MINI-IMPLANT- VERSUS CONVENTIONAL IMPLANT-RETAINED MANDIBULAR OVERDENTURE IN COMPLETELY EDENTULOUS PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Marwa Hassan Mostafa 1,2 , Ali Abdulghani AlSourori 2,3 , Amal Fathy Kaddah 4 and Ahmed Emad Fayyed 5 . 1. Assistant Researcher, Department Of Fixed And Removable Prosthodontics, National Research Center, Egypt 2. PhD Candidate Prosthodontics, Faculty of Oral and Dental Medicine Cairo University, Egypt. 3. Lecturer of Prosthodontics, Faculty of Dentistry, Ibb University, Yemen. 4. Head of Department Of Prosthodontics, Faculty of Oral and Dental Medicine Cairo University, Egypt. 5. Assistant Professor at Faculty of Oral and Dental Medicine Cairo University, Egypt. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


ISSN: 2320-5407
Int. J. Adv. Res. 5 (11), 992-1002 993 (Burns 2000) stated that utilizing dental implants to retain over-denture will provide excellent benefits than conventional denture essentially due to bone preservation around implant and inhibition of further bone loss. (Doundoulakis et al 2003) Stated that implant supported over denture have a higher success rate furthermore it promote patient satisfaction, denture retention and stability and they concluded that implant supported over-denture should be the first choice when treating completely edentulous patients.
(The McGill consensus) instituted that mandibular over dentures retained by two implants in the inter foramina area should be the first choice standard of care for the edentulous patient. (Feine et al 2002) Overdentures supported by conventional implants display good long-term results however; some limitations are present such as: cost  difficultly with the implant insertion in reduced buccolingual dimensions of bone without the need for bone-grafting procedures ( Therefore, the goal of this systematic review was to verify the feasibility of using mini implants to retain overdentures. The assumptions of this study were: (1) There is no difference regarding the survival rates between mini implants retaining overdenture prosthesis compared with standard implants; (2) Mini implants do not affect marginal bone loss, satisfaction, or quality of life.

Materials and Methods:-
This systematic review accomplished according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). (Moher et al 2009) Research Question:-For mandibular implant retained over denture patients will the use of mini implants retained over denture result in different satisfaction, quality of life, implant loss and prosthetic maintenance when compared with standard implant retained over denture?
PICO Format:-P -Mandibular retained over dentures Imini implants C-Standard implants O-Patient satisfaction, quality of life, Implant survival rate, and prosthetic maintenance.
A prior protocol for This systematic review was created and registered in at PROSPERO International prospective register of systematic reviews (PROSPERO: CRD42017068623).

Search Strategy:-
The Pub Med and Cochrane databases will be searched for published articles until March 15-2017. Regarding language we plan to restrict research to English language only. In addition, a manual search was performed from references and from the journals: Clinical implant dentistry and related research, Clinical Oral Implants Research, Journal of prosthodontics and Journal of prosthetic dentistry The following search terms were performed:mandibular overdentures OR mandibular overdenture OR mandibular over-dentures OR mandibular over-denture OR mandibular overlay dentures OR mandibular overlay denture OR mandibular overlay prosthesis OR mandibular overlay prostheses OR lower overdentures OR lower overdenture OR lower overdentures OR lower overlay dentures OR lower overlay prosthesis OR lower over-denture OR lower over_denture OR lower over_dentures OR lower over-dentures OR mandibular stabilized overdenture OR mandibular anchored overdenture OR mandibular assisted overdenture OR mandibular retained overdentures AND (((((((((((mini dental implant) OR mini dental implants) OR mini implants) OR mini implant) OR single piece dental implant) OR single piece dental implants) OR one piece dental implant) OR narrow dental implants) OR little dental implants) OR small dental implant) OR minute dental implant) OR tiny dental implant AND (((((((((((conventional dental implant) OR conventional dental implants) OR standard dental implant) OR standard dental implants) OR regular dental implant) OR normal dental implant) OR normal dental implants) OR typical dental implant) OR average dental implant) OR usual dental implants) OR conventional implant) OR standard implant Disagreement between reviewers (MH, AA,) was resolved by the observer (AK). The kappa agreement was calculated.

Quality and Risk of Bias Assessment:-
The Quality assessment of included studies was performed using the Cochrane Collaboration tool for assessing the risk of bias(Higgins et al.,2011 ,which covers: sequence generation, allocation concealment, blinding, incomplete outcome data (e.g. dropouts and withdrawals) and selective outcome reporting. For each domain in the tool, we will describe the procedures undertaken for each study, including verbatim quotes. A judgment as to the possible risk of bias on each of the six domains will be made from the extracted information, rated as 'high risk' or 'low risk'.

