Insertion Techniques and Primary Stability of TADs: An In Vitro-Study.
I. Lantsberg1, R. Delgado-Ruiz2, G.E. Romanos1
1Dept. of Periodontology, Laboratory for Periodontal-, Implant-, Phototherapy (LA-PIP), 2Dept. of Prosthodontics and Digital Technology School of Dental Medicine, Stony Brook University, Stony Brook, NY
Introduction: The anchorage obtained with Temporary Anchorage Devices (TADs) has become an effective aid for orthodontists in resolving challenging malocclusions. Clinical success depends among other factors, on the mechanical stability after TADs placement. The aim of this study was to examine the effect of different insertion techniques and TADs length on primary stability in bone Type I in vitro.
Methods: A total of 80 (four groups, 20 each), grade 5 titanium Tomas-mini-implants were inserted into polyurethane resin-blocks simulating Type I-bone. The diameters of all mini-screws were 1.6mm with two different lengths: 8mm (Groups A1, B1) and 10mm (Groups A2, B2). Implants placed according to the manufacturer’s guidelines. The implants were inserted perpendicular to the block using either the manufacturer’s supplied ratchet or using a manual screwdriver. Vertical compressive forces were applied during insertion with the manual screwdriver, while only torque was functional with the ratchet. Four experimental-groups were compared:
Group A1 – 8mm inserted with ratchet
Group A2 – 10mm inserted with ratchet
Group B1 – 8mm inserted with manual screwdriver
Group B2 – 10mm inserted with manual screwdriver
Implant stability values (PTV) was measured with the Periotest device; two measurements at different angles were taken (total 160 values). Statistical analysis was performed using One-way ANOVA-test with Bonferroni’s post-test. Significance was set as p<0.05.
Results: The PTV values were similar between groups (Figure1), statistical comparison revealed no significant differences between groups (Table1).
|Conclusions: No significant difference in primary stability was detected when comparing the two insertion methods for 8mm and 10mm TADs. The results suggest that applying compression with the implant-screwdriver does not guarantee a greater stability when inserting 1.6mm-wide mini-implants. It can be concluded that the practitioner can safely utilize both insertion techniques to achieve similar primary stability for clinical use. Shorter implants might be recommended in case of limited bone thickness.|