BMJ Opendenture-bearing areas, thus avoiding the possibility of further resorption, associated with...

For peer review only

Impact of fixed implant-supported prostheses in edentulous

patients: protocol for a systematic review

Journal: BMJ Open

Manuscript ID: bmjopen-2015-009288

Article Type: Protocol

Date Submitted by the Author: 01-Jul-2015

Complete List of Authors: López, Carolina; Pontificia Universidad Catolica de Chile, Faculty of Medicine Saka, Constanza; Pontificia Universidad Católica de Chile, Faculty of Medicine Rada, Gabriel; Pontificia Universidad Católica de Chile, Evidence-based Health Care Program, Faculty of Medicine Valenzuela, Daniela; Universidad de Concepción, Centro de Rehabilitación Oral Avanzada e Impalantologia (CRAI)

<b>Primary Subject Heading</b>:

Dentistry and oral medicine

Secondary Subject Heading: Rehabilitation medicine, Evidence based practice, Geriatric medicine, Patient-centred medicine

Keywords: ORAL MEDICINE, THERAPEUTICS, GERIATRIC MEDICINE, REHABILITATION MEDICINE

For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml

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arch 18, 2020 by guest. Protected by copyright.

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j.com/

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J Open: first published as 10.1136/bm

jopen-2015-009288 on 23 February 2016. D

ownloaded from

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López S., Carolina1,

Saka, H., Constanza1

Rada, Gabriel1,2,3

Valenzuela, D., Daniela4

1

Faculty of Medicine, Pontificia Universidad Católica de Chile.

2 Evidence-based Health Care Program, Faculty of Medicine, Pontificia Universidad Católica de

Chile

3 Epistemonikos foundation

4 Centro de Rehabilitación Oral Avanzada e Impalantologia (CRAI), Universidad de Concepción

Lira 63, Santiago-Chile

Emails:

Carolina López: [email protected]

Constanza Saka: [email protected]

Gabriel Rada: [email protected]

Daniela Valenzuela: [email protected]

Corresponding author: Gabriel Rada

ABSTRACT

Introduction

Edentulism is a debilitating and irreversible condition described as the “final marker of disease

burden for oral health”. Therapy with dental implants is being used on a large scale to replace

missing teeth and to rehabilitate edentulous patients with overdentures and implant-supported

fixed dentures as a method for solving the problem of instability and lack of retention associated

with conventional removable prosthesis. Fixed implant-supported prosthesis are an alternative for

implant rehabilitation treatment that allow patient to have a new fixed teeth. They can be

indicated in partial or total edentulous and they can replace single teeth, or teeth and supporting

tissues (hybrid prosthesis). They overcome the limitations of conventional dentures, increasing

stability and retention, providing functional and psychological advantages for the patients.

Methods and analysis

We will electronically search for randomised controlled trials evaluating the effects of fixed

implant-supported prostheses in edentulous patients in the following databases:

Pubmed/MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials.

We will also try to obtain literature screening references of included studies, searching for trial

protocols in the WHO International Clinical Trials Registry Platform, reviewing International Team

for Implantology conference proceedings and searching for non-published studies through Open

Gray.

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Two researchers will independently undertake selection of studies, data extraction and

assessment of the quality of included studies.

Data synthesis and subgroup analyses will be performed using special Review Manager software.

Data will be combined in a meta-analysis using a random effects model. Results will be presented

as risk ratios for dichotomous data and as mean difference or standardized mean difference for

continuous data.

Ethics and dissemination

No ethics approval is considered necessary. Results of this study will be disseminated via peer-

reviewed publications and social networks.

Registration number PROSPERO: CRD42015022086

Strengths and limitations of this study

This will be the first systematic review to assess the impact of implant-supported prostheses in

edentulous patients on their oral health, quality of life and satisfaction. It aims to provide a high-

quality synthesis of current evidence for patients and clinicians about this question. The main

limitation is the heterogeneity of studies available on the subject and the subsequent possibility to

group them to analyze the evidence on each outcome of interest that we have defined.

Keywords: Dental Prosthesis, Implant-Supported, Denture, Complete, quality of life, patients’ satisfaction

INTRODUCTION

Description of the condition

Edentulism is a debilitating and irreversible condition described as the “final marker of

disease burden for oral health”. Although the prevalence of complete tooth loss has declined over

the last decade, it remains a major disease worldwide, especially among older adults (Emami

2013). Many factors influence the prevalence of edentulism between different countries and

regions, such as education, economic status, access and opportunity to oral health care, lifestyle

and attitudes to dental care. Edentulism can lead directly to impairment, functional limitation,

physical, psychological and social disability (Locker 1988), affecting general and oral health of

individuals and, therefore, their quality of life.

Complete denture therapy has become the conventional and most prescribed treatment

option for edentulous patients, providing improved esthetics and function (Caetano 2013).

However, bone resorption of the alveolar ridge, as a consequence of edentulism, brings lack of

denture stability and retention, especially for the lower prosthesis, reducing patient’s comfort,

chewing, phonetics and esthetics. Patients wearing conventional removable prosthesis often

complain about the instability of their dentures. This leads to a feeling of insecurity, inefficient

mastication and overall dissatisfaction with their prosthesis (Prithviraj 2014).

