Ignite Creation Date:
2024-05-05 @ 10:58 PM
Last Modification Date:
2024-10-26 @ 10:27 AM
Study NCT ID:
NCT01229995
Status:
UNKNOWN
Last Update Posted:
2010-10-28
First Post:
2010-10-27
Brief Title:
Randomized Controlled Clinical Trial of CADCAM and Conventionally Fabricated Singl Implant Abutments
Sponsor:
Harvard School of Dental Medicine
Organization:
Harvard School of Dental Medicine
Study Overview
Official Title:
A Comparison of Zirconia CADCAM and Conventionally Fabricated Single Implant Abutments and Restorations in the Esthetic Zone a Randomized Controlled Clinical Trial
Status:
UNKNOWN
Status Verified Date:
2010-10
Last Known Status:
ACTIVE_NOT_RECRUITING
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
CADCAM technology has been introduced to the field of implant dentistry in the beginning of 1990s Priest 2005 Since their introduction the use of CADCAM technology in the production of dental implant restorations has been rapidly expanding However little evidence is currently present supporting its clinical viability Henriksson 2003 Canullo 2007
Therefore the suggested prospective randomized study includes bone level placed Straumann implants restored with transmucosal elements and crowns fabricated using either CADCAM Etkon technology Zirconia abutment and ceramic crown or a conventional technique Crossfit titanium abutment and a ceramometal crown
The aim of this randomized controlled clinical trial is to examine single-tooth implant restorations in the esthetic zone An esthetic area is defined as any area that is visible in the patients full smile 3rd ITI consensus conference 2004 The rehabilitations will be fabricated using two different techniques Zirconia CADCAM ZCC implant restorations tests will be compared to Titanium conventionally-fabricated TCF implant restorations controls using reproducible esthetic objectivesubjective and biologic parameters
This in vivo study is a randomized study with two groups of 15 patients with one implant each for a total of 30 patients and 30 implants The implants will be examined for successful tissue integration according to the criteria of success Buser et al 1990 at every recall visit
In addition the following parameters will be evaluated for each restoration
Esthetic A Objective PESWES Score Belser et al 2009 from 11 digital photograph study casts and spectrophotometric measurements and B Subjective VAS questionnaire for patients and VAS questionnaire from experts
Biologic mPI mB simplified GI microbial sample periapical radiograph for DIB and width of keratinized facial mucosa
Finally an evaluation of the mechanical biologic and technical complications will be performed at every recall visit Mechanical complications would be defined as those complications that involve the prosthesis such as abutment screw loosening fracture of the veneer material fracture of the crown framework abutment screw fractures and implant fractures The category of biologic complications will include those complications that involve the soft tissues eg fistula suppuration bleeding gingival inflammation and soft tissue dehiscence Technical complications are defined as those related to restorative components and crowns eg crown emergence profile abutment and crown fit screw loosening ceramic fracture
Therefore the suggested prospective randomized study includes bone level placed Straumann implants restored with transmucosal elements and crowns fabricated using either CADCAM Etkon technology Zirconia abutment and ceramic crown or a conventional technique Crossfit titanium abutment and a ceramometal crown
The aim of this randomized controlled clinical trial is to examine single-tooth implant restorations in the esthetic zone An esthetic area is defined as any area that is visible in the patients full smile 3rd ITI consensus conference 2004 The rehabilitations will be fabricated using two different techniques Zirconia CADCAM ZCC implant restorations tests will be compared to Titanium conventionally-fabricated TCF implant restorations controls using reproducible esthetic objectivesubjective and biologic parameters
This in vivo study is a randomized study with two groups of 15 patients with one implant each for a total of 30 patients and 30 implants The implants will be examined for successful tissue integration according to the criteria of success Buser et al 1990 at every recall visit
In addition the following parameters will be evaluated for each restoration
Esthetic A Objective PESWES Score Belser et al 2009 from 11 digital photograph study casts and spectrophotometric measurements and B Subjective VAS questionnaire for patients and VAS questionnaire from experts
Biologic mPI mB simplified GI microbial sample periapical radiograph for DIB and width of keratinized facial mucosa
Finally an evaluation of the mechanical biologic and technical complications will be performed at every recall visit Mechanical complications would be defined as those complications that involve the prosthesis such as abutment screw loosening fracture of the veneer material fracture of the crown framework abutment screw fractures and implant fractures The category of biologic complications will include those complications that involve the soft tissues eg fistula suppuration bleeding gingival inflammation and soft tissue dehiscence Technical complications are defined as those related to restorative components and crowns eg crown emergence profile abutment and crown fit screw loosening ceramic fracture
Detailed Description:
Introduction
