A 10-year prospective study of ITI dental implants placed in the posterior region. II: Influence of the crown-to-implant ratio and different prosthetic treatment modalities on crestal bone loss.
OBJECTIVE
To evaluate the influence of the crown-to-implant ratio (C/I) ratio and different implant prosthetic treatment modalities on crestal bone loss around dental implants placed in the posterior region.


METHODS
A total of 192 ITI dental implants were consecutively placed in premolars and molars of 83 partially edentulous patients. All implants were restored by means of ceramic-to-metal fused fixed partial dentures or a single crown. Patients were followed as part of a prospective longitudinal study focusing on implant success. Surgical, radiographic and clinical variables were collected at the 1-year recall after implant placement and at the most recent clinical evaluation. Radiographic parameters were evaluated on periapical radiographs taken with a standardized long-cone paralleling technique. Implant restorations were divided into three groups according to their respective clinical C/I ratios: (a) 0-0.99, (b) 1-1.99 and (c) >or=2.


RESULTS
The mean clinical C/I ratio was 1.77+/-0.56 mm. A total of 51 implants (26.5%) showed a clinical C/I ratio equal to or greater than 2. In this group, three implants failed, giving a cumulative survival rate of 94.1%. Crestal bone loss was -0.34+/-0.27 mm in group a, -0.03+/-0.15 mm in group b and -0.02+/-0.26 mm in group c. Differences among groups were statistically significant (P=0.009). Mode of retention, splinting or presence of cantilever extensions did not have an effect on crestal bone loss around ITI dental implants.


CONCLUSIONS
Implant restorations with C/I ratios between 2 and 3 may be successfully used in the posterior areas of the jaw.
Blanes
Rafael Juan
RJ
Department of Fixed Prosthodontics and Occlusion, Geneva Dental School, Geneva, Switzerland.
Bernard
Jean Pierre
JP
Blanes
Zulema Maria
ZM
Belser
Urs Christoph
UC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology; D000704:Analysis of Variance; D001641:Bicuspid; D003442:Crowns; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects* / Q000706:statistics & numerical data; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000000981:diagnostic imaging / Q000534:rehabilitation / Q000601:surgery; D008297:Male; D008875:Middle Aged; D008963:Molar; D010512:Periodontal Index; D011446:Prospective Studies; D011859:Radiography; D012737:Sex Factors; D016896:Treatment Outcome; D016474:Weight-Bearing