Therapy with dental implants is being used on a large scale to replace missing teeth and to

rehabilitate edentulous patients with overdentures and implant-supported fixed dentures

(Caetano 2013). Placement of endosseous dental implants to retain and support overdentures or

fixed complete dentures have been developed as a method for solving the problem of instability

and lack of retention associated with conventional removable prosthesis (Prithviraj 2014).

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Improvement of retention and stability of the prosthetic rehabilitation through implant-supported

prosthesis leads to enhance speaking, swallowing and mastication ability and, therefore, improves

patients comfort and satisfaction.

Description of the intervention

Dental implants represent a proven treatment modality for restoration of edentulous jaws

(Papaspyridakos, 2014). Several factors play role on the decision between fixed and removable

implant dentures such as inter-foraminal space, inter-jaw relationship, oral hygiene, costs and

patient preferences (Barao 2013).

Fixed implant-supported prosthesis are an alternative for implant rehabilitation treatment

that allow patient to have a new fixed teeth. They can be indicated in partial or total edentulous

and they can replace single teeth, or teeth and supporting tissues (hybrid prosthesis). Selection of

one type or another depends on the patient bone volume and soft tissue conditions (Bedrossian

2008) in addition to economic factors and treatment cost. Fixed full-arch implant supported

prosthesis may be either screw or cement retained and are indicated in the presence of enough

bone and inter-arch space (Barao 2013). Clinical factors that may discard a fixed restoration are

mostly related to bone or soft tissues deficiencies. For this instance, rehabilitation can be done by

hybrid prosthesis.

Hybrid prosthesis are fixed rehabilitation composed of a metal-based framework covered

with complete denture components (resin and denture teeth), which is screwed onto the implants

or the abutments. This treatment modality allows patients to have a completely fixed prosthesis,

which can only be removed by a dental professional (Preciado 2013, Kwon 2014).

How the intervention might work

Fixed implant restorations are totally implant supported, with no transference of load to

denture-bearing areas, thus avoiding the possibility of further resorption, associated with tissue-

borne prosthesis (Bedrossian 2008). They also overcome the limitations of conventional dentures,

increasing stability and retention of the prosthetic rehabilitation and thus, improving speaking,

swallowing and chewing efficiency. This brings functional and psychological advantages for the

patients, enhancing their comfort and self-confidence.

Why it is important to do this review

Previous systematic reviews have addressed the impact of fixed prostheses in partial or

total edentulous persons in terms of survival and success (Kwon, 2014; Papaspyridakos, 2014;

Pjetursson, 2012¸ Lambert 2009), and biological and technical complications (Papaspyridakos,

2012; Pjetursson, 2012; Bozini 2011). However, none of these reviews have assessed the

subjective effects of fixed implant-supported prosthesis in edentulous patients. So, we not only

aim to update existing reviews, but also to supplement existing evidence by incorporating other

impact indicators such as satisfaction and quality of life.

Objectives

The aim of this systematic review is to evaluate the effects of fixed implant-supported

prostheses in edentulous patients and to assess their impact on oral health related quality of life

and satisfaction.

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METHODS

Criteria for considering studies for this review

Types of studies

Type of studies

We will include randomised controlled trials.

Types of participants

We will include studies examining healthy edentulous patients or with stabilized conditions.

Type of interventions

The interventions of interest are full-arched fixed prosthesis and hybrid prosthesis. We will not

restrict by type and number of implants or attachment system.

Comparisons of interest are conventional prosthesis and implant-supported or implant-retained

overdentures.

Types of outcomes

• Primary outcomes:

- Patient satisfaction

- Quality of life

• Secondary outcomes:

- Clinician’s appraisals for treatment success

- Cost

- Technical complications

Search methods for identification of studies

Electronic searches

We will search MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials with no

language or publication restrictions:

The following strategy will be used to search MEDLINE (PubMed):

#1 "Dental Prosthesis, Implant-Supported"[Mesh]

#2 (Dental OR denture*) AND Prosthes* AND ((Implant NEAR Supported) OR Implant-

Supported)

#3 (Dental OR denture*) AND Prosthes* AND ((Implant NEAR fixed) OR Implant-fixed)

#4 (Dental OR denture*) AND Prosthes* AND ((full-arch NEAR fixed) OR full-arch)

#5 (Dental OR denture*) AND Prosthes* AND (hybrid)

#6 #1 OR #2 OR #3 OR #4 OR #5

#7 "Mouth, Edentulous"[Mesh]

#8 "Jaw, Edentulous"[Mesh]

#9 toothless [tiab]

#10 edentul*[tiab]

#11 #7 OR #8 OR #9 #10

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#12 randomized controlled trial [pt]

#13 controlled clinical trial [pt]

#14 randomized [tiab]

#15 placebo [tiab]

#16 randomly [tiab]

#17 trial [tiab]

#18 groups [tiab]

#19 #12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18

#20 animals [mh] NOT humans [mh]

#21 #19 NOT #20

#22 #6 AND #11 AND #21

The MEDLINE strategy will be adapted to the syntax and subject headings of the other

databases.

The electronic search will be supplemented by:

- Reviewing for additional relevant studies in references of included studies.