Long-term prospective studies demonstrate a high success rate of Straumann implants in partially or fully edentulous patients both with early and conventional loading Salvi et al 2004 Lambrecht et al 2003 Cochran et al 2002 Weber et al 2000 Buser et al 1997 Before the introduction of CADCAM technology to the field of implant dentistry in the beginning of 1990s Priest 2005 the available approach for restoring single dental implants was either with stock or cast custom abutments and a ceramo-metal crowns In spite of the satisfactory results that this conventional treatment approach has achieved several disadvantages have been recognized First non tooth-colored abutments possess the problem of bluish appearance of overlying tissue in cases of thin gingival biotype Barclay et al 1996 Prestipino and Ingber 1996 Second with stock abutments ideal emergence profile can not be achieved Daftary 1997 a disadvantage that was reduced with the use of custom abutments However custom abutments present other disadvantages including possible imprecision of fit due to inaccuracies associated with impression waxing investing and casting procedures and the negative effect of the gold alloy on the peri-implant mucosal barrier as demonstrated by Abrahamsson in 1998 Abrahamsson et al 1998
The introduction of CADCAM technology to implant dentistry was meant to provide higher quality restorations Since its introduction the use of this technology in the production of implant ceramic frameworks and crowns especially in esthetic regions has been rapidly expanding because of the promising esthetic biologic and mechanical properties Alumina as well as Zirconia abutments are characterized by good tissue compatibility Abrahamsson et al 1998 In a study by Barclay et al in 1996 it was found that plaque accumulation scores for ceramic-coated transmucosal elements were significantly lower than those recorded in titanium transmucosal elements Barclay et al 1996 These results suggest that the further development of a ceramic implant transmucosal collar may assist plaque control at the soft tissue-implant interface and may favorably influence the tissues in this region Barclay et al 1996 Other studies documented no significant differences in plaque accumulation and microbial colonization between titanium and ceramic abutment samples Andersson et al 2003 Rasperini et al 1998 The bacterial colonization of Zirconia ceramic surfaces was recently studied in vitro and in vivo Rimondini et al 2002 The authors found that overall Zirconia ceramic surfaces developed for implant abutments accumulate fewer bacteria than commercially pure titanium and may therefore be considered as a promising material for abutment manufacturing Rimondini et al 2002 A comparison of the recorded superficial soft tissue responses to titanium and ceramic surfaces of transmucosal elements of implants revealed no significant differences between both groups Barclay et al 1996 Andersson et al 2001 Almost no marginal bone loss was recorded indicating a stable bone situation both at ceramic and titatium abutments on single-tooth implants Andersson et al 2001 However it seems to be that the peri-implant soft tissues adjacent to titanium and ceramic surfaces may differ in features that are not apparent when routine clinical parameters are used Barclay et al 1996
Because of their specific mechanical properties all-ceramic restorations demonstrate a lower fracture resistance than ceramic restorations supported by metal substructures The ceramic abutments on implants are more sensitive to fracture and to handling procedures than the titanium abutments Andersson et al 2001 However advances have been made in the fabrication of high-strength all-ceramic abutments for anterior implants Yildirim et al 2003 The hardness of the Zirconium ceramic also allows it to undergo conventional prophylaxis with ultrasonic scalers without alteration of its surface quality of abutment Marzouk 1996 Moreover Zirconia has a flexural strength and fracture toughness almost twice as high as alumina Glauser et al 2004 Yildirim et al 2003
Currently very limited number of clinical studies is present supporting the clinical viability of CADCAM ceramic restorations Henriksson 2003 Canullo 2007 and no reports were found on the performance of CADCAM ceramic implant restorations in comparison to conventional implant restorations
Objective
The aim of this randomized controlled clinical trial is to examine single-tooth implant abutments and restorations in the esthetic zone Restorations will be fabricated using two different techniques Zirconia CADCAM ZCC implant abutments and restorations will be compared to conventional prefabricated Titanium TCF implant abutments and porcelain-fused-to-metal restorations using reproducible aesthetic objectivesubjective and biologic parameters
Hypothesis
The hypothesis of this investigation is that ZCC implant abutmentsrestorations test group will achieve better biologic and esthetic outcomes when compared with TCF types control group The null hypothesis is defined as follows ZCC implant abutmentsrestorations and TCF implant restorations are indistinguishable when biologic and esthetic outcomes are compared
Clinical Significance
CADCAM technology has been involved in the fabrication of dental abutments and restoration for the purpose of improving the biologic and esthetic results This assumption has been formulated primarily from subjective interpretations as objective assessments from randomized controlled trials are sparse at best This study will be significant for clinical dentistry in that it will create evidence on the clinical long-term performance of Zirconium CADCAM abutments and ceramic crowns compared to stock titanium abutments and porcelain-fused-to-metal restorations using subjective and objective evaluation parameters that will be statistically compared
Materials and Methods
Patients with an indication for an implant supported single tooth restoration in the esthetic zone will be included in the study according to the following criteria
Inclusion Criteria
General
1 Age 21 years
