Correlation between placement torque and survival of single-tooth implants.
OBJECTIVE
This study evaluated the survival parameters of single-tooth implants through clinical and radiographic analysis.


METHODS
Implants were restored within a 24-hour period with a provisional crown designed to receive an occlusal masticatory load. This approach was compared to implants restored after a healing period (the control group). Forty-six implants were placed in 23 patients who were each treated with 2 Frialit-2 implants placed in sites between the second premolar in the maxilla or mandible. The manufacturer's recommended formal surgical procedure was followed, and primary stability was standardized with a minimum insertion torque of 20 Ncm. The sites were randomly selected, and the clinical and radiographic parameters were standardized with individual templates.


RESULTS
Data were collected at 24 h, and at 1, 3, 6, 12, 18, and 24 months. The experimental group included 10 failed implants; 9 of the failed implants had been placed with an insertion torque of 20 Ncm. One implant from the control group failed during the 24-month follow-up period. The survival rate was independent of implant length, site position, and bone quality and quantity. Relative risk for implant failure was associated with insertion torque (relative risk 0.79 [CI: 0.66-0.930]; Cox regression) (P < or = .007), in the experimental group but was not significant for those in the control group (ie, implants placed after a healing period; relative risk 0.78 [CI: 0.34-1.78]; Cox regression) (P < or = .057). To achieve osseointegration, it was found that an insertion torque above 32 Ncm was necessary (chi2= 15.68; P < or = .004).


CONCLUSIONS
A careful evaluation is necessary for a better understanding of the survival rates of immediately loaded implants. In this study, insertion torque was associated with the potential for risk, which can be decreased by 20% per 9.8 Ncm added.


CONCLUSIONS
Given these results, and considering the number of patients treated, immediate provisional crowns should only be proposed with early loading if an appropriate initial insertion torque has been applied.
Ottoni
Judith Maria Pinheiro
JM
Brazilian Association of Odontology, Vitória, Espirito Santo, Brazil. ottoni@terra.com.br
Oliveira
Zilda Fagundes Lima
ZF
Mansini
Roberto
R
Cabral
Antonio Melo
AM
D000293:Adolescent; D000328:Adult; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology; D003442:Crowns; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis; D003831:Denture, Partial, Immediate; D005260:Female; D005889:Gingival Recession / Q000209:etiology; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011859:Radiography; D016019:Survival Analysis; D013997:Time Factors; D019415:Torque