- Searching for trial protocols through the WHO International Clinical Trials Registry

Platform.

- Searching in International Team for Implantology conference proceedings

- Searching for unpublished studies through Open Gray.

Data collection and analyses

Deduplicated results of literature will be uploaded to Covidence software

(www.covidence.org).

Selection of studies

Two authors will independently screen the titles and abstracts yielded by the search

against the inclusion criteria. We will obtain full reports for all titles that appear to meet the

inclusion criteria or where there is any uncertainty. We will seek additional information from study

authors where necessary to resolve questions about eligibility. We will resolve disagreement

through discussion. We will record the reasons for excluding trials.

Extraction and management of data

Using standardized forms two reviewers will extract data independently from each

included study. To ensure consistency, we will conduct calibration exercises before starting the

review. Data abstracted will include demographic information, methodology, population, and

intervention, comparison and outcome details.

We will resolve disagreements by discussion, and one arbitrator will adjudicate unresolved

disagreements.

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Risk of bias in individual studies

Two reviewers will independently assess risk of bias using the Cochrane Collaboration tool

for assessing risk of bias (Higgins 2011) which considers random sequence generation, allocation

concealment, blinding of participants, personnel and outcomes, incomplete outcome data,

selective outcome reporting, and other sources of bias. A judgment will be made from the

extracted information, rated as ‘high risk’ or ‘low risk’.

If there is insufficient detail reported in the study we will judge the risk of bias as ‘unclear’

and the original study investigators will be contacted for more information. Disagreements will be

resolved first by discussion and then by consulting a third author for arbitration. We will compute

graphic representations of potential bias within and across studies using RevMan 5.1 (Review

Manager 5.1).

Measures of treatments effects

For dichotomous outcomes we will express the estimate of treatment effect of an

intervention as risk ratios (RR) (improved patient satisfaction/not) together with 95% confidence

intervals (CIs). For continuous outcomes we will use mean difference and standard deviation to

summarize the data and 95% CIs. Where continuous outcomes are measured using different

scales, the treatment effect will be expressed as a standardized mean difference (SMD) with 95%

CI.

Dealing with missing data

Where possible, we will attempt to contact the original authors of the study to obtain any

missing data. If important numerical missing data cannot be obtained, an imputation method will

be used.

Assessment of heterogeneity

We will assess the variations in treatment effect from the different trials by means of a

formal statistical test (Q statistic) and the I2

statistic. We will consider heterogeneity statistically

significant if the P value is < 0.1. A rough guide to the interpretation of the I2 statistic given in the

Cochrane Handbook is: 0 to 40% might not be important, 30 to 60% may represent moderate

heterogeneity, 50 to 90% may represent substantial heterogeneity, 75 to 100% considerable

heterogeneity.

Data synthesis

We will only conduct a meta-analysis if there are studies sufficiently homogeneous in

terms of design, population, interventions and comparators reporting the same outcome

measures.

The results for clinically homogeneous studies will be meta-analysed using the Review

Manager Software (RevMan 2011). Meta-analysis will be conducted using the inverse variance

method. A random-effect model will be used. Separate meta-analyses will be presented for

specific populations or interventions if statistically significant heterogeneity is explained by some

of these, or if a convincing subgroup effect is found.

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For any outcomes which insufficient data are found for meta-analysis, a narrative

synthesis will be presented.

Subgroup analysis and investigation of heterogeneity

The following subgroups will be investigated, if possible:

- Age (<60 versus >60 years)

- Gender

- Socioeconomic status

Sensitivity analysis

We will use sensitivity analysis to assess the impact on the overall treatment effects of

inclusion of trials which do not report an intention to treat analysis, have high rates of participant

attrition, or with other missing data.

Confidence in cumulative evidence

The quality of evidence for all outcomes will be judged using the Grading of

Recommendations Assessment, Development and Evaluation working group methodology (GRADE

Working Group). The certainty of evidence will be assessed across the domains of risk of bias,

consistency, directness, precision and publication bias.

Certainty will be adjudicated as high, moderate, low, or very low.

1. REGISTRATION

In accordance with the guidelines, our systematic review protocol was registered with the

International Prospective Register of Systematic Reviews (PROSPERO) on 02 June 2015 with the

registration number: CRD42015022086.

2. CONTRIBUTIONS

GR is the guarantor. CS and CL drafted the manuscript. DV is the technical advisor on

implant-supported prostheses. All authors contributed to the development of the manuscript. All

authors devised the MEDLINE search strategy. All authors read, provided feedback and approved

the final manuscript.

3. ACKNWOLEDGEMENT

Maria Teresa Olivares contributed to devise the search strategy for MEDLINE.

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4. AMENDMENTS

If we need to amend this protocol, we will give the date of each amendment, describe the

change and give the rationale in this section. Changes will not be incorporated into the protocol.

5. SPONSOR

No funding has been received for this study. Article processing charges will be covered by

Epidemiology MSc program, Pontificia Universidad Católica de Chile

6. REFERENCES

1. Emami E, De Souza RF, Kabawat M, Feine JS. The impact of edentulism on oral and general

health. Int J Dent. 2013;2013.