2 Absence of relevant medical conditions
3 Absence of periodontal diseases
4 The opposing dentition must be natural teeth or fixed not removable restorations on teeth or implants
5 Availability for 5-year follow-up
Local
1 One missing tooth in the esthetic zone An esthetic area is defined as any area that is visible in the patients full smile 3rd ITI consensus conference 2004
2 Presence of two intact adjacent teeth which are either non-restored or with minor restorations small composite restorations
3 Adequate native bone to achieve primary stability
4 Adequate band of keratinized mucosa at least 2mm
5 Full Mouth Plaque Scores FMPS and Full Mouth Bleeding Scores FMBS 25
Exclusion criteria
General
1 Heavy smokers more than 10 cigarettesday
2 Presence of conditions requiring chronic prophylactic use of antibiotics
3 Medical conditions requiring prolonged use of steroids
4 History of radiation therapy to the head or neck or history of chemotherapy
5 Physical handicaps that would interfere with the ability to perform adequate oral hygiene
6 Patients with inadequate oral hygiene
Local
1 Adjacent implant
2 Presence of periapical radiolucencies at the adjacent teeth
3 Missing adjacent teeth
4 Local inflammation including untreated periodontitis
5 Persistent intraoral infections
6 Untreated mucosal diseases
Subject population Patients will be recruited from the patient pool of the Teaching and Faculty Practice at the Harvard School of Dental Medicine A 12-month period will be allowed to enroll the patients in this study The mean treatment outcome will be compared between the two randomized patient groups allowing for detection of the smallest clinically important differences between these means TheSealedEnvelope- httpwwwthesealedenvelopecom powerphp
Patient entry informed consent patient registration randomization and blinding An informed consent approved by the Harvard Medical SchoolHarvard School of Dental Medicine Committee on Human Studies will be obtained for all subjects to be entered in this study Its conduct will adhere to the principles outlined by the Office for Research Subject Protection of the Harvard Medical School Harvard School of Dental Medicine Each subject will be randomly assigned to one of the two treatment options A random permuted block approach will be used to allocate patients into one of the treatment groups A sealed envelope containing the treatment group control or test group will be assigned to each patient Subsequently and according to the assigned treatment a ZCC restoration test group or a TCF ceramo-metal control group will be fabricated and delivered to the clinician
For subjective evaluation the trial design will be on a double blinding level which means that neither patients nor expert clinicians will know which treatment the patients are randomized to This can be achieved by concealing allocation information from patients and by using expert clinicians who are otherwise not involved in the patients care to assess treatment difficulties and outcomes without knowing their treatment group
Treatment groups
30 patients will be randomly allocated to control or test group presented in Table 1
Group n 30 patients Implant Abutment Crown Loading Test group n15 ZCC BL Straumann Etkon Zirconia Cement-retained Etkon Zirconia 6-8 weeks control group n15 TCF BL Straumann Crossfit titanium Cement-retained PFM 6-8 weeks
Evaluation Parameters and time schedule
Patients will be evaluated for esthetic objective and subjective parameters and biologic parameters as well as the success criteria through out the study period The baseline measurements are defined as the measurements taken during the healing period after insertion of bone level implant
During the healing period after insertion of a Straumann Bone Level implant following standard surgical procedures patients will use removable provisional prostheses
The implants will be examined for successful tissue integration according to the criteria of success Buser et al 1990 at every recall
Criteria of success
1 Absence of persistent subjective complaints such as pain foreign body sensation andor dysaesthesia
2 Absence of a recurrent peri-implant infection with suppuration
3 Absence of mobility
4 Absence of a continuous radiolucency around the implant
Esthetic parameters
Objective parameters
Standardized intra-oral digital photograph 11 magnification An intra-oral photograph will be taken positioning the plane of the camera body parallel to the vestibular face of the teeth adjacent to the single edentulous gap Figure 1
Papilla Height Distance between the mesial and distal papilla and the zenith of the mid-facial gingival margin of the adjacent teeth The distance from the most coronal part of the mesial and distal papillae to the zenith of adjacent teeth will be measured from study casts and digital photographs Figure 2
Buccal gingival margin measurement Distance between the mid-facial gingival margin and the incisal edge of adjacent teeth The distance from the zenith of adjacent teeth to the most coronal part of the incisal edge will be measured from study casts and digital photographs This measurement will serve to determine the buccal gingival recessiongrowth when compared with further measurements It will be recorded as 0 at baseline Figure 3
Study cast
Spectrophotometer recording at adjacent teeth A spectrophotometer Crystaleye Olympus Japan will be used to select and digitally record the shade for each adjacent tooth The sterilizable adapter of the spectrophotometers intra-oral camera will be positioned on the alveolar process over the respective adjacent tooth Once the resulting video image of the tooth is centered in an orthoradial way in the measuring square depicted on the computer screen the spectrophotometric data will be recorded three consecutive times for each tooth This data will be later compared with records obtained from final crowns by repeating the spectrophotometer measurement over the control and test group restorations Figure 4