Data Extraction and Analysis:-
All reviewers were extracted data independently from each eligible study. Data abstracted were including and all reported patient-important outcomes. Therefore, it was decided to tabulate the data where appropriate and report the findings in a description manner. The following information was required: demographic information (study ID, number of patients) methodology (immediate loading, conventional loading), intervention details, (type of implants, type of attachments, period of follow up,) and outcomes on patients' satisfaction, quality of life, survival rate and prosthetic maintenances. Reviewers were resolve disagreements by discussion.
Meta-analyses were performed from studies on survival rates (odds ratio with random effects model). The reviewers (MH, AA,) extracted relevant information from the selected articles and entered it into a Microsoft Excel worksheet independently from each other. Due to the heterogeneity of outcome variables, and reporting, no meta-analysis was performed.

Identification of Studies:-
Searches of the databases resulted in 124articles (Fig. 1) of these, 75 articles were excluded, as it was clear from the title and abstract that they did not fulfill the selection criteria. For the remaining 49 articles, 6 articles were duplicated, the remaining 43 full articles were obtained and following analysis of these, five potentially relevant studies were identified. 38 publications were excluded for the following reasons: case reports, non RCT, retrospective, cohort, studies not comparing mini implant with conventional implant. Therefore, 5 studies were included in the present study ( Table 1).

Discussion:-
This systematic review was done to decide if there is an actual variance between mini dental implant and conventional dental implant over-dentures in the tem of patient satisfaction and implant loss in addition to the peri implantitis complication that expressed as marginal bone loss. Patient's satisfaction is considered the most important patient related outcomes in the evidence based dentistry however there is no standard format to evaluate this outcomes. Visual analogue scale (VAS) is considered the most reliable scale to assess the patient sat isfaction. Implant loss was reported by the number of implant lost during the follow up period. Peri-implantitis is an advanced damage of peri-implant tissue and can be assessed by gingival index, plaque index, pocket depth in addition to clinical attachment loss and marginal bone loss (MBL). But, in this review we choice the marginal bone loss as a parameter for peri-implantitis since it is the most essential indicator and most of trial basically evaluate periimplantitis via MBL measurement.
Comparing earlier systematic reviews in the similar subject which contain RCTs, prospective and retrospective studies, we attempt in this systematic review to focus on the mandibular implant retained over-denture to reach strong evidence by including only a randomized clinical trials because this type of studies is considered as a high quality studies in evidence based dentistry. Moreover, the preceding systematic reviews didn't include RCT comparing frankly both treatment modalities but instead they collected studies of mini dental implant, conventional dental implant separately and thereafter compared between them indirectly (Aparecido et al 2016). Patient satisfaction with the overdenture studied by authenticated questionnaires established on a visual analogue scale (VAS)("Naert et al 2004) which considered the most important and most reliable scale.
One of the most reliable criteria to assess the success of the implant is loss of the osseointegration around the implant which lead to total loss of implant and consequently failure of prosthesis so implant loss was reported in this review by counting number of implant lost during the follow up period.
Regarding the assessment of peri implant condition which represented by the marginal bone loss, A minimum of 1year of follow-up was needed as major inclusion standard to diminish bias, according to the results reported by (Adell et  The result of the meta-analysis revealed that mini dental implant resulted in more patient satisfaction compared with conventional dental implant but this difference was statistically insignificant, perhaps this result attained due to minimal surgical procedure and simple technique related to mini dental implant than conventional dental implant.
Regarding the implant loss the result of the meta-analysis revealed that the mini dental implant showed more implant loss when compared with conventional dental implant this difference was statistically significant.
Although the result of the meta-analysis revealed that mini dental implant resulted in less marginal bone loss when compared with conventional dental implant but this difference was statistically insignificant, perhaps this result attributed to the minimal surgical procedure and small diameter of the mini implant.
The limitations of this systematic review including; the total sample size of included studies was relatively small to reveal the actual influence of both treatment modalities and the include articles published only in English language could convey a source of bias.
Finally, analysis of this systematic review results must be accomplished with attentions as the included studies were very limited.

Conclusion:-
There is no strong evidence to reveal that mini implant could be used in the same degree as conventional dental implant however mini dental implant could be used as an alternative to conventional dental implant since it presents tolerable marginal bone loss, and enhancements in variables related to satisfaction of patients.

Conflict of interest: -There is no conflict of interest.
Funding: -Self-funding.