20
Wissam Abboud
Fifth Year, Group 13
EVALUATION
OF THE ASSOCIATION BETWEEN SINUS
MEMBRANE PERFORATION DURING SINUS
AUGMENTATION PROCEDURE
AND DENTAL IMPLANT FAILURE RATE
Master’s ThesisSupervisor:
DDS, PhD Povilas Daugėla
2
FINAL MASTER‘S THESIS IS CONDUCTED
AT THE DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY.
STATEMENT OF THESIS ORIGINALITY
I confirm that the submitted Final Master‘s Thesis (tittle). “EVALUATION OF THE ASSOCIATION
BETWEEN SINUS MEMBRANE PERFORATION DURING MAXILLARY SINUS AUGMENTATION PROCEDURE AND DENTAL IMPLANT FAILURE RATE” 1. Is done by myself.
2. Has not been used at another university in Lithuania or abroad.
3. I did not used any additional sources that are not listed in the Thesis, and I provide a complete list of references.
I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.
(2020.04.28) (Wissam Abboud) ( )
CONCLUSION OF FINAL MASTER‘S THESIS ACADEMIC SUPERVISOR
ON THE DEFENSE OF THE THESIS
I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.
(2020.04.28) (Povilas Daugėla) (signature)
FINAL MASTER‘S THESIS IS APPROVED AT THE DEPARTMENT
I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.(date of approval) (name of the Department and full name of the Head of the Department) (signature)
Final Master‘s Thesis reviewer
I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.
(full name) (signature)
Evaluation of Final Master‘s Thesis Defense Board:
I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.
3 LITHUANIAN UNIVERSITY OF HEALTH SCIENCES
MEDICAL ACADEMY
FACULTYOFODONTOLOGY
CLINIC OF ORAL AND MAXILLOFACIAL SURGERY
EVALUATION OF THE ASSOCIATION BETWEEN SINUS MEMBRANE PERFORATION DURING MAXILLARY SINUS
AUGMENTATION PROCEDURE AND DENTAL IMPLANT FAILURE RATE
Master’s Thesis
The thesis was done
by student ………... supervisor ………...
(name surname, year, group) (degree, name surname)
……….. ………
(signature) (signature)
……… 20…. ……… 20….
(day/month) (day/month)
4 EVALUATION TABLE OF THE MASTER’S THESIS
OF THE TYPE OF SYSTEMIC REVIEW OF SCIENTIFIC LITERATURE Evaluation: ... Reviewer: ...
(scientific degree. name and surname) Reviewing date: ...
No. MT parts MT evaluation aspects
Compliance with MT requirements and evaluation Yes Partially No 1 Summary (0.5 point)
Is summary informative and in compliance with the
thesis content and requirements? 0.3 0.1 0
2 Are keywords in compliance with the thesis essence? 0.2 0.1 0
3
Introduc-tion, aim and tasks
(1 point)
Are the novelty, relevance and significance of the work
justified in the introduction of the thesis? 0.4 0.2 0
4 Are the problem, hypothesis, aim and tasks formed clearly and properly? 0.4 0.2 0
5 Are the aim and tasks interrelated? 0.2 0.1 0
6 Selection criteria of the studies, search methods and strategy (3.4 points)
Is the protocol of systemic review present? 0.6 0.3 0
7
Were the eligibility criteria of articles for the selected protocol determined (e.g., year, language, publication condition, etc.)
0.4 0.2 0
8
Are all the information sources (databases with dates of coverage, contact with study authors to identify additional studies) described and is the last search day indicated?
0.2 0.1 0
9
Is the electronic search strategy described in such a way that it could be repeated (year of search, the last search day; keywords and their combinations; number of found and selected articles according to the combinations of keywords)?
0.4 0.1 0
10
Is the selection process of studies (screening, eligibility, included in systemic review or, if applicable, included in the meta-analysis) described?
0.4 0.2 0
11
Is the data extraction method from the articles (types of investigations, participants, interventions, analysed factors, indexes) described?
0.4 0.2 0
12
Are all the variables (for which data were sought and any assumptions and simplifications made) listed and defined?
0.4 0.2 0
13
Are the methods, which were used to evaluate the risk of bias of individual studies and how this information is to
be used in data synthesis, described? 0.2 0.1 0
14 Were the principal summary measures (risk ratio, difference in means) stated? 0.4 0.2 0 15 Systemiza-tion and analysis of data (2.2 points)
Is the number of studies screened: included upon assessment for eligibility and excluded upon giving the reasons in each stage of exclusion presented?
0.6 0.3 0
16
Are the characteristics of studies presented in the included articles, according to which the data were extracted (e.g., study size, follow-up period, type of respondents) presented?
