ABSTRACT
OBJECTIVES: To evaluate the magnitude of error in transferring the planned position of implants from reformatted CT scans to a surgical template. METHODS: The deviation between the position of the apex of the proposed implant in paraxial CT reformats and on the corresponding study cast was measured in 77 prospective sites in five maxillas and nine mandibles. RESULTS: The transfer error was 0.6 (s.d. 0.4) mm in the maxilla and 0.3 (s.d. 0.4) mm in the mandible. CONCLUSIONS: The transfer errors detected in this investigation are not clinically relevant. Other factors involved in transferring positional and angular measurements from reformatted CT to the surgical site may result in more significant errors.
Subject(s)
Dental Implantation, Endosseous , Image Processing, Computer-Assisted , Patient Care Planning , Tomography, X-Ray Computed , Dental Implantation, Endosseous/instrumentation , Dental Implantation, Endosseous/methods , Dental Implants , Denture Bases , Humans , Jaw, Edentulous/diagnostic imaging , Jaw, Edentulous/surgery , Jaw, Edentulous, Partially/diagnostic imaging , Jaw, Edentulous, Partially/surgery , Mandible/diagnostic imaging , Mandible/surgery , Maxilla/diagnostic imaging , Maxilla/surgery , Models, Dental , Prospective Studies , Radiographic Image Enhancement , Statistics as Topic , TitaniumABSTRACT
Previous in vitro studies have shown that a mean gap of less than 4 microns between prefabricated crowns and implants of the Ha-Ti implant system is not a barrier to infiltration by Staphylococcus aureus. These studies confirmed earlier in vivo work showing that a multitude of oral microorganisms could colonize and infiltrate these gaps. In the present investigation, 30 Ha-Ti implant-crown assemblies were tested for bacterial leakage after the gaps were sealed with the chlorhexidine-containing varnish Cervitec. S. aureus leakage into the totally submerged test specimens was detected in 1 of 5 samples incubated for 4 weeks, while no leakage was detected in specimens incubated for 3, 5, 6, 7, and 8 weeks. When the sealed test specimens were partially submerged (that is, excluding the screw hole of the crown) and incubated for 3 to 11 weeks, none of the internal surfaces of the 30 test specimens manifested contamination. The clinical relevance of gap sealing in maintaining inflammation-free marginal mucosa and in achieving clinically successful treatment of peri-implantitis has yet to be determined.
Subject(s)
Crowns/microbiology , Dental Implants/microbiology , Dental Prosthesis, Implant-Supported/microbiology , Staphylococcus aureus/growth & development , Anti-Infective Agents, Local/administration & dosage , Anti-Infective Agents, Local/therapeutic use , Biocompatible Materials/chemistry , Chlorhexidine/administration & dosage , Chlorhexidine/therapeutic use , Drug Combinations , Equipment Contamination/prevention & control , Humans , Hydroxyapatites/chemistry , Mouth/microbiology , Paint , Periodontitis/microbiology , Periodontitis/prevention & control , Staphylococcus aureus/drug effects , Stomatitis/microbiology , Stomatitis/prevention & control , Surface Properties , Thymol/administration & dosage , Thymol/therapeutic use , Titanium/chemistryABSTRACT
A mean gap of less than 4 microm following laboratory procedures and continuous loading was demonstrated in prefabricated crowns of the Ha-Ti implant system in earlier studies. The clinical relevance of such high precision in maintaining inflammation free marginal mucosa is yet to be determined. In this present investigation, the complete assembly of Ha-Ti implants including prefabricated screw-retained crowns was tested for bacterial leakage under controlled conditions in vitro. The gaps were shown not to be a barrier for Staphylococcus aureus which were used as test bacteria. Bacterial leakage through these gaps from the environment to the interior of the assembly and vice versa was observed within 24-120 h. The main path of bacterial penetration was possibly found to be through the transversal screw hole and not through the marginal gap of the prefabricated crowns.