2. Locker, D, “Measuring oral health: a conceptual framework,” Community Dental Health. 1988;

5(1): 3-18.

3. Caetano CR, Consani RLX, Bacchi A, Correr AB, dos Santos MBF. Influence of different flask

systems on tooth displacement and framework misfit in mandibular fixed implant-supported

complete dentures. J Prosthodont Res. 2013;57(3):213–8.

4. Prithviraj D, Madan V, Harshamayi P, Kumar CG, Vashisht R. A comparison of masticatory ef fi

ciency in conventional dentures , implant retained or supported overdentures and implant

supported fi xed prostheses : A literature review. 2014;4:153–7.

5. Papaspyridakos P, Mokti M, Chen CJ, Benic GI, Gallucci GO, Chronopoulos V. Implant and

Prosthodontic Survival Rates with Implant Fixed Complete Dental Prostheses in the Edentulous

Mandible after at Least 5 Years: A Systematic Review. Clin Implant Dent Relat Res. 2013;705–17.

6. Barão V a R, Delben J a., Lima J, Cabral T, Assunção WG. Comparison of different designs of

implant-retained overdentures and fixed full-arch implant-supported prosthesis on stress

distribution in edentulous mandible - A computed tomography-based three-dimensional finite

element analysis. J Biomech. 2013;46(7):1312–20.

7. Bedrossian E, Sullivan RM, Fortin Y, Malo P, Indresano T. Fixed-Prosthetic Implant Restoration of

the Edentulous Maxilla: A Systematic Pretreatment Evaluation Method. J Oral Maxillofac Surg.

2008;66(1):112–22.

8. Preciado A, Del Río J, Lynch CD, Castillo-Oyagüe R. A new, short, specific questionnaire (QoLIP-

10) for evaluating the oral health-related quality of life of implant-retained overdenture and

hybrid prosthesis wearers. J Dent. 2013;41(9):753–63.

9. Kwon T, Bain P a., Levin L. Systematic review of short- (5-10 years) and long-term (10 years or

more) survival and success of full-arch fixed dental hybrid prostheses and supporting implants. J

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Dent [Internet]. Elsevier Ltd; 2014;42(10):1228–41. Available from:

http://dx.doi.org/10.1016/j.jdent.2014.05.016

10. Higgins JPT, Altman DG, Sterne JAC (editors). Chapter 8: Assessing risk of bias in included

studies. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of

Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Disponible

en www.cochrane-handbook.org.

11.The GRADE Working Group. List of GRADE working group publications and grants.

http://www.gradeworkinggroup.org/index.htm (accessed 18 Jun 2015).

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Journal: BMJ Open

Manuscript ID bmjopen-2015-009288.R1

Article Type: Protocol

Date Submitted by the Author: 26-Oct-2015

Complete List of Authors: López, Carolina; Pontificia Universidad Catolica de Chile, Faculty of Medicine Saka, Constanza; Pontificia Universidad Católica de Chile, Faculty of Medicine Rada, Gabriel; Pontificia Universidad Católica de Chile, Evidence-based Health Care Program, Faculty of Medicine Valenzuela, Daniela; Universidad de Concepción, Centro de Rehabilitación Oral Avanzada e Impalantologia (CRAI)

<b>Primary Subject Heading</b>:

Dentistry and oral medicine

Secondary Subject Heading: Rehabilitation medicine, Evidence based practice, Geriatric medicine, Patient-centred medicine, Dentistry and oral medicine

Keywords: ORAL MEDICINE, THERAPEUTICS, GERIATRIC MEDICINE, REHABILITATION MEDICINE


BMJ Open on M

arch 18, 2020 by guest. Protected by copyright.

http://bmjopen.bm

j.com/

BM

J Open: first published as 10.1136/bm

jopen-2015-009288 on 23 February 2016. D

ownloaded from





López S., Carolina1,

Saka, H., Constanza1

Rada, Gabriel1,2,3

Valenzuela, D., Daniela4

1

Faculty of Medicine, Pontificia Universidad Católica de Chile.

2 Evidence-based Health Care Program, Faculty of Medicine, Pontificia Universidad Católica de

Chile

3 Epistemonikos foundation

4 Centro de Rehabilitación Oral Avanzada e Impalantologia (CRAI), Universidad de Concepción

Lira 63, Santiago-Chile

Emails:

Carolina López: [email protected]

Constanza Saka: [email protected]

Gabriel Rada: [email protected]

Daniela Valenzuela: [email protected]

Corresponding author: Gabriel Rada

ABSTRACT

Introduction

Edentulism is a debilitating and irreversible condition described as the “final marker of disease

burden for oral health”. Therapy with dental implants is being used on a large scale to replace

missing teeth and to rehabilitate edentulous patients with overdentures and implant-supported

fixed dentures as a method for solving the problem of instability and lack of retention associated

with conventional removable prosthesis. Fixed implant-supported prosthesis are an alternative for

implant rehabilitation treatment that allow patient to have a new fixed teeth. They can be

indicated in partial or total edentulous and they can replace single teeth, or teeth and supporting

tissues (hybrid prosthesis). They overcome the limitations of conventional dentures, increasing

stability and retention, providing functional and psychological advantages for the patients.