0.6 0.3 0
5
for each study presented? (a) simple summary data for each intervention group; b) effect estimates and confidence intervals)
18 Are the extracted and systemized data from studies presented in the tables according to individual tasks? 0.6 0.3 0 19
Discussion (1.4 points)
Are the main findings summarized and is their relevance
indicated? 0.4 0.2 0
20 Are the limitations of the performed systemic review discussed? 0.4 0.2 0
21 Does author present the interpretation of the results? 0.4 0.2 0
22
Conclusions (0.5 points)
Do the conclusions reflect the topic, aim and tasks of the
Master’s thesis? 0.2 0.1 0
23 Are the conclusions based on the analysed material? 0.2 0.1 0
24 Are the conclusions clear and laconic? 0.1 0.1 0
25
References (1 point)
Is the references list formed according to the
requirements? 0.4 0.2 0
26 Are the links of the references to the text correct? Are
the literature sources cited correctly and precisely? 0.2 0.1 0
27 Is the scientific level of references suitable for Master’s thesis? 0.2 0.1 0
28
Do the cited sources not older than 10 years old form at least 70% of sources, and the not older than 5 years – at least 40%?
0.2 0.1 0
Additional sections, which may increase the collected number of points
29 Annexes Do the presented annexes help to understand the
analysed topic? +0.2 +0.1 0
30
Practical
recommen-dations
Are the practical recommendations suggested and are
they related to the received results? +0.4 +0.2 0
31
Were additional methods of data analysis and their results used and described (sensitivity analyses, meta-regression)?
+1 +0.5 0
32
Was meta-analysis applied? Are the selected statistical methods indicated? Are the results of each meta-analysis
presented? +2 +1 0
General requirements, non-compliance with which reduce the number of points
33
General require-ments
Is the thesis volume sufficient (excluding annexes)?
15-20 pages (-2 points)
<15 pages (-5 points)
34 Is the thesis volume increased artificially? -2 points -1 point
35 Does the thesis structure satisfy the requirements of Master’s thesis? -1 point -2 points 36 Is the thesis written in correct language, scientifically, logically and laconically? -0.5 point -1 points
37 Are there any grammatical, style or computer
literacy-related mistakes? -2 points -1 points
38 Is text consistent, integral, and are the volumes of its structural parts balanced? -0.2 point -0.5 points
39 Amount of plagiarism in the thesis. >20%
(not evaluated) 40
Is the content (names of sections and sub-sections and enumeration of pages) in compliance with the thesis structure and aims?
-0.2 point -0.5 points
41 Are the names of the thesis parts in compliance with the text? Are the titles of sections and sub-sections distinguished
6
logically and correctly?
42 Are there explanations of the key terms and abbreviations (if needed)? -0.2 point -0.5 points 43
Is the quality of the thesis typography (quality of printing, visual aids, binding) good?
-0.2 point -0.5 points
*In total (maximum 10 points):
*Remark: the amount of collected points may exceed 10 points.
Reviewer’s comments: ___________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ _________________________________________ ___________________________
7
TABLE OF CONTENTS
1.SUMMARY ... 8
2.INTRODUCTION ... 9
3.SEARCH METHODS AND STRATEGY ... 12
Selection criteria ... 12
Screening process ... 13
Information sources ... 13
Risk of bias assessment ... 18
4.RESULTS ... 20
5.DISCUSSION ... 23
6.CONCLUSIONS ... 25
7.CLINICAL RELEVANCE ... 26
8.RECOMMENDATIONS FOR FURTHER RESEARCH ... 26
8 EVALUATION OF THE ASSOCIATION BETWEEN SINUS MEMBRANE PERFORATION DURING MAXILLARY SINUS AUGMENTATION PROCEDURE AND DENTAL IMPLANT
FAILURE RATE
SUMMARY
Introduction: This systematic review aims to evaluate whether a correlation between Schneiderian membrane perforations and implant failure is confirmed in scientific research studies.
Materials and methods: Electronic databases PubMed, Embase, Ovid Medline, Springer Link and Wiley online library were searched. Eligibility criteria enclosed prospective and retrospective cohort clinical trials and randomized clinical trials, concerning patients subjected to maxillary sinus floor elevation, in which membrane perforation occurred.
Results: Two prospective clinical studies and seven retrospective clinical trials were included for the final review. A total of 1628 patients (3253 implants) were treated. The follow-up period of the studies included ranged from 6 to 98 months. Studies evaluated had an unclear risk of bias. Most of the investigated studies reported that, the occurrence of a perforated maxillary sinus membrane did not have a significant effect on implant failure rate compared to intact sinus membranes during maxillary sinus augmentation procedure.
Conclusion: From the accessible data it is proposed that sinus membrane perforation did not have an unfavorable effect on implant survival rates if the membrane is repaired appropriately. Long term studies are essential in order to confirm these results.
