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Title Long-term Clinical Outcomes of Anterior Screw-Retained and Cement-Retained Implant Restorations are Equivalent
Clinical Question Is there a difference in long-term success of anterior screw-retained vs. cement-retained implant restorations in healthy patients?
Clinical Bottom Line The evidence suggests that both methods of restoring anterior implants are equally clinically acceptable in satisfying the patient and in maintaining health of peri-implant soft tissues.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 20809428Sherif/2011102 patients, 49% female; mean age 47.3 ± 14.9 years; ≥1 maxillary anterior implants/patient; 214 implants included; 53.4% screw-retained restorations, 46.6% cement-retained restorationsMulti-center prospective cohort study
Key resultsStatistically significant differences were found in peri-implant tissue health (p ≤ 0.05) after 60 months following restoration delivery. Soft tissues around cement-retained restorations showed higher modified plaque scores and sulcular bleeding indices than those of screw-retained restorations. Despite the differences, these parameters of the tissue health were considered low. There were no statistically significant differences in measurements of keratinized mucosae and gingival levels (p ≥ 0.05) between the study groups after 60 months. As with clinician-assessed outcomes, there were no statistically significant differences between groups (p ≥ 0.05) in patient-assessed fit, function, and esthetics after 60 months.
#2) 16907767Weber/200680 patients, 152 maxillary anterior implants; 93 (61.9%) screw-retained, 59 (38.1%) cement-retainedMulti-center prospective cohort study
Key resultsStatistically significantly higher mean plaque scores (p < 0.05) were shown on cement-retained restorations at 12- and 36-month follow-up assessments. Similar results for cement-retained restorations were found regarding sulcular bleeding indices (p < 0.05). Despite the differences, these parameters were considered low; and the keratinized mucosae and gingival levels of both study groups remained unchanged. The study suggests that patient-assessed outcomes were equally satisfactory between groups. However, clinician-assessed outcomes regarding esthetic fulfillment favored that of the cement-retained restorations (p < 0.05).
Evidence Search screw retained implant, cement retained implant, anterior
Comments on
The Evidence
Both articles reported similar study designs, study variables, clinical evaluation parameters, 90.2% - 100% completion rates; and came to similar conclusions. Weber et al., reported that mean plaque scores were significantly lowered (P < .05) on restorations receiving prophylaxis. However, Sherif et al., did not report anything regarding prophylaxis. In both studies, how the subjects were assigned to the screw-retained group vs the cement-retained group was up to the clinicians' discretions. This lack of random assignment to study groups may have lead to allocation bias. Therefore, both studies have questionable internal validity. Weber et al., did not describe the demographics of the patient sample, so the external validity of their study is questionable as well.
Applicability The evidence suggests that healthy adult patients receiving maxillary anterior implants can receive either screw-retained or cement-retained restorations with equal long-term satisfaction and adequate tissue health. Clinicians, however, may prefer the esthetics of cement-retained restorations.
Specialty/Discipline (General Dentistry) (Periodontics) (Prosthodontics) (Restorative Dentistry)
Keywords screw-retained, cement-retained, peri-implant soft tissue
ID# 2318
Date of submission: 08/08/2012spacer
E-mail blackd@livemail.uthscsa.edu
Author Damian Black
Co-author(s) e-mail
Faculty mentor/Co-author James M. Piper, II, DDS
Faculty mentor/Co-author e-mail james.piper@us.af.mil
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
post a rationale
by Damian Black (San Antonio, TX) on 09/14/2012
Apart from the esthetics of anterior implant-retained restorations, clinicians must understand the basic biology of peri-implant soft tissues to maximize longevity of these restorations (PMID: 18498584 ). A dog study by Berglundh, et al. demonstrated the relationship between peri-implant soft tissues and titanium implant/abutment surfaces as consisting of junctional epithelium and connective tissue, as in the periodontium of natural teeth. Even though these tissues differed in fiber content and organization compared to natural teeth, the investigators suggested that they provide an adequate seal around implants/abutments so long as adequate plaque control is performed. Teeth and implant-restorations share similar pathogeneses in plaque-induced soft tissue inflammation. This illustrates the importance of maintaining adequate oral hygiene and providing appropriate local debridement (e.g. prophylaxis) around implant-retained restorations. Another dog study by Berglundh and Lindhe demonstrated a constant of gingival dimension – analogous to biologic width – that has implications in soft tissue placement during implant surgeries. Appropriate soft tissue placement will influence its stability after the restoration is placed. Besides, the type of prosthetic abutment and the type of prosthesis may also play a role in the long term outcome of implant supported restorations as it will directly interface with the peri-implant soft tissues.
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