Methods and analysis

We will electronically search for randomised controlled trials evaluating the effects of fixed

implant-supported prostheses in edentulous patients in the following databases:

Pubmed/MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials.

We will also try to obtain literature screening references of included studies, searching for trial

protocols in the WHO International Clinical Trials Registry Platform, reviewing International Team

for Implantology conference proceedings and searching for non-published studies through Open

Gray.

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Two researchers will independently undertake selection of studies, data extraction and

assessment of the quality of included studies.

Data synthesis and subgroup analyses will be performed using special Review Manager software.

Data will be combined in a meta-analysis using a random effects model. Results will be presented

as risk ratios for dichotomous data and as mean difference or standardized mean difference for

continuous data.

Ethics and dissemination

No ethics approval is considered necessary. Results of this study will be disseminated via peer-

reviewed publications and social networks.

Registration number PROSPERO: CRD42015022086

Strengths and limitations of this study

This will be the first systematic review to assess the impact of implant-supported prostheses in

edentulous patients on their oral health, quality of life and satisfaction. It aims to provide a high-

quality synthesis of current evidence for patients and clinicians about this question. The main

limitation is the heterogeneity of studies available on the subject and the subsequent possibility to

group them to analyze the evidence on each outcome of interest that we have defined.

Keywords: Dental Prosthesis, Implant-Supported, Denture, Complete, quality of life, patients’ satisfaction

INTRODUCTION

Description of the condition

Edentulism is a debilitating and irreversible condition described as the “final marker of

disease burden for oral health”. Although the prevalence of complete tooth loss has declined over

the last decade, it remains a major disease worldwide, especially among older adults (1). Many

factors influence the prevalence of edentulism between different countries and regions, such as

education, economic status, access and opportunity to oral health care, lifestyle and attitudes to

dental care. Edentulism can lead directly to impairment, functional limitation, physical,

psychological and social disability (2), affecting general and oral health of individuals and, therefore,

their quality of life.

Complete denture therapy has become the conventional and most prescribed treatment

option for edentulous patients, providing improved esthetics and function (3). However, bone

resorption of the alveolar ridge, as a consequence of edentulism, brings lack of denture stability

and retention, especially for the lower prosthesis, reducing patient’s comfort, chewing, phonetics

and esthetics. Patients wearing conventional removable prosthesis often complain about the

instability of their dentures. This leads to a feeling of insecurity, inefficient mastication and overall

dissatisfaction with their prosthesis (4).

Therapy with dental implants is being used on a large scale to replace missing teeth and to

rehabilitate edentulous patients with overdentures and implant-supported fixed dentures (3).

Placement of endosseous dental implants to retain and support overdentures or fixed complete

dentures has been developed as a method for solving the problem of instability and lack of

retention associated with conventional removable prosthesis (4). Improvement of retention and

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stability of the prosthetic rehabilitation through implant-supported prosthesis leads to enhance

speaking, swallowing and mastication ability and, therefore, improves patients comfort and

satisfaction.

Description of the intervention

Dental implants represent a proven treatment modality for restoration of edentulous jaws

(5). Several factors play role on the decision between fixed and removable implant dentures such as

inter-foraminal space, inter-jaw relationship, oral hygiene, costs and patient preferences (6).

Fixed implant-supported prosthesis are an alternative for implant rehabilitation treatment

that allow patient to have a new fixed teeth. They can be indicated in partial or total edentulous

and they can replace single teeth, or teeth and supporting tissues (hybrid prosthesis). Selection of

one type or another depends on the patient bone volume and soft tissue conditions (7) in addition

to economic factors and treatment cost. Fixed full-arch implant supported prosthesis may be

either screw or cement retained and are indicated in the presence of enough bone and inter-arch

space (6). Clinical factors that may discard a fixed restoration are mostly related to bone or soft

tissues deficiencies. For this instance, rehabilitation can be done by hybrid prosthesis.

Hybrid prosthesis are fixed rehabilitation composed of a metal-based framework covered

with complete denture components (resin and denture teeth), which is screwed onto the implants

or the abutments. This treatment modality allows patients to have a completely fixed prosthesis,

which can only be removed by a dental professional (8,9).

How the intervention might work

Fixed implant restorations are totally implant supported, with no transference of load to

denture-bearing areas, thus avoiding the possibility of further resorption, associated with tissue-

borne prosthesis (7). They also overcome the limitations of conventional dentures, increasing

stability and retention of the prosthetic rehabilitation and thus, improving speaking, swallowing

and chewing efficiency. This brings functional and psychological advantages for the patients,

enhancing their comfort and self-confidence.

Why it is important to do this review

Previous systematic reviews have addressed the impact of fixed prostheses in partial or

total edentulous persons in terms of survival and success (Kwon, 2014; Papaspyridakos, 2014;

Pjetursson, 2012¸ Lambert 2009), and biological and technical complications (Papaspyridakos,

2012; Pjetursson, 2012; Bozini 2011). However, none of these reviews have assessed the

subjective effects of fixed implant-supported prosthesis in edentulous patients. So, we not only

aim to update existing reviews, but also to supplement existing evidence by incorporating other

impact indicators such as satisfaction and quality of life.