Keywords: “Maxillary sinus membrane perforation”, “implant failure”, “sinus floor augmentation”, “Schneiderian membrane”.
9
INTRODUCTION
Maxillary sinus is the largest paranasal sinus, with a pyramidal shape. The function of sinuses is to reduce the weight of the skull, and produce mucous that moistens nose internally. Schneiderian membrane is a fine bilaminar mucoperiosteal membrane that borders the maxillary sinus. It consists of respiratory type epithelium, pseudostratified columnar ciliated epithelium with a variable thickness ranging from 0.13 to 0.5 mm. The physiologic significance of membrane cilia is to direct mucous discharge and debris towards ostium so that in normal functions drainage is steadily preserved [1, 2]. The membrane is a critical barricade for the preservation and defense of sinus cavity.
An essential component to implant success is the alveolar bone quantity and quality. Adequate bone support is the principal requisite to achieve osseointegration of implants [2]. Installation of implants in posterior edentulous maxilla in most cases is demanding due to inadequate bone quantity and close contiguity of sinus. With increasing age, the volume of maxillary sinus rises constantly, this process is called pneumatization and it ensues in an inferior direction [3]. Tooth extraction accelerates this process due to the action of osteoclasts which is inaugurated from the alveolar bone and maxillary sinus membrane [2]. As an aftereffect of pneumatization, alveolar bone can diminish considerably in the areas designated for implant placement.
Maxillary sinus augmentation, otherwise called sinus floor elevation, is an operation whose purpose is the increment of vertical bone height of the alveolar bone to facilitate dental implant placement [2]. This procedure has gained popularity through the years therefore numerous techniques and materials can be employed.
Two main methods for maxillary sinus elevation comprise the direct and indirect techniques. The direct technique, otherwise called the lateral window technique was initially reported in 1980 by Boyne and James [2]. This approach ensures access to the lateral sinus wall by raising a full-thickness mucoperiosteal flap from the alveolar crest with vertical releasing incisions. Conventionally high-speed surgical burs have been utilized for preparation of a window in the lateral sinus wall to approach the Schneiderian membrane. Of late the employment of piezoelectric units has been encouraged as a substitute to minimize the likelihood of perforation of the membrane. Once access is accomplished, the membrane is cautiously dissevered from the surrounding bone in 3 dimensions using curettes, and a bone graft is placed in the space that has been created. Implants are placed either simultaneously or after the graft has healed [4].
An alternative to lateral window technique, a transcrestal membrane elevation technique, using osteotomes was stated by Summers and many modifications on the transcrestal approach have been
10 described [5]. In 1994, Summers described a modified approach by using a set of osteotomes with increasing diameters for both implant site preparation and sinus floor elevation [5]. This technique allows to increase the bone density resulting in better primary stability of inserted dental implants [2].
Perforation of sinus membrane is the most frequent complication that has been noted since earliest reports on procedure [6]. Additional complications include bleeding, displacement of implant into sinus. The occurrence of membrane perforations in osteotome-mediated sinus lift has been stated to extend between 4 and 25%. Whereas in lateral window technique occurs in 7–10% to 35% of cases [2].
It is suggested that Cone-beam CT scans should be taken beforehand to evaluate anatomical variations that may heighten the potential of perforation these include thin Schneiderian membrane or difficult maxillary sinus anatomy. The membrane may be perforated during osteotomy preparation or membrane elevation. Elements that can influence sinus membrane perforation consist of forceful instrumentation during elevation and thickness of the maxillary sinus membrane [7]. Perforation during preparation may be minimized by being careful when using a high-speed bur or by utilizing a piezoelectric unit.
If perforation ensues, it is substantial to make an effort to elevate the membrane around the perforation. However, supposing the perforation is large this might not be feasible. Small perforations are able to be repaired by suturing or by placing a resorbable collagen membrane on top of the perforated area after it has been elevated and prior to the addition of bone graft. In some cases, even if the perforation is small and relocated in an area of elevated mucosa folds then there is no need for treatment. Larger perforations are more challenging. They are frequently restored using larger resorbable membranes anchored to the superior surface of the osteotomy window with bone tacks before bone augmentation [1].
It is evident in literature that membrane perforations are correlated with the presence of postoperative complications such as acute or chronic sinus infection, bacterial invasion, swelling, bleeding, and loss of the graft material and a disturbance of normal sinus physiologic function [6]. It is not clear, however, whether an association between membrane perforations and implant failure exists, thus the aim of this systematic review was to evaluate the association between maxillary sinus membrane perforation and dental implant failure.
Focus question: Is there an association between sinus membrane perforation during maxillary sinus augmentation procedure and dental implant failure rate?