Buccal periimplant mucosa margin Distance between mid-facial gingival margin and incisal edge of the implant restoration At implant crown insertion the distance from the zenith of the implant restoration to the most coronal part of the incisal edge will be measured from study casts and digital photographs This measurement will serve to determine the buccal gingival recessiongrowth when compared with further measurements It will be recorded as 0 at the implant crown insertion Figure 5
Subjective parameters
1 Visual Analogue Scale VAS of patients judgment on
At baseline detriment of hisher esthetic appearance and respective expectations
At crown insertion
Overall treatment satisfaction
Accomplishment of initial expectations
At 1 6 months 1 3 and 5 year follow up
Overall treatment satisfaction
Impact on self-esteem
Functionality
2 Visual Analogue Scale VAS of 3 expert clinicians judgments on the case difficulty
Parameters Follow-up time schedule Baseline At insertion 1 month 6 months 1 year 3 years 5 years
Esthetic
Objective
1 11 digital photograph
2 Papilla height
3 Buccal gingival margin
4 Study cast
5 Spectrophotometer
6 Buccal periimplant mucosa margin
Subjective
1 VAS questionnaire for patients
2 VASquestionnaire from experts
Biologic parameters
1 mPI Modified plaque index Mombelli et al 1987 for evaluation of oral hygiene standard 0 No detection of plaque 1 Plaque only recognized by running a probe across the smooth marginal surface of the implant 2 Plaque can be seen by the naked eye 3 Abundance of soft material
2 mBI Modified sulcus bleeding index mBI Mombelli et al 1987 0 No bleeding when a periodontal probe is passed a long the gingival margin adjacent to the implant 1 Isolated bleeding spots visible 2 Blood forms a confluent red line on margin 3 Heavy or profuse bleeding
3 simplified GI Simplified Gingival Index Apse et al 1991 0 Normal mucosa 1 Minimal inflammation with color change and minor edema 2 Moderate inflammation with redness edema and glazing 3 Severe inflammation wit redness edema ulceration and spontaneous bleeding without probing
4 Microbiological sample Microbial samples from a tooth in the same sextant as the implant and from the implant healing cap prior to its initial removal at the start of the restorative procedures will be obtained Additional samples will be taken at 1month 6 12 36 and 60 months after the insertion of the restoration The samples will be analysed for P gingivalis T forsythia B forsythus Tdenticola F nucleatum P micra P micros P nigrescens P intermedia C rectus C gracilis E nodatum and S constellatus Quirynen et al 2002 Keller et al 1998 Conrad et al 1996 Sample analysis will be performed at the Forsyth Institute Boston MA on a contractual basis Samples will be identified only by their number for this purpose No patient identifying data will be revealed The correlation between the periimplant microflora before and after loading within the same subject as well as potential differences in quantity and composition of the microflora of ZCC and TCF implant abutments and restorations will be analysed
5 Standardized periapical radiograph to assess DIB values Standardized peri-apical long cone parallel radiographs of the implant Harris et al 2002 will be taken For standardization of radiographs a film holder will be attached to a custom-made bite splint This same device will be used during the whole study for radiographic records From these radiographs bone resorption will be measured as distance from the implant shoulder to first bone-to-implant contact DIB Figure 6
6 Width of keratinized facial mucosa
Parameters Follow-up Time schedule Baseline Crown Insertion 1 mos 6 mos 1 year 3 years 5 years
Biologic
1 mPI modified Plaque Index
2 mBI modified sulcus Bleeding Index
3 simplified GI Gingival Index
4 microbiological sample
5 PA Periapical X-ray for DIB
6 Width of keratinized facial mucosa
D Mechanical Biologic and Technical complications An evaluation of the mechanical biologic and technical complications will be performed at every recall visit Mechanical complications would be defined as all those complications that involve the prosthesis such as abutment screw loosening fracture of the veneer material fracture of the crown framework abutment screw fractures and implant fractures The category of biologic complications will include the complications that involve the soft tissues ex fistulas suppuration bleeding gingival inflammation and soft tissue dehiscence Technical complications would be defined as those complications that are related to lab procedures and fabricating techniques ex abutment and crown emergence profile abutment and crown fit
Complications Follow-up Time Schedule Baseline At insertion 1 mo 6 mos 1 year 3 years 5 years
Mechanical
1 Abutment screw loosening
2 Fracture of a veneer material
3 Fracture of the crown framework
4 Fractures of abutment screws
5 Fractures implants
Biologic
1 Fistulas
2 Suppuration
3 Bleeding
4 Gingival inflammation
5 Soft tissue dehiscence
Technical
1 Abutment emergence profile
2 Crown emergence profile
3 Abutment fit
4 Crown fit
Statistical Analysis After data collection and completion of the investigation a one-way analysis of variance ANOVA will be used to compare the mean values of all objective and subjective parameters Their variance will be broken down into two components a between groups component control group vs test group at baseline crown insertion and each follow-up period and b within group component at baseline crown insertion and each follow-up period A multiple LSD range test confidence level 95 will be applied to determine which means differ statistically from each other
