EFFECT OF SPLINTING AND NON SPLINTING OF IMPRESSION TRANSFER DURING IMPRESSION MAKING ON THE FIT OF MULTI-IMPLANT SUPPORTED FIXED FULL ARCH FRAMEWORKS

Zakaria A 1 , Kaddah AF 2 , Fayyad AE 3 and Al-quitaiby AY 4 . 1. Zakaria A: Ph.D researcher, removable prothodontic department, Faculty of dentistry, Cairo University. 2. Kaddah AF: Professor of removable prothodontic, Faculty of dentistry, Cairo University. 3. Fayyad AE: Associate Professor of removable prothodontic, Faculty of dentistry, Cairo University. 4. Al-quitaiby AY: Ph.D removable prothodontic, Faculty of dentistry, Cairo University. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


Selection of the Studies:-
Papers were included if the following criteria were fulfilled: dental publications in English, randomized controlled trials, a minimum sample size of 10 patients. The Pubmed search resulted in 196 articles, Cochrane search resulted in 88 articles in addition to 2 record identified from other sources. After the initial screening, 16 publications were selected for additional evaluation of the full-text version for being directly related with the aim of the present study. Finally, 3 RCTs fulfilled were included and 13 articles were excluded. Finally a total of 3 publications were selected for data analysis.

Data Collection and Analyses:-
Two reviewers (Zakaria A and Fayyad AE) evaluated the relevance of the studies by a first selection based on the title and abstract. Disagreement about whether a study should be included for full inspection was resolved by a consensus discussion. The final full texts were included only after a mutual agreement between the two reviewers and any disagreements were resolved by mutual discussion; if not a third reviewer (Kaddah AF) was consulted.
Data Extraction and Management:-Data were extracted independently by the reviewers whose were reciprocally blinded to each other"s extraction. The name of author(s), publication year, participants, intervention type, no. of implants and position, outcome measures/variables and outcomes of studies were extracted (table 1).

The Quality Assessment:-
Assessing risk of bias of individual studies was accomplished according to the Cochrane Collaboration tool for assessing the risk of bias (Table 8.5.a in the Cochrane Handbook for Systematic Reviews of Interventions). The domains that were assessed for each included study are: random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting and risk of other bias.
Risk of bias assessment was carried out independently by two reviewers. After the assessment each study a decision was made for each study describing it as "Low risk of bias" if all domains were at low risk of bias, "Unclear risk of bias" if there was unclear risk of bias of at least one domain, and "High risk of bias" if at least one domain was scored as being at a high risk of bias (table 2).

Statistical Analyses Measures of Treatment Effect:-
The estimate of effect of an intervention was expressed as Risk Differences (RDs) together with 95% confidence intervals (CIs) in regard to dichotomous outcomes. Mean Differences (MDs) and standard deviations were used to summarise the data for each group with 95% CIs in regard to continuous outcomes.

Unit of Analysis:-
The framework or verification jig was considered as statistical unit.

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Missing Data:-The missing relevant information of the included trials was requested from the corresponding authors via email and reminder emails were sent if no responses.

Assessment of Heterogeneity:-
The significance of any variations in the estimates of the treatment effects from the different trials was to be assessed by means of Cochran"s test for heterogeneity, and heterogeneity would have been considered significant if P value < 0.1. Heterogeneity between the studies was assessed using the I-squared statistic (I2-statistic), which describes the variation percentage due to heterogeneity rather than chance (I2 over 50% was considered as moderate to high heterogeneity).

Results:-
The search conducted in two databases on November 2017 found 196 studies on Medline (PubMed), 88 on Cochrane. Of these, 14 articles were selected for review. An additional 2 studies were added by manual search, bringing the total up to 16 studies. After filteration by title and abstract only 3 studies were selected for the review. The selection process is summarized in a flow diagram (Figure 1). The following variables were extracted from these studies (Table 1): author, year, type of implant, total implant number, impression number, impression level, splinting methods, splinting material, impression material, type of stone, method of framework fabrication, framework level, number of frameworks, fitting test, number of subjects per study, number of subjects per group, number of frameworks per group, number of fit and miss-fit frameworks.      15-16-17-18 Other studies in agreement with the results of this review have stated that both impression techniques provide comparable results. 19-20-21 Number of studies clinically evaluated accuracy of splinted and non-splinted implant impression is low compared with the in-vitro studies in the same field so that, it is important to gather the clinical trials as there is many clinical factors that affect accuracy of implant impressions that can"t be simulated in the in-vitro studies such as functional elastic deformation of the jaws during different mandibular movements. (13)(14) The included studies used common and applicable coping splinting techniques which are frequently used in practice.