11 Task: To compare predominance of implant loss when they are inserted under the perforated and non-perforated sinus membrane during maxillary sinus elevation surgery.
12
SEARCH METHODS AND STRATEGY
The protocol for this review was based primarily on PRISMA statement [8].Approval by the local bioethics committee was granted (No. BEC-OF (U)-126).
Clinical questions were separated and organized using the PICOS strategy. Table 1. PICOS strategy
Component Description
Population (P) Patients with edentulous maxilla or posterior edentulous maxilla where maxillary sinus augmentation is entailed for implant placement.
Intervention (I) Simultaneous or delayed implant placement in
patients that were subjected to maxillary sinus augmentation procedure.
Comparison (C) Number of implants failed in patients with
perforated maxillary sinus membrane versus not perforated membrane.
Outcome (O) Association between maxillary sinus
membrane perforation and dental implant failure rate.
Study design Controlled clinical trials, randomized
controlled clinical trials, prospective cohort studies or retrospective controlled studies.
Selection criteria Inclusion criteria
o Clinical trials, prospective or retrospective cohort studies, randomized controlled clinical trials, controlled clinical trials in English language published from January 2010 until February 2020 in scientific journals.
o Studies assessing sinus elevation either with lateral window access or osteotome approach with simultaneous or delayed implant placement
o Studies evaluating implant survival rate after maxillary sinus membrane perforation and stating the record of failed implants
13 o Less than five percent of the patients were lost during follow-up
o Patients older than 18 years old included in the study
o Minimum follow-up duration of 6 months after implant loading Exclusion criteria
o In vitro and laboratory studies o Case reports and reviews o Animal studies
o Studies not stating the statistics of failed implants
o Studies including patients with untreated periodontal disease or any other health compromising condition, excluding smoking
Screening process
Screening process started with an analysis of titles and abstracts. In the second step full-text papers were selected for careful reading and were assessed against eligibility criteria for future data extraction.
Information sources
An electronic search in PubMed, Embase, Ovid Medline, Springer Link and Wiley online library was performed, to identify applicable studies published in the English language from January 2010 until February 2020.
Furthermore, the bibliography of the selected articles was manually searched to identify additional relevant articles.
Search
The following keyword combinations were employed for the electronic search:
#1 ‘Atrophic posterior maxilla’ [All Fields] OR ‘edentulous maxilla’ [All Fields] #2 ‘Sinus Augmentation’ [All Fields] OR ‘Sinus membrane elevation’ [All Fields] OR ‘Membrane Perforation’ [All Fields] OR ‘Simultaneous Implants’ [All Fields] OR Implant Failure [All Fields] #3 Dental survival [All Fields] OR dental failure [All Fields]. Search combinations performed were #1 AND #2 AND #3 AND #4
14 Figure 1: PRISMA flow chart
Pubmed, Ovid Medline, Embase, Springer Link, Wiley Online Library advanced search (n =490)
(n = )
Additional records identified through other sources
(n = 0)
Records after duplicates removed (n =480)
Records screened (n =480)
Records excluded -Articles older than 10 years: 161
-Not in English language: 1
-Case reports: 1
-Systematic reviews: 10 -Not applicable results: 292
- Animal studies: 3
Full-text articles assessed for eligibility
(n =12)
-Number of implants lost not mentioned: 1 -No association between perforation and implant failure (n =2) Studies included in qualitative synthesis (n =10) Ide ntif ic ation Sc re ening El igi bi lity Inc lude d Duplicates removed (n =10) FILTER ED FILTER ED
15 Types of studies
The review included all human prospective and retrospective follow-up studies and clinical trials, cohort studies, case-control studies, on maxillary sinus floor elevation and Schneiderian membrane perforation published between January 2010 and February 2020.
Population
Subjects in the included studies, had atrophic posterior maxilla must have undergone maxillary sinus augmentation with either simultaneous or delayed implant placement.
Data items
Data were collected from the included articles and arranged in the following fields:
• “Author (Year)” – reported the author and year of publication.
• “Study Design” – described the type of the study.
• “Number of patients” – recorded the number of patients examined.
• “Number of implants” – reported the number of implants placed
• “Technique” – technique used to perform sinus augmentation
• “Surgical instrument” – type of instrument used during sinus augmentation
• “Number of perforations” – documented the number of Schneiderian membrane perforations that occurred during maxillary sinus augmentation procedure
• “Simultaneous / delayed implant placement” – Implants placed in one stage or two stages
• “Number of implants failed” – recorded number of implants lost
• “Bone graft” – described types of bone grafts used
• “Follow-up” – described the duration of the observed outcomes after maxillary sinus augmentation
16 Risk of bias assessment
Cochrane Collaboration’s tool for assessing risk of bias for the evaluation of the risk of bias was assessed [9].
