidence is lacking regarding the long-term outcome and the clinical performance of these approaches. High treatment costs and the long time required for the treatment impede respective clinical trials.Methods/designThis 14-center randomized controlled investigator-initiated trial is ongoing. Last patient out will be in 2010. Patients over 35 years of age with all molars missing in one jaw and with at least both canines and one premolar left on each side were eligible. One group received a treatment with removable dental prostheses for molar replacement (treatment A). The other group received a treatment limited to the replacement of all missing anterior and premolar teeth using fixed bridges (treatment B). A pilot trial with 32 patients was carried out. Two hundred and fifteen patients were enrolled in the main trial where 109 patients were randomized for treatment A and 106 for treatment B. The primary outcome measure is further tooth loss during the 5-year follow-up. The secondary outcome measures encompassed clinical, technical and subjective variables. The study is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG WA 831/2-1, 2-2, 2-3, 2-4, 2-5).DiscussionThe particular value of this trial is the adaptation of common design components to the very specific features of complex dental prosthetic treatments. The pilot trial proved to be indispensable because it led to a number of adjustments in the study protocol that considerably improved the practicability. The expected results are of high clinical relevance and will show the efficacy of two common treatment approaches in terms of oral health. An array of secondary outcome measures will deliver valuable supplementary information. If the results can be implemented in the clinical practice, the daily dental care should strongly profit thereof.Trial registrationThe trial is registered at ClinicalTrials.gov under ISRCTN68590603 (pilot trial) and ISRCTN97265367 (main trial).

Bone stability around dental implants: Treatment related factors.

The bone bed around dental implants is influenced by implant and augmentation materials, as well as the insertion technique used. The primary influencing factors include the dental implant design, augmentation technique, treatment protocol, and surgical procedure. In addition to these treatment-related factors, in the literature, local and systemic factors have been found to be related to the bone stability around implants. Bone is a dynamic organ that optimises itself depending on the loading condition above it. Bone achieves this optimisation through the remodelling process. Several studies have confirmed the importance of the implant design and direction of the applied force on the implant system. Equally dispersed strains and stresses in the physiological range should be achieved to ensure the success of an implant treatment. If a patient wishes to accelerate the treatment time, different protocols can be chosen. However, each one must consider the amount and quality of the available local bone. Immediate implantation is only successful if the primary stability of the implant can be provided from residual bone in the socket after tooth extraction. Immediate loading demands high primary stability and, sometimes, the distribution of mastication forces by splinting or even by inserting additional implants to ensure their success. Augmentation materials with various properties have been developed in recent years. In particular, resorption time and stableness affect the usefulness in different situations. Hence, treatment protocols can optimise the time for simultaneous implant placements or optimise the follow-up time for implant placement.