Objectives

Our main objective is to evaluate the effects of fixed implant-supported prostheses in

edentulous patients and to assess their impact on satisfaction and quality of life when compared

to conventional prosthesis or overdentures.

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METHODS

Criteria for considering studies for this review

Types of studies

Type of studies

We will include randomised controlled trials.

Types of participants

We will include studies examining healthy edentulous patients or with stabilized conditions.

Type of interventions

The interventions of interest are full-arched fixed prosthesis and hybrid prosthesis. We will not

restrict by type and number of implants or attachment system.

Comparisons of interest are conventional prosthesis and implant-supported or implant-retained

overdentures.

Types of outcomes

• Primary outcomes:

- Patient satisfaction

- Quality of life

• Secondary outcomes:

- Clinician’s appraisals for treatment success

- Cost

- Technical complications

Search methods for identification of studies

Electronic searches

We will search MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials with no

language or publication restrictions:

The following strategy will be used to search MEDLINE (PubMed):

#1 "Dental Prosthesis, Implant-Supported"[Mesh]

#2 (Dental OR denture*) AND Prosthes* AND ((Implant NEAR Supported) OR Implant-

Supported)

#3 (Dental OR denture*) AND Prosthes* AND ((Implant NEAR fixed) OR Implant-fixed)

#4 (Dental OR denture*) AND Prosthes* AND ((full-arch NEAR fixed) OR full-arch)

#5 (Dental OR denture*) AND Prosthes* AND (hybrid)

#6 #1 OR #2 OR #3 OR #4 OR #5

#7 "Mouth, Edentulous"[Mesh]

#8 "Jaw, Edentulous"[Mesh]

#9 toothless [tiab]

#10 edentul*[tiab]

#11 #7 OR #8 OR #9 #10

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#12 randomized controlled trial [pt]

#13 controlled clinical trial [pt]

#14 randomized [tiab]

#15 placebo [tiab]

#16 randomly [tiab]

#17 trial [tiab]

#18 groups [tiab]

#19 #12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18

#20 animals [mh] NOT humans [mh]

#21 #19 NOT #20

#22 #6 AND #11 AND #21

The MEDLINE strategy will be adapted to the syntax and subject headings of the other

databases.

The electronic search will be supplemented by:

- Reviewing for additional relevant studies in references of included studies.

- Searching for trial protocols through the WHO International Clinical Trials Registry

Platform.

- Searching in International Team for Implantology conference proceedings

- Searching for unpublished studies through Open Grey.

Data collection and analyses

Deduplicated results of literature will be uploaded to Covidence software

(www.covidence.org).

Selection of studies

Two authors will independently screen the titles and abstracts yielded by the search

against the inclusion criteria. We will obtain full reports for all titles that appear to meet the

inclusion criteria or where there is any uncertainty. We will seek additional information from study

authors where necessary to resolve questions about eligibility. We will resolve disagreement

through discussion. We will record the reasons for excluding trials.

Extraction and management of data

Using standardized forms two reviewers will extract data independently from each

included study. To ensure consistency, we will conduct calibration exercises before starting the

review. Data abstracted will include demographic information, methodology, population, and

intervention, comparison and outcome details.

We will resolve disagreements by discussion, and one arbitrator will adjudicate unresolved

disagreements.

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Risk of bias in individual studies

Two reviewers will independently assess risk of bias using the Cochrane Collaboration tool

for assessing risk of bias (10) which considers random sequence generation, allocation concealment,

blinding of participants, personnel and outcomes, incomplete outcome data, selective outcome

reporting, and other sources of bias. A judgment will be made from the extracted information,

rated as ‘high risk’ or ‘low risk’.

If there is insufficient detail reported in the study we will judge the risk of bias as ‘unclear’

and the original study investigators will be contacted for more information. Disagreements will be

resolved first by discussion and then by consulting a third author for arbitration. We will compute

graphic representations of potential bias within and across studies using RevMan 5.1 (Review

Manager 5.1).

Measures of treatments effects

For dichotomous outcomes we will express the estimate of treatment effect of an

intervention as risk ratios (RR) (improved patient satisfaction/not) together with 95% confidence

intervals (CIs). For continuous outcomes we will use mean difference and standard deviation to

summarize the data and 95% CIs. Where continuous outcomes are measured using different

scales, the treatment effect will be expressed as a standardized mean difference (SMD) with 95%

CI.

Dealing with missing data

Where possible, we will attempt to contact the original authors of the study to obtain any

missing data. If important numerical missing data cannot be obtained, an imputation method will

be used.

Assessment of heterogeneity

We will assess the variations in treatment effect from the different trials by means of a

formal statistical test (Q statistic) and the I2

statistic. We will consider heterogeneity statistically

significant if the P value is < 0.1. A rough guide to the interpretation of the I2 statistic given in the

Cochrane Handbook is: 0 to 40% might not be important, 30 to 60% may represent moderate

heterogeneity, 50 to 90% may represent substantial heterogeneity, 75 to 100% considerable

heterogeneity.

Data synthesis

We will only conduct a meta-analysis if there are studies sufficiently homogeneous in

terms of design, population, interventions and comparators reporting the same outcome

measures.