Timetable June 2009 beginning of the study May 2010 deadline for patients entry and allocation August 2010 deadline for data collection of baseline and crown insertion measurements September 2010 deadline for data collection of 1-month follow up measurements February 2011 deadline for data collection of 6-month follow up measurements August 2011 deadline for data collection of 12-month follow up measurements August 2012 deadline for data collection of 24-month follow up measurements August 2013 deadline for data collection of 36-month follow up measurements August 2014 deadline for data collection of 48th month follow up measurements August 2015 deadline for data collection of 60th month follow up measurements February 2016 deadline for final publication of data
References
Abrahamsson I Berglundh T Glantz PO Lindhe J The mucosal attachment at different abutments An experimental study in dogs J Clin Periodontol 1998259721-7
Andersson B Glauser R Maglione M Taylor A Ceramic implant abutments for short-span FPDs a prospective 5-year multicenter study Int J Prosthodont 2003166640-6
Andersson B Taylor A Lang BR Scheller H Scharer P Sorensen JA Tarnow D Alumina ceramic implant abutments used for single-tooth replacement a prospective 1- to 3-year multicenter study Int J Prosthodont 2001145432-8
Barclay CW Last KS Williams R The clinical assessment of a ceramic-coated transmucosal dental implant collar Int J Prosthodont 199695466-72
Belser UC Gruetter L Vailati F Bornstein MM Weber HP Buser D Outcome evaluation of early placed maxillary anterior single-tooth Implants using objective esthetic criteria
a cross-sectional retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores J Periodontol 2009 80 140-151
Buser D Mericske-Stern R Bernard JP Behnecke A Behnecke N Hirt HP Belser UC Lang NP Long-term evaluation of non-submerged ITI implants Part 1 8-year life table analysis of a prospective multi-center study with 2359 implants Clin Oral Implants Res 199783161-72
Canullo L Clinical outcome study of customized zirconia abutments for single-implant restorations Int J Prosthodont 2007 205 p 489-93
Cochran DL Buser D ten Bruggenkate CM Weingart D Taylor TM Bernard JP Peters F Simpson JPThe use of reduced healing times on ITI implants with a sandblasted and acid-etched SLA surface early results from clinical trials on ITI SLA implants Clin Oral Implants Res 2002132144-53
Daftary F Dentoalveolar morphology evaluation of natural root form versus cylindrical implant fixtures Pract Periodont aesthet Dent 1997 9469
Glauser R Sailer I Wohlwend A Studer S Schibli M Scharer P Experimental zirconia abutments for implant-supported single-tooth restorations in esthetically demanding regions 4-year results of a prospective clinical study Int J Prosthodont 2004173285-90
Henriksson K and T Jemt Evaluation of custom-made procera ceramic abutments for single-implant tooth replacement a prospective 1-year follow-up study Int J Prosthodont 2003 166 p 626-30
Lambrecht JT Filippi A Kunzel AR Schiel HJ Long-term evaluation of submerged and nonsubmerged ITI solid-screw titanium implants a 10-year life table analysis of 468 implants Int J Oral Maxillofac Implants 2003186826-34
Marzouk J Two applications of transmucosal milled ceramic in implantology preliminary clinical examples Quintessence Int 1996278533-47
Prestipino V Ingber A All-ceramic implant abutments esthetic indications J Esthet Dent 199686255-62
Priest G Virtual-designed and computer-milled implant abutments J Oral Maxillofac Surg 2005 6322-32
Rasperini G Maglione M Cocconcelli P Simion M In vivo early plaque formation on pure titanium and ceramic abutments a comparative microbiological and SEM analysis Clin Oral Implants Res 199896357-64
Rimondini L Cerroni L Carrassi A Torricelli P Bacterial colonization of zirconia ceramic surfaces an in vitro and in vivo study Int J Oral Maxillofac Implants 2002176793-8
Salvi GE Gallini G Lang NP Early loading 2 or 6 weeks of sandblasted and acid-etched SLA ITI implants in the posterior mandible A 1-year randomized controlled clinical trial Clin Oral Implants Res 2004152142-9
Weber HP Crohin CC Fiorellini JP A 5-year prospective clinical and radiographic study of non-submerged dental implants Clin Oral Implants Res 2000112144-53
Yildirim M Fischer H Marx R Edelhoff D In vivo fracture resistance of implant-supported all-ceramic restorations J Prosthet Dent 2003904325-31
Long-term prospective studies demonstrate a high success rate of Straumann implants in partially or fully edentulous patients both with early and conventional loading Salvi et al 2004 Lambrecht et al 2003 Cochran et al 2002 Weber et al 2000 Buser et al 1997 Before the introduction of CADCAM technology to the field of implant dentistry in the beginning of 1990s Priest 2005 the available approach for restoring single dental implants was either with stock or cast custom abutments and a ceramo-metal crowns In spite of the satisfactory results that this conventional treatment approach has achieved several disadvantages have been recognized First non tooth-colored abutments possess the problem of bluish appearance of overlying tissue in cases of thin gingival biotype Barclay et al 1996 Prestipino and Ingber 1996 Second with stock abutments ideal emergence profile can not be achieved Daftary 1997 a disadvantage that was reduced with the use of custom abutments However custom abutments present other disadvantages including possible imprecision of fit due to inaccuracies associated with impression waxing investing and casting procedures and the negative effect of the gold alloy on the peri-implant mucosal barrier as demonstrated by Abrahamsson in 1998 Abrahamsson et al 1998