The grades of bias were categorized as follows: low risk, if all the criteria were sufficed; moderate risk, when only one criterion was absent; high risk, if two or more criteria were missing; and unclear risk, if too few details were available to make a judgment of certain risk assessment.
Study selection
Article review and data extraction were conducted in accordance to PRISMA flow diagram (Figure 1). The preliminary electronic and hand search retrieved 490 citations, 10 of which were discarded as duplicates or not relevant articles. After titles and abstracts were reviewed, additional 462 articles were filtered as having not enough information regarding selected topic. 12 articles were identified as full-text articles, 10 of which were included in this review [10-19].
Study characteristics
Two prospective clinical studies [11, 16] and seven retrospective clinical trials [10, 12, 13-19] were included for the final review. A total of 1628 patients (3253 implants) were treated. The mean age of the patients was 56.5 years with the observation period ranging from 6 to 98 months. Three studies [11, 18-19] reported smoking status of the patients, ranging from 8.3% [11] to 47.3% [18]. Implants were installed either with lateral approach (n=3,139) [10, 11, 13-15, 17-19], or crestal (n=114) [12, 16]. In all the lateral approach studies, the majority of lateral window osteotomies were performed with rotary burs [10, 11, 13-14, 17-19], except the study in which Kerrison rongeur was used [15]. Crestal sinus lift was performed using osteotome according to Summers technique in all the crestal approach studies [12, 16]. The summarized individual study characteristics are described in Table 2.
Pre-operative and post-operative radiographs were orthopantomographs in five studies [10, 11, 12, 15, and 19], three studies used cone beam computed tomography (CBCT) [13, 17, and 18] and one study used computerized axial tomography [14]. Follow-up examinations were checked with panoramic [10,11,12,13,17,18], periapical [11,13,14,15,16,18] and CBCT [19] radiographs.
8 studies utilized grafting materials for maxillary sinus augmentation. Most commonly autografts [10, 13, 14] were used as well as other grafting materials, including xenografts [11, 15, 18],
17 allografts [17, 19]. There were more study groups using barrier membranes [10, 11, 13, 14, 15, 17, 18, 19], than study groups, without barrier membranes utilized to cover the grafted area [12, 16].
Risk of bias within studies
The risk of bias assessment for the included studies is summarized in Table 2. Summarizing the risk of bias for each study, most of the studies were classified as unclear risk because some information was not available in order to decide about of certain risk assessment.
18 Table 2. Risk of bias assessment
+=low risk ?= unclear risk -=high risk
Author/Year Random sequence generation (selection bias) Allocation concealment (selection bias) Blinding of participants and personnel (performance bias) Blinding of outcome assessment (detection bias) (patient-reported outcomes) Blinding of outcome assessment (detection bias) (Mortality) Incomplete outcome data addressed (attrition
bias), short–term outcomes (-6 weeks)
Incomplete outcome data addressed (attrition bias) Longer-term outcomes(>6 weeks) Selective reporting (reporting bias) Beck-Broichsitter et al., 2018 - ? - - + + - + Cha et al., 2012 - ? - - + + + + Ding et al., 2013 - ? - - + + + ? Ferreira et al., 2017 - ? - - + + + ? Froum et al., 2013 - ? - - + + + ? Kim et al., 2016 - ? - - + + + + Nooh 2013 - ? - - + + + ? Nolan et al., 2014 - ? - - + + + ? Park et al., 2019 a - ? - - + + + + Park et al., 2019 b - ? - - + + + +
19
Systemization and analysis of data
Table 3. Characteristics of included studies.
Author /Year
Study Design Number of
patients, implants Technique Surgical instrument Number of Schneiderian membrane perforations
Number of Implants lost Follow up Comments
Perforated maxillary sinus membrane Non perforated maxillary sinus membrane Beck-Broichsitt er et al., 2018 Retrospective cohort clinical study 63/175 Lateral window technique Round bur 41 1 0 2.69 (±2.03) years
Bio-Gide membrane was used to cover perforations and stitched with resorbable sutures. Implant survival was 98.9% in the perforation group analogized to 100% in the control group. Cha et al.,
2012 cohort clinical Prospective study
217/462 Lateral
window technique
Round bur 35 3 13 36-98
months Bio-Gide membrane and fibrin glue were used to repair the membrane perforations, the incidence of which did not have a significant negative consequence on implant survival and success. (p = 0.7162)
Ding et
al., 2013 Retrospective clinical study 42/51 Sinus Floor Osteotome Elevation
Osteotome 6 0 - 18 months
after loading
There was no use of a grafting material however no inflammation developed in patients, during observation period all implants succeeded.
