Oral rehabilitation using Camlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface. Results from a prospective study with special consideration of short implants

OBJECTIVES: The purpose of the present clinical study was to report on the clinical performance of screw-cylinder implants with special consideration of the survival rate of short implants. MATERIAL AND METHODS: In this prospective study with consecutive patient recruitment, Camlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface and a triple-cam tube-in-tube implant-abutment connection have been used only. Two groups of implants were evaluated: implants of 9 and 11 mm in length were considered short, those of 13 and 16 mm were considered long. Besides clinical and radiographic parameters, data of complications, patients' subjective evaluation of treatment outcome, general medical history and smoking habits were recorded. RESULTS: Three hundred and thirty-three Camlog screw-cylinder implants were inserted in 133 patients. One hundred and twenty-nine patients were available for follow-up, representing 325 implants. The median observation period was 33 months (Q(25%) 26; Q(75%) 38). After a maximum observation period of 55 months, the Kaplan-Meier-survival analysis revealed no significant difference between the mean survival probabilities of 98.3% (n=59, patient-related) of short implants, and of 95.7% of long implants (n=70, patient-related) (P=0.162). No significant difference was found between implant survival rates considering maxilla (98.7%) and mandible (98.2%). A stratified analysis of short implants revealed a significant influence of premature cover screw exposures (P=0.02) and smoking (P=0.008) on implant survival. These influences were not found significant for long implants. CONCLUSIONS: The prognosis of short Camlog implants is comparable with that of long implants. Therefore, their clinical use instead of performance of sophisticated vertical augmentation procedures before installation of long implants might be considered as alternative treatment option. In smokers, the use of short implants should be considered cautiously, however. The risk of premature cover screw exposure should be minimized.