The introduction of CADCAM technology to implant dentistry was meant to provide higher quality restorations Since its introduction the use of this technology in the production of implant ceramic frameworks and crowns especially in esthetic regions has been rapidly expanding because of the promising esthetic biologic and mechanical properties Alumina as well as Zirconia abutments are characterized by good tissue compatibility Abrahamsson et al 1998 In a study by Barclay et al in 1996 it was found that plaque accumulation scores for ceramic-coated transmucosal elements were significantly lower than those recorded in titanium transmucosal elements Barclay et al 1996 These results suggest that the further development of a ceramic implant transmucosal collar may assist plaque control at the soft tissue-implant interface and may favorably influence the tissues in this region Barclay et al 1996 Other studies documented no significant differences in plaque accumulation and microbial colonization between titanium and ceramic abutment samples Andersson et al 2003 Rasperini et al 1998 The bacterial colonization of Zirconia ceramic surfaces was recently studied in vitro and in vivo Rimondini et al 2002 The authors found that overall Zirconia ceramic surfaces developed for implant abutments accumulate fewer bacteria than commercially pure titanium and may therefore be considered as a promising material for abutment manufacturing Rimondini et al 2002 A comparison of the recorded superficial soft tissue responses to titanium and ceramic surfaces of transmucosal elements of implants revealed no significant differences between both groups Barclay et al 1996 Andersson et al 2001 Almost no marginal bone loss was recorded indicating a stable bone situation both at ceramic and titatium abutments on single-tooth implants Andersson et al 2001 However it seems to be that the peri-implant soft tissues adjacent to titanium and ceramic surfaces may differ in features that are not apparent when routine clinical parameters are used Barclay et al 1996
Because of their specific mechanical properties all-ceramic restorations demonstrate a lower fracture resistance than ceramic restorations supported by metal substructures The ceramic abutments on implants are more sensitive to fracture and to handling procedures than the titanium abutments Andersson et al 2001 However advances have been made in the fabrication of high-strength all-ceramic abutments for anterior implants Yildirim et al 2003 The hardness of the Zirconium ceramic also allows it to undergo conventional prophylaxis with ultrasonic scalers without alteration of its surface quality of abutment Marzouk 1996 Moreover Zirconia has a flexural strength and fracture toughness almost twice as high as alumina Glauser et al 2004 Yildirim et al 2003
Currently very limited number of clinical studies is present supporting the clinical viability of CADCAM ceramic restorations Henriksson 2003 Canullo 2007 and no reports were found on the performance of CADCAM ceramic implant restorations in comparison to conventional implant restorations
Objective
The aim of this randomized controlled clinical trial is to examine single-tooth implant abutments and restorations in the esthetic zone Restorations will be fabricated using two different techniques Zirconia CADCAM ZCC implant abutments and restorations will be compared to conventional prefabricated Titanium TCF implant abutments and porcelain-fused-to-metal restorations using reproducible aesthetic objectivesubjective and biologic parameters
Hypothesis
The hypothesis of this investigation is that ZCC implant abutmentsrestorations test group will achieve better biologic and esthetic outcomes when compared with TCF types control group The null hypothesis is defined as follows ZCC implant abutmentsrestorations and TCF implant restorations are indistinguishable when biologic and esthetic outcomes are compared
Clinical Significance
CADCAM technology has been involved in the fabrication of dental abutments and restoration for the purpose of improving the biologic and esthetic results This assumption has been formulated primarily from subjective interpretations as objective assessments from randomized controlled trials are sparse at best This study will be significant for clinical dentistry in that it will create evidence on the clinical long-term performance of Zirconium CADCAM abutments and ceramic crowns compared to stock titanium abutments and porcelain-fused-to-metal restorations using subjective and objective evaluation parameters that will be statistically compared
Materials and Methods
Patients with an indication for an implant supported single tooth restoration in the esthetic zone will be included in the study according to the following criteria
Inclusion Criteria
General
1 Age 21 years
2 Absence of relevant medical conditions
3 Absence of periodontal diseases
4 The opposing dentition must be natural teeth or fixed not removable restorations on teeth or implants
5 Availability for 5-year follow-up
Local
1 One missing tooth in the esthetic zone An esthetic area is defined as any area that is visible in the patients full smile 3rd ITI consensus conference 2004
2 Presence of two intact adjacent teeth which are either non-restored or with minor restorations small composite restorations
3 Adequate native bone to achieve primary stability
4 Adequate band of keratinized mucosa at least 2mm
5 Full Mouth Plaque Scores FMPS and Full Mouth Bleeding Scores FMBS 25
Exclusion criteria
General
1 Heavy smokers more than 10 cigarettesday
2 Presence of conditions requiring chronic prophylactic use of antibiotics
3 Medical conditions requiring prolonged use of steroids
4 History of radiation therapy to the head or neck or history of chemotherapy
5 Physical handicaps that would interfere with the ability to perform adequate oral hygiene
6 Patients with inadequate oral hygiene