The results for clinically homogeneous studies will be meta-analysed using the Review

Manager Software (RevMan 2011). Meta-analysis will be conducted using the inverse variance

method. A random-effect model will be used. Separate meta-analyses will be presented for

specific populations or interventions if statistically significant heterogeneity is explained by some

of these, or if a convincing subgroup effect is found.

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For any outcomes which insufficient data are found for meta-analysis, a narrative

synthesis will be presented.

Subgroup analysis and investigation of heterogeneity

The following subgroups will be investigated, if possible:

- Age (<60 versus >60 years)

- Gender

- Socioeconomic status

Assessment of reporting biases

We will investigate the presence of publication bias visually with the use of funnel plots.

We will base evidence of asymmetry on p < 0.10, and present intercepts with 90% CIs. Other

reporting biases, including outcome reporting bias, will be evaluated through discrepancies

between the registered protocol and the final publication. If we cannot find the record of a study

in the WHO International Clinical Trials Registry Platform, we will contact authors for more

information.

Sensitivity analysis

We will use sensitivity analysis to assess the impact on the overall treatment effects of

inclusion of trials which do not report an intention to treat analysis, have high rates of participant

attrition, or with other missing data.

Confidence in cumulative evidence

The quality of evidence for all outcomes will be judged using the Grading of

Recommendations Assessment, Development and Evaluation working group methodology (GRADE

Working Group) (11). The certainty of evidence will be assessed across the domains of risk of bias,

consistency, directness, precision and publication bias.

Certainty will be adjudicated as high, moderate, low, or very low.

1. REGISTRATION

In accordance with the guidelines, our systematic review protocol was registered with the

International Prospective Register of Systematic Reviews (PROSPERO) on 02 June 2015 with the

registration number: CRD42015022086.

2. CONTRIBUTIONS

GR is the guarantor. CS and CL drafted the manuscript. DV is the technical advisor on

implant-supported prostheses. All authors contributed to the development of the manuscript. All

authors devised the MEDLINE search strategy. All authors read, provided feedback and approved

the final manuscript.

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3. ACKNOWLEDGEMENT

Maria Teresa Olivares contributed to devise the search strategy for MEDLINE.

4. AMENDMENTS

If we need to amend this protocol, we will give the date of each amendment, describe the

change and give the rationale in this section. Changes will not be incorporated into the protocol.

5. SPONSOR

No funding has been received for this study. Article processing charges will be covered by

Epidemiology MSc program, Pontificia Universidad Católica de Chile

6. REFERENCES

1. Emami E, De Souza RF, Kabawat M, Feine JS. The impact of edentulism on oral and general

health. Int J Dent. 2013;2013.

2. Locker, D, “Measuring oral health: a conceptual framework,” Community Dental Health. 1988;

5(1): 3-18.

3. Caetano CR, Consani RLX, Bacchi A, Correr AB, dos Santos MBF. Influence of different flask

systems on tooth displacement and framework misfit in mandibular fixed implant-supported

complete dentures. J Prosthodont Res. 2013;57(3):213–8.

4. Prithviraj D, Madan V, Harshamayi P, Kumar CG, Vashisht R. A comparison of masticatory ef fi

ciency in conventional dentures , implant retained or supported overdentures and implant

supported fi xed prostheses : A literature review. 2014;4:153–7.

5. Papaspyridakos P, Mokti M, Chen CJ, Benic GI, Gallucci GO, Chronopoulos V. Implant and

Prosthodontic Survival Rates with Implant Fixed Complete Dental Prostheses in the Edentulous

Mandible after at Least 5 Years: A Systematic Review. Clin Implant Dent Relat Res. 2013;705–17.

6. Barão V a R, Delben J a., Lima J, Cabral T, Assunção WG. Comparison of different designs of

implant-retained overdentures and fixed full-arch implant-supported prosthesis on stress

distribution in edentulous mandible - A computed tomography-based three-dimensional finite

element analysis. J Biomech. 2013;46(7):1312–20.

7. Bedrossian E, Sullivan RM, Fortin Y, Malo P, Indresano T. Fixed-Prosthetic Implant Restoration of

the Edentulous Maxilla: A Systematic Pretreatment Evaluation Method. J Oral Maxillofac Surg.

2008;66(1):112–22.

8. Preciado A, Del Río J, Lynch CD, Castillo-Oyagüe R. A new, short, specific questionnaire (QoLIP-

10) for evaluating the oral health-related quality of life of implant-retained overdenture and

hybrid prosthesis wearers. J Dent. 2013;41(9):753–63.

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9. Kwon T, Bain P a., Levin L. Systematic review of short- (5-10 years) and long-term (10 years or

more) survival and success of full-arch fixed dental hybrid prostheses and supporting implants. J

Dent [Internet]. Elsevier Ltd; 2014;42(10):1228–41. Available from:

http://dx.doi.org/10.1016/j.jdent.2014.05.016

10. Higgins JPT, Altman DG, Sterne JAC (editors). Chapter 8: Assessing risk of bias in included

studies. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of

Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Disponible

en www.cochrane-handbook.org.

11.The GRADE Working Group. List of GRADE working group publications and grants.

http://www.gradeworkinggroup.org/index.htm (accessed 18 Jun 2015).