Ferreira et
al., 2017 cohort clinical Retrospective study
745/1588 Lateral
window technique
Round bur 237 39 - 2 years
after loading
The survival rates for the implants placed under non-perforated sinus membranes (1065) was 97.7% and 97.1% for implants placed under perforated membranes (523), when comparing them difference was not statistically significant (p > 0.05).
Froum et al., 2013 Retrospective cohort clinical study 40/80 Lateral window technique
Round bur 15 0 2 6-8 months Implants placed under perforated sinus membranes had 100%
survival rate in comparison to implants placed under
non-perforated membranes which had 95.5% survival rate (χ2 = 0.326).
Kim et al.,
2016 Retrospective clinical study 41/99 window Lateral
technique
Kerrison
rongeur 41 0 - 2.1 years No failure was noted on the maxillary bone graft with implant placement, accomplished on patients with a perforated maxillary
sinus membrane recording 100% survival rate. Nooh
2013 clinical study Prospective 56/63 Sinus Floor Osteotome
Elevation
Osteotome 63 1 - 1 year after
loading 98.4% survival rate of implants placed under perforated maxillary sinus membranes was noted (1 out of 68 implants failed) after 1 year of observation period.
Nolan et
al., 2014 Retrospective clinical study 208/nm window Lateral technique
Round bur 150 17 7 1 year after
loading 11.3% of graft failures were noted in sinuses with perforated membranes as to 3.4% of grafts failure of sinuses with intact membranes (p = 0.0335) and same for implant failure (p = 0.0335). Park et al.,
2019 a Retrospective clinical study 207/613 window Lateral
technique
Round bur 73 24 - 11.76 years The hazard ratio of implant failure between the perforated
membrane group and the non-perforated group showed no significant statistical difference (p = 0.081).
Park et al.,
2019 b Retrospective clinical study 63/122 window Lateral
technique
Round bur 24 0 0 11.52
months
The bone graft height was stable over the follow-up period in both groups (p > 0.05). No implant failure was recorded.
20
RESULTS
In the study conducted by Beck-Broichsitter et al. [10] a total of 92 implants were inserted. Eleven implants were inserted simultaneously, whereas the remaining 81 implants were inserted in a second surgical operation. In the control group a total of 83 implants were inserted, of which 30 implants were inserted in a one-stage procedure, whereas remaining 53 implants in a two-stage procedure. There was no requirement of additional bone graft in the greater part of procedures (65.1%), concerning the control group, whereas 59.8% of surgical interventions required iliac crest in the perforation group. The initial bone level differed significantly (p = 0.05) between both groups with a median value of 5.69 mm in the study group and 3.87 mm in the control group. A Mann-Whitney-U-Wilcoxon test revealed no significant difference between bone level postoperatively (p = 0.7851), in follow-up (p = 0.2238), or for bone resorption (p = 0.9455). Regarding the height of augmented maxillary sinus floor postoperatively, a manifold comparison analysis revealed a considering difference between the groups (p = 0.2721). Fisher’s exact test displayed a statistically significant difference of proportions of one-stage versus two-stage procedures due to the presence of perforation (p = 0.0003) and a significantly higher trend for peri-implantitis in patients with perforation (p = 0.0004). In this study residual bone height between 1 to 3 mm was not encouraging for immediate implant insertion. Implant insertion was simultaneously performed only if the approximated residual bone quality assured high primary stability.
In the research operated by Cha et al. [11] implant success rate was evaluated according to the consecutive criteria proposed by Albrektsson and colleagues [20]: (1) omission of constant pain; (2) absence of peri-implant contamination with suppuration; (3) absence of implant mobility; (4) lack of constant peri-implant radiolucency; and (5) peri-implant bone resorption <1.5 mm in the first year of function and <0.2 mm in the consequent years. Implant survival was defined as functional implants that adhered to the parameters.
A sum of 217 lifts and 462 implants were placed synchronously in 161 patients. Out of 161 patients, 56 patients received bilateral sinus lifts and 105 patients had unilateral sinus lifts and implant installation. Implants were installed from the first premolar to second molar area (78.2% molars). A total of 35 of 217 (16.13%) sinus membranes were perforated during surgery. Membrane perforations were restored with collagen membrane and fibrin glue. Bone grafts and implants were installed as planned without delay in any case. A total of 68 of 462 (14.72%) implants were placed in perforated sinuses and 3 (4.41%) implants of these failed. The chi-square test with Fisher’s exact test performed in this study affirmed no statistically significant difference in success rate between the implants placed in perforated and non-perforated sinuses (p = 0.7162).