Local
1 Adjacent implant
2 Presence of periapical radiolucencies at the adjacent teeth
3 Missing adjacent teeth
4 Local inflammation including untreated periodontitis
5 Persistent intraoral infections
6 Untreated mucosal diseases
Subject population Patients will be recruited from the patient pool of the Teaching and Faculty Practice at the Harvard School of Dental Medicine A 12-month period will be allowed to enroll the patients in this study The mean treatment outcome will be compared between the two randomized patient groups allowing for detection of the smallest clinically important differences between these means TheSealedEnvelope- httpwwwthesealedenvelopecom powerphp
Patient entry informed consent patient registration randomization and blinding An informed consent approved by the Harvard Medical SchoolHarvard School of Dental Medicine Committee on Human Studies will be obtained for all subjects to be entered in this study Its conduct will adhere to the principles outlined by the Office for Research Subject Protection of the Harvard Medical School Harvard School of Dental Medicine Each subject will be randomly assigned to one of the two treatment options A random permuted block approach will be used to allocate patients into one of the treatment groups A sealed envelope containing the treatment group control or test group will be assigned to each patient Subsequently and according to the assigned treatment a ZCC restoration test group or a TCF ceramo-metal control group will be fabricated and delivered to the clinician
For subjective evaluation the trial design will be on a double blinding level which means that neither patients nor expert clinicians will know which treatment the patients are randomized to This can be achieved by concealing allocation information from patients and by using expert clinicians who are otherwise not involved in the patients care to assess treatment difficulties and outcomes without knowing their treatment group
Treatment groups
30 patients will be randomly allocated to control or test group presented in Table 1
Group n 30 patients Implant Abutment Crown Loading Test group n15 ZCC BL Straumann Etkon Zirconia Cement-retained Etkon Zirconia 6-8 weeks control group n15 TCF BL Straumann Crossfit titanium Cement-retained PFM 6-8 weeks
Evaluation Parameters and time schedule
Patients will be evaluated for esthetic objective and subjective parameters and biologic parameters as well as the success criteria through out the study period The baseline measurements are defined as the measurements taken during the healing period after insertion of bone level implant
During the healing period after insertion of a Straumann Bone Level implant following standard surgical procedures patients will use removable provisional prostheses
The implants will be examined for successful tissue integration according to the criteria of success Buser et al 1990 at every recall
Criteria of success
1 Absence of persistent subjective complaints such as pain foreign body sensation andor dysaesthesia
2 Absence of a recurrent peri-implant infection with suppuration
3 Absence of mobility
4 Absence of a continuous radiolucency around the implant
Esthetic parameters
Objective parameters
Standardized intra-oral digital photograph 11 magnification An intra-oral photograph will be taken positioning the plane of the camera body parallel to the vestibular face of the teeth adjacent to the single edentulous gap Figure 1
Papilla Height Distance between the mesial and distal papilla and the zenith of the mid-facial gingival margin of the adjacent teeth The distance from the most coronal part of the mesial and distal papillae to the zenith of adjacent teeth will be measured from study casts and digital photographs Figure 2
Buccal gingival margin measurement Distance between the mid-facial gingival margin and the incisal edge of adjacent teeth The distance from the zenith of adjacent teeth to the most coronal part of the incisal edge will be measured from study casts and digital photographs This measurement will serve to determine the buccal gingival recessiongrowth when compared with further measurements It will be recorded as 0 at baseline Figure 3
Study cast
Spectrophotometer recording at adjacent teeth A spectrophotometer Crystaleye Olympus Japan will be used to select and digitally record the shade for each adjacent tooth The sterilizable adapter of the spectrophotometers intra-oral camera will be positioned on the alveolar process over the respective adjacent tooth Once the resulting video image of the tooth is centered in an orthoradial way in the measuring square depicted on the computer screen the spectrophotometric data will be recorded three consecutive times for each tooth This data will be later compared with records obtained from final crowns by repeating the spectrophotometer measurement over the control and test group restorations Figure 4
Buccal periimplant mucosa margin Distance between mid-facial gingival margin and incisal edge of the implant restoration At implant crown insertion the distance from the zenith of the implant restoration to the most coronal part of the incisal edge will be measured from study casts and digital photographs This measurement will serve to determine the buccal gingival recessiongrowth when compared with further measurements It will be recorded as 0 at the implant crown insertion Figure 5
Subjective parameters
1 Visual Analogue Scale VAS of patients judgment on
At baseline detriment of hisher esthetic appearance and respective expectations
At crown insertion
Overall treatment satisfaction
Accomplishment of initial expectations
At 1 6 months 1 3 and 5 year follow up
Overall treatment satisfaction
Impact on self-esteem
Functionality
2 Visual Analogue Scale VAS of 3 expert clinicians judgments on the case difficulty