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PRISMA-P (Preferred Reporting Items for Systematic review and Meta-Analysis Protocols) 2015 checklist: recommended items to

address in a systematic review protocol*

Section and topic Item No Checklist item

ADMINISTRATIVE INFORMATION Title: Impact of fixed implant-supported prostheses in edentulous patients: protocol for a systematic review

Identification 1a Identify the report as a protocol of a systematic review: YES. Identified as protocol in the title.

Update 1b If the protocol is for an update of a previous systematic review, identify as such. This is the first document and not an

update

Registration 2 If registered, provide the name of the registry (such as PROSPERO) and registration number. PROSPERO reference

CRD42015022086

Authors:

Contact 3a Provide name, institutional affiliation, e-mail address of all protocol authors; provide physical mailing address of

corresponding author. YES. Names, affiliations and emails of all authors provided. Physical mailing address of

corresponding author provided.

Contributions 3b Describe contributions of protocol authors and identify the guarantor of the review. YES. Contributions and guarantor

described in page 7

Amendments 4 If the protocol represents an amendment of a previously completed or published protocol, identify as such and list changes;

otherwise, state plan for documenting important protocol amendments. This is the original protocol. Important protocol

amendments will be documented and submitted to the registering body in compliance with PROSPERO registration

Support:

Sources 5a Indicate sources of financial or other support for the review. Yes. Described in page 8

Sponsor 5b Provide name for the review funder and/or sponsor. Yes. Described in page 8

Role of sponsor or funder 5c Describe roles of funder(s), sponsor(s), and/or institution(s), if any, in developing the protocol. Yes. Described in page 8

INTRODUCTION

Rationale 6 Describe the rationale for the review in the context of what is already known. Yes. Described in pages 2 and 3.

Objectives 7 Provide an explicit statement of the question(s) the review will address with reference to participants, interventions,

comparators, and outcomes (PICO). Yes. Described in page 3.

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METHODS

Eligibility criteria 8 Specify the study characteristics (such as PICO, study design, setting, time frame) and report characteristics (such as years

considered, language, publication status) to be used as criteria for eligibility for the review. Yes. Described under

‘Methods/Criteria for considering studies for this review’ in page 4.

Information sources 9 Describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other

grey literature sources) with planned dates of coverage. Yes. Described under ‘Methods/Search methods for

identification of studies’ in page 4.

Search strategy 10 Present draft of search strategy to be used for at least one electronic database, including planned limits, such that it could be

repeated. Yes. Described under ‘Methods/Search methods for identification of studies’ in pages 4 and 5.

Study records:

Data management 11a Describe the mechanism(s) that will be used to manage records and data throughout the review. Yes. Described in page 5.

Selection process 11b State the process that will be used for selecting studies (such as two independent reviewers) through each phase of the

review (that is, screening, eligibility and inclusion in meta-analysis). Yes. Described in page 5.

Data collection process 11c Describe planned method of extracting data from reports (such as piloting forms, done independently, in duplicate), any

processes for obtaining and confirming data from investigators. Yes. Described in page 5.

Data items 12 List and define all variables for which data will be sought (such as PICO items, funding sources), any pre-planned data

assumptions and simplifications. Yes. Described in page 5.

Outcomes and prioritization 13 List and define all outcomes for which data will be sought, including prioritization of main and additional outcomes, with

rationale. Yes. Described under ‘Methods/Criteria for considering studies for this review’ in page 4.

Risk of bias in individual studies 14 Describe anticipated methods for assessing risk of bias of individual studies, including whether this will be done at the

outcome or study level, or both; state how this information will be used in data synthesis. Yes. Described under

‘Methods/ Risk of bias in individual studies’ in page 6.

Data synthesis 15a Describe criteria under which study data will be quantitatively synthesised. Yes. Described under ‘Methods/Data

synthesis ’ in pages 6 and 7.

15b If data are appropriate for quantitative synthesis, describe planned summary measures, methods of handling data and

methods of combining data from studies, including any planned exploration of consistency (such as I2, Kendall’s τ). Yes.

Described in pages 6 and 7.

15c Describe any proposed additional analyses (such as sensitivity or subgroup analyses, meta-regression). . Yes. Described

under ‘Methods/Subgroup analysis and investigation of heterogeneity’ and under ‘Methods/sensitivity analysis’ in

pages 6 and 7

15d If quantitative synthesis is not appropriate, describe the type of summary planned. Yes. Described under ‘Methods/Data

synthesis ’ in page 7.

Meta-bias(es) 16 Specify any planned assessment of meta-bias(es) (such as publication bias across studies, selective reporting within

studies). Yes. Described under ‘Methods/Assessment of reporting biases’ in page 7.

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Confidence in cumulative evidence 17 Describe how the strength of the body of evidence will be assessed (such as GRADE). Yes. Described under

‘Methods/confidence in cumulative evidence ’ in page 7.

From: Shamseer L, Moher D, Clarke M, Ghersi D, Liberati A, Petticrew M, Shekelle P, Stewart L, PRISMA-P Group. Preferred reporting items for systematic review and

meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ. 2015 Jan 2;349(jan02 1):g7647.

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