21 In the retrospective study of Ferreira et al. [13] the perforated sinuses amount to 237, amidst of which 48 sinuses had large perforations, 67 sinuses had medium perforations and 122 sinuses had small perforations. The perforation size was classified correspondingly. Small perforation was considered ≤5 mm, medium between >5 mm and <10 mm, and large ≥10 mm. Out of 266 implants placed on sinuses with small perforations, 6 failed. For medium perforations, there were 4 failures out of 150 implants placed. In large perforations there were 5 failures out of 107 implants placed. Difference between survival rates of implants in different perforation sizes was not significant (p > 0.5). The difference among implants placed on non-perforated sinuses and perforated sinuses was not statistically significant (p > 0.5).
In the study directed by Ding et al., [12] maxillary sinus augmentations were performed with the elevation with osteotomes (OSFE) technique, out of which 6 maxillary sinus membrane perforations were identified using depth gauge, and 6 implants were installed. A total of 4 detected perforations out of 51 sites treated with the OSFE represent a rate of 11.8%. Most of the implants in intact sinuses exhibited peri-implant bone formation, and 3 of 6 implants in perforated sinuses exhibited peri-implant bone formation too. Nevertheless, the other 3 of 6 implants in perforated sinuses showed no bone formation. No signs of peri-implantitis were found during 1.5-year follow-up period. These inputs suggest a 100% survival rate of implant in both intact and perforated sinuses.
Perforation complications were reported in 15 sinuses (37%) in the Froum et al. [14] study. All the perforations were labeled as small-to-medium size, less 10 mm in diameter. The implant survival rate in perforated sinuses was 100% (35 of 35) compared with the non-perforated sinuses with 95.5% (43 of 45). There was no statistical significance in implant failure between non-perforated sinuses and implant failure in the perforated group (χ2 = 0.326) when performing the chi-squared
test.
Nooh’s, 2013 study investigated the effects of an intentional penetration of the Schneiderian membrane. The perforation was made by 2 mm twist drill. During the 1-year follow-up, patients were assessed clinically and radiographically. A survival rate of 98.4% was recorded since one implant was determined not stable. This implant failure transpired before the second stage therefore it was removed before restoration.
All implants included in the study by Kim et al. [15] displayed 100% survival considering no failure of implant was reported. Implants were fixed simultaneously with the maxillary sinus floor augmentation if the residual bone height was >2 mm, and if primary stability of the implant was clinically accepted by the surgeon according to the mobility of the implant fixture. Alternatively, the implant was installed 4 months after the maxillary sinus augmentation procedure. 99 implants were installed in 41 patients whose sinus membranes were perforated during lateral approach.
22 Repair of the perforated sinus membranes was done with a resorbable collagen membrane. In 37 patients implant placements were performed simultaneously with sinus bone grafting, whereas delayed placements were executed in 4 patients. The average residual bone height was 3.4 ± 2.0 mm in cases of simultaneous implant placement and 0.6 ± 0.9 mm in cases of delayed placement. 150 sinuses were penetrated during sinus floor elevation which constitutes the 41.8% rate of perforation in the Nolan et al. [17] research. The overall sinus graft failure in this study was 6.7%. This study demonstrated a greater, however not statistically significant incidence of failure both of grafts and implants (p = 0.0335), granted that membrane was perforated during elevation. Maxillary sinus graft failures developed in 11.3% of maxillary sinuses with perforated membranes in comparison to 3.4% of maxillary sinuses with unperforated membranes.
According to the study executed by Park et al. [18], out of 207 patients in 73 patients Schneiderian membrane perforation occurred. However, there was no significant difference between the maxillary sinus membranes perforated group and the non-perforated group in implant failure rates (p = 0.081).
Another retrospective study designed by Park et al. [19] included 63 patients. 24 out of 65 sinuses were penetrated during this study constituting the rate of perforation to 39%. In the course of follow-up period no case of implant failure was documented irrespectively to the occurrence of maxillary sinus membrane perforation.
23
DISCUSSION
In this review the association between maxillary sinus membrane perforation during sinus augmentation procedure and dental implant failure rate was examined. Maxillary sinus floor elevation is frequently employed in situations where alveolar bone resorption induced inadequate bone height for the installation of dental implants [21]. Numerous maxillary sinus augmentation techniques have been used with remarkable success rates aspiring to develop these sites for implant placement [22].
Perforations of the Schneiderian membrane are relatively frequent. It is possible for the membrane to be perforated during osteotomy preparation or membrane elevation. Anatomical maxillary sinus variations may increase the risk of complications related to maxillary sinus floor augmentation. Anatomical changes of the maxillary sinus floor such as convolutions and root-shape expressions, commonly observed in patients with recent tooth extraction, may render the procedure of elevating the maxillary sinus membrane more challenging [21]. This is also evident by the study performed by Beck-Broichsitter et al. [10] where they found an association between tissue qualities, either scarring because of preceding procedures or local inflammation, and a greater prospect of Schneiderian membrane perforation with anatomical alterations, such as sinus septa or fine, susceptible membrane textures. A few studies have recommended contraindication of sinus floor elevation in patients with anatomical variations such as septa or mucosal swellings [23]. Also noticeable in this study was the appearance of peri-implantitis detected more frequently in patients who experienced a procedure with an intraoperative perforation.