Parameters Follow-up time schedule Baseline At insertion 1 month 6 months 1 year 3 years 5 years
Esthetic
Objective
1 11 digital photograph
2 Papilla height
3 Buccal gingival margin
4 Study cast
5 Spectrophotometer
6 Buccal periimplant mucosa margin
Subjective
1 VAS questionnaire for patients
2 VASquestionnaire from experts
Biologic parameters
1 mPI Modified plaque index Mombelli et al 1987 for evaluation of oral hygiene standard 0 No detection of plaque 1 Plaque only recognized by running a probe across the smooth marginal surface of the implant 2 Plaque can be seen by the naked eye 3 Abundance of soft material
2 mBI Modified sulcus bleeding index mBI Mombelli et al 1987 0 No bleeding when a periodontal probe is passed a long the gingival margin adjacent to the implant 1 Isolated bleeding spots visible 2 Blood forms a confluent red line on margin 3 Heavy or profuse bleeding
3 simplified GI Simplified Gingival Index Apse et al 1991 0 Normal mucosa 1 Minimal inflammation with color change and minor edema 2 Moderate inflammation with redness edema and glazing 3 Severe inflammation wit redness edema ulceration and spontaneous bleeding without probing
4 Microbiological sample Microbial samples from a tooth in the same sextant as the implant and from the implant healing cap prior to its initial removal at the start of the restorative procedures will be obtained Additional samples will be taken at 1month 6 12 36 and 60 months after the insertion of the restoration The samples will be analysed for P gingivalis T forsythia B forsythus Tdenticola F nucleatum P micra P micros P nigrescens P intermedia C rectus C gracilis E nodatum and S constellatus Quirynen et al 2002 Keller et al 1998 Conrad et al 1996 Sample analysis will be performed at the Forsyth Institute Boston MA on a contractual basis Samples will be identified only by their number for this purpose No patient identifying data will be revealed The correlation between the periimplant microflora before and after loading within the same subject as well as potential differences in quantity and composition of the microflora of ZCC and TCF implant abutments and restorations will be analysed
5 Standardized periapical radiograph to assess DIB values Standardized peri-apical long cone parallel radiographs of the implant Harris et al 2002 will be taken For standardization of radiographs a film holder will be attached to a custom-made bite splint This same device will be used during the whole study for radiographic records From these radiographs bone resorption will be measured as distance from the implant shoulder to first bone-to-implant contact DIB Figure 6
6 Width of keratinized facial mucosa
Parameters Follow-up Time schedule Baseline Crown Insertion 1 mos 6 mos 1 year 3 years 5 years
Biologic
1 mPI modified Plaque Index
2 mBI modified sulcus Bleeding Index
3 simplified GI Gingival Index
4 microbiological sample
5 PA Periapical X-ray for DIB
6 Width of keratinized facial mucosa
D Mechanical Biologic and Technical complications An evaluation of the mechanical biologic and technical complications will be performed at every recall visit Mechanical complications would be defined as all those complications that involve the prosthesis such as abutment screw loosening fracture of the veneer material fracture of the crown framework abutment screw fractures and implant fractures The category of biologic complications will include the complications that involve the soft tissues ex fistulas suppuration bleeding gingival inflammation and soft tissue dehiscence Technical complications would be defined as those complications that are related to lab procedures and fabricating techniques ex abutment and crown emergence profile abutment and crown fit
Complications Follow-up Time Schedule Baseline At insertion 1 mo 6 mos 1 year 3 years 5 years
Mechanical
1 Abutment screw loosening
2 Fracture of a veneer material
3 Fracture of the crown framework
4 Fractures of abutment screws
5 Fractures implants
Biologic
1 Fistulas
2 Suppuration
3 Bleeding
4 Gingival inflammation
5 Soft tissue dehiscence
Technical
1 Abutment emergence profile
2 Crown emergence profile
3 Abutment fit
4 Crown fit
Statistical Analysis After data collection and completion of the investigation a one-way analysis of variance ANOVA will be used to compare the mean values of all objective and subjective parameters Their variance will be broken down into two components a between groups component control group vs test group at baseline crown insertion and each follow-up period and b within group component at baseline crown insertion and each follow-up period A multiple LSD range test confidence level 95 will be applied to determine which means differ statistically from each other
Timetable June 2009 beginning of the study May 2010 deadline for patients entry and allocation August 2010 deadline for data collection of baseline and crown insertion measurements September 2010 deadline for data collection of 1-month follow up measurements February 2011 deadline for data collection of 6-month follow up measurements August 2011 deadline for data collection of 12-month follow up measurements August 2012 deadline for data collection of 24-month follow up measurements August 2013 deadline for data collection of 36-month follow up measurements August 2014 deadline for data collection of 48th month follow up measurements August 2015 deadline for data collection of 60th month follow up measurements February 2016 deadline for final publication of data
References
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a cross-sectional retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores J Periodontol 2009 80 140-151
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Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None