Intervention for replacing missing teeth: Partially absent dentition-Evidence summary of Cochrane review.

Cochrane reviews are systematic reviews with meta analysis published by the Cochrane collaboration, in the Cochrane Database of Systematic Reviews (CDSR). These reviews provide the clinicians with the highest level of evidence as they use a highly structured and transparent systematic review model to address a specific research question. The management of partially absent dentition is routinely under taken by general dentist and Prosthodontist but clinical practice guidelines based on evidence to this common problem is yet to be summarized. This Cochrane systematic review aims to address the effect of different prosthesis for the treatment of partially absent dentition in the terms of, Long-term success, function, morbidity, and patient satisfaction. All randomized controlled trials were searched till March 18, 2011, based on the inclusion and exclusion criteria, 21 trials were included and 32 trials were excluded and, it was critically appraised using the Cochrane methodology for interventions. The summary of evidence from the study concludes that there is insufficient evidence to state the effectiveness of removable and fixed prosthesis in partially edentulous subjects in the following four outcomes. There were insufficient trials to perform a meta-analysis and sensitivity analysis. This evidence-based summary emphasizes and reinforces the need to reassess the quality of research currently pursued in our profession, to address the need to provide higher level of evidence for common conditions like partial edentulousness. The included studies are basically not from our population too, hence the urgency to address this critical issue.

INTRODUCTION

Treating partially edentulous patients with fixed or removable prosthesis is a routine procedure done for the past few decades by general dentist and prosthodontists. The two most common irreversible microbial diseases that result in tooth loss are the dental caries and the periodontal disease. Local risk factors like oral hygiene and diet vary among the individuals and have a great impact on the disease progress. The loss of teeth is a chronic problem and has a strong sociodemographic association. Currently, there is a lack of evidence to support specific and standardized treatment for various partially edentulous situation.[1] This Cochrane review covers the entire gambit of treatment for the partially edentulous condition from conventional fixed and removable prosthesis, implant prosthesis that are fixed or removable, and telescopic crown excluding the minimal preparation etched retained prosthesis. When multiple treatment options are available for treating partially edentulous situation, the selection of treatment for the patients must be based on evidence which reflects the needs and preferences of the patients.

There is no outcome-based clinical practice guidelines for partially edentulous patients from systematic review and meta-analysis published in the literature, so far. This Cochrane systematic review aims to provide informed clinical decision making for the patients and focus on the objective to address the following research question - “To assess the effect of different prosthesis for the treatment of partially absent dentition in the terms of the following outcomes: Long-term success, function, morbidity, and patient satisfaction.”[2] This question assumes significance as the incidence of tooth loss varies demographically and the risk factors for tooth loss has increased which may lead to increased partial edentulous condition.[3]

REVIEW METHODOLOGY

All Cochrane systematic review methodology for interventional studies follow the Cochrane handbook for systematic reviews of interventions.[4] The inclusion criteria for the studies considered in the review was randomized controlled trials treating patients with partial loss of teeth in one or both the jaws were included, and studies with surrogate end points were excluded. The type of intervention evaluated for removable partial denture prosthesis with tooth and tooth tissue supported comparing different design, material, and fabrication technique. In tooth supported fixed partial denture intervention compared different designs and materials. The treatment of shortened dental arch compared removable partial denture versus fixed partial denture and in implant supported prosthesis fixed partial denture versus tooth-implant supported fixed partial denture. The outcome measures recorded were: (1) Longevity/survival, complication and treatment failures as related to biological and mechanical complications, cumulative survival of the patient, time to re-treatment. (2) Functional/Physiological outcomes measuring prosthesis retention, satisfaction with functioning operator evaluation of the function. (3) Psychological measures involving patients satisfaction, social activity, quality of life using prevalidated questionnaire. (4) Economical impact of direct treatment, maintenance, and indirect treatment cost. The recorded data available at the following time points were taken into consideration, within 2 years, 2–5 years and more than 5 years after treatment.

The search was done in Medline, Embase and Central, Cochrane trial register till March 18, 2011 and was also hand searched for relevant publications. Two independent reviewers screened and selected the article and when in doubt it was arbitrated by a third person. The risk of bias assessment was done for within studies and across studies and stated from the extracted data. The measurement of treatment effect for dichotomous data was risk ratio and mean difference for continuous data at 95% confidence interval using random effect models. The treatment effect of split-mouth and parallel group was planned to combine using generic inverse variance.

Based on the inclusion and exclusion criteria 21 trials were included and 32 trials were excluded. The 21 included studies were divided into four categories removable prosthesis (5 studies) fixed prosthesis (13 studies) shortened dental arch (3 studies) and implant versus implant/tooth supported prosthesis (1 study). 18 trials compared within the prosthesis and only three compared one type of prosthesis with the other.

THE CRITICAL APPRAISAL OF 21 TRIALS FOR BEST EVIDENCE [TABLES 1–4]

The risk of bias summary states that the majority of the studies had the unclear risk of bias and five studies have a high risk of bias. There was insufficient trials to perform a meta-analysis. There was insufficient trials to do subgroup analysis and sensitivity analysis.

The review was not able to achieve its objective to assess the effect of different prosthesis for the treatment of partially absent dentition in the terms of the following outcomes: Long-term success, function, morbidity, and patient satisfaction due to few randomized control trial addressed comparison between prosthesis, most trial compared materials, design, method of fabrication or specific design, and significant heterogenicity was found between intervention and outcomes.

SUMMARY OF EVIDENCE

The summary of evidence from the study states that there is insufficient evidence to state the effectiveness of removable and fixed prosthesis in partially edentulous subjects in the following four outcomes. The intervention to treat shortened dental arch also has weak evidence to support one treatment method is better than the other. In the implant versus the implant/tooth fixed prosthesis, there is only one trial present providing weak evidence. This Cochrane review falls short of its objective due to lack of randomized controlled trial to address comparison between prosthesis, for particular partially edentulous conditions.

WHAT'S THE WAY AHEAD

To standardize the treatment of partially edentulous subjects, there is a need to design trials comparing different types of prosthesis used for partially dentate individuals. In most instances, a second or third study could not confirm the results of the first study to get pooled estimates. Very few studies have longer follow-ups than 10 years to fully estimate, comfort, satisfaction success, and survival rate of each prosthesis. The evidence-based practice involves a combination of best evidence, operators skill, and patients’ needs and preferences.[567] The currently available evidence are based on review of prospective cohort studies and retrospective studies which have a high risk of bias and confounding factors. Until more rigorous randomized trials are done with relevant interventions and outcomes, weak evidence from nonrandomized and analytical studies support evidence for treatment decisions tree which may not be the ideal approach in treating patients.

This evidence-based summary emphasizes and reinforces the need to reassess the quality of research currently pursued in our profession, to address the need to provide higher level of evidence for conditions like partial edentulousness. This Cochrane review has asked a very pertinent research question but the answers to this questions are very inconclusive due to the lack of high quality randomized controlled trials which needs to be addressed, to improve the quality of care for our patient.

Table 1

Intervention with removable prosthesis and available evidence

Table 2

Intervention with fixed prosthesis and available evidence

Table 3

Intervention for shortened dental arches and available evidence

Table 4

Intervention with implant versus tooth/implant supported prosthesis and available evidence