The aim of this study was to investigate experimentally the mechanical and histological effect of drilling process on the stability of micro-implant used for the orthodontic anchorage. For this purpose, 32 micro-implants(Osas®, Epoch medical, 01.6 mm) were inserted into maxilla, mandible and palate in two beagle dogs. 16 micro-implants(8 per dog) were inserted after drilling with pilot drilling bur (drill method group). 16 micro-implants(8 per dog) were inserted without drilling (drill-free method group). After 1 week, micro-implants were loaded by means of Ni-Ti coil spring (Ni-Ti springs-extension´, Armco) with 200-300 gm force. Following 12 weeks, the micro-implants and the surrounding bone were removed. Before sacrifice, the mobilities were tested with Periotest®(Siemens). Undecalcified serial sections with the long axis were made and the histologic evaluations were done.
The results of this study were as follow ;
1. The osseointegration was found in both of drill-free method group and drill method group !.
2. Two of drill method group and one of drill-free method. group in 32 micro-implants, were lost after loading. 3: Thp mobilities of drill-free-method group were less than drill method group
4. The bone contact on surface of micro-implants in drill-free method group was more than drill method group but there
was no significant difference between groups.
5. The bone density in threads of micro-implants in drill-free method group was more than drill method group and there was significant difference between groups.
These results suggest that drill-free method in insertion of micro-implants is superior to drill method on the stabilities, bone remodeling and osseointegrations under early loading.
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