At the moment it is generally accepted that following initial bone remodeling after an augmentation procedure followed by a dental implantation, bone loss within the following 3 years with implants in the interproximal space should be less than 0.5 mm in radiographic evaluations [24]. Beck-Broichsitter et al. [10] identified that there was no influence of bone graft origin or postoperative complications in patients with perforation of the Schneiderian membrane, analogous to a study by Moreno Vazquez et al., [25], which also did not find a correlation between complications, graft failure, and membrane perforation, evaluating 8 years postoperatively. This is consistent with this systematic review as well since no further complications or adverse effects on implant survival were noted.
The surgical management of a membrane perforation is possible to influence the overall postoperative outcome and complications. Even though, the sinus lifting procedure has been established for many years now, there are no evidence-based guidelines for how to proceed with perforation closure or implications to interrupt the procedure.
24 As per day, most existing studies recommend that all perforations smaller in size should be sealed with membranes like collagen, demineralized laminal bone or fibrin glue. If there is a case of larger of perforation, it is advised to use resorbable sutures when complete closure of the perforation is possible [26], however it has not been proved to be greater since the envelopment of larger perforations with membranes alone demonstrated effectiveness [27].
With sinus perforations exceeding 15 mm, gradual bioresorbable collagen membrane and platelet rich plasma should be employed as suggested by Pikos [28]; that operates as an adhesive to restore both partial and complete maxillary sinus membrane perforations.
An assortment of bone graft materials may be used for maxillary sinus augmentation including autogenous bone from intraoral and extraoral sites, no graft, mineralized or demineralized freeze-dried allogenic bone, xenogenic bone, alloplastic, growth factors, or combination of materials [29, 30]. Cha et al. [11] used xenograft alone to augment the maxillary sinus floor. According to them xenografts provide the following advantages: no additional surgical site for bone harvesting, reducing surgical time, and lower resorption rate.
On another note, in the study conducted by Park et al. [18] a higher perforation rate was associated with male gender, this result was consisted to previous studies which reported that implant failure was more prevalent in males than females [31], and the existence of sinus pathoses. It was concluded that, the presence of preoperative sinus pathology was associated with a significantly higher rate of membrane perforation. The Schneiderian membrane was substantially thicker in patients with perforation in comparison to patients with an intact sinus membrane. The thickness of the Schneiderian membrane was decreased significantly after the sinus lift procedure [18]. However, there is no scientific confirmation to date to conclude whether the effect is just ephemeral or persistent in nature. In addition, the frequency of smoking and the presence of systemic diseases in patients with or without sinus perforation were significant for implant failure [18].
A few limitations can be attributed to this systematic review. The studies used were observational studies rather than RCTs, which may have an increased risk of bias. Furthermore, the majority of studies were retrospective and due to the essence of these studies a standardized protocol was not pursued. In the instance of sinus membrane perforations, the approaches were dissimilar, a different variety of graft materials were used in different studies.
25
CONCLUSIONS
Within the limits of the present study the following conclusion can be reached:
Most of the investigated studies reported that, the occurrence of a perforated maxillary sinus membrane did not have a significant effect on implant failure rate compared to intact sinus membranes during maxillary sinus augmentation procedure.
The results of the current study disprove the initial hypothesis. Coherent and rational surgical assessment and treatment modalities avoid complications arising from maxillary sinus membrane perforation and do not have a significant influence on implant survival.
26
CLINICAL RELEVANCE
According to the findings of our study perforation of the maxillary sinus membrane does not have an impact on implant survival. Even though no guidelines or an exact protocol of how to manage this perforation exist, a few of the preferred treatment modalities include placing collagen membrane, fibrin sealants or suturing additionally with resorbable sutures. Nevertheless, in some instances when perforation is small when left untreated it does not further affect implant survival. When surgeons are experienced with how to respond and treat the occurrence of a sinus membrane perforation, its incidence (within reasonable size) should not be considered as an indication to disrupt the maxillary sinus augmentation surgery.
RECOMMENDATIONS FOR FURTHER RESEARCH
Further studies level of evidence are needed to further assess the relationship between maxillary sinus membrane of a high perforation and implant failure rate and to evaluate the influence of other variables, such as the amount of residual crestal bone in the posterior maxilla as well as the factor of immediate loading, on the survival of implants installed in the grafted maxillary sinus.
27
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