Resonance frequency analysis in relation to jawbone characteristics and during early healing of implant installation M. A. Huwiler B. E. Pjetursson D. D. Bosshardt G. E. Salvi N. P. Lang Authors’ afﬁliations: M. A. Huwiler, B. E. Pjetursson, D. D. Bosshardt, G. E. Salvi, N. P. Lang, School of Dental Medicine, University of Berne, Berne, Switzerland Correspondence to: Prof. Dr N. P. Lang School of Dental Medicine, University of Berne, Freiburgstrasse 7 CH-3010 Berne, Switzerland Tel.: þ 41 31 632 2577 Fax: þ 41 31 632 4915 e-mail: nplang@dial.eunet.ch Key words: implant stability, jawbone, micro-CT, osstell s , RFA, titanium implants, wound healing Objectives: To monitor resonance frequency analysis (RFA) in relation to the jawbone characteristics and during the early phases of healing and incorporation of Straumann s dental implants with an SLA surface. Material and methods: 17 Straumann 4.1 mm implants (10 mm) and 7 Straumann 4.8 mm implants (10 mm) were installed and ISQ determined at baseline and after 1, 2, 3, 4, 5, 6, 8 and 12 weeks. Central bone cores were analyzed from the 4.1 mm implants using micro CT for bone volume density (BVD) and bone trabecular connectivity (BTC). Results: Pocket probing depths ranged from 2–4 mm and bleeding on probing from 5–20%. At baseline, BVD varied between 24% and 65% and BTC between 4.9 and 25.4 for the 4.1 mm implants. Baseline ISQ varied between 55 and 74 with a mean of 61.4. No signiﬁcant correlations were found between BVD or BTC and ISQ Values. For the 4.8 mm diameter implants baseline ISQ values ranged from 57–70 with a mean of 63.3. Over the healing period ISQ values increased at 1 week and decreased after 2–3 weeks. After 4 weeks ISQ values, again increased slightly, no signiﬁcant differences were noted over time. One implant (4.1 mm) lost stability at 3 weeks. Its ISQ value had dropped from 68 to 45. However the latter value was determined after the clinical diagnosis of instability. Conclusion: ISQ values of 57–70 represented homeostasis and implant stability. However no predictive value for loosing implant stability can be attributed to RFA since the decrease occurred after the fact. Oral implants have been used in rehabilita- tion of the partially and completely eden- tulous patient for more than 30 years. Originally, clinical protocols were recom- mended to observe a healing period of 3–6 months before loading implants prostheti- cally and exposing then to full oral function (Bra ˚nemark 1972). Using oral implants with roughened surfaces, other implant systems generally recommended shorter healing periods not exceeding 3 months before prosthetic loading (Schroeder et al. 1976). With the development of more ‘os- teogenic’ roughened surfaces during the 1990s (Buser et al. 1991; Quinlan et al. 2005), advocated healing times before func- tional loading were further reduced to 6–8 weeks. Most recently, such surfaces with biologically active hydrophilic characteris- tics propagated even shorter healing periods (3–4 weeks; Buser et al. 2004). A prerequisite for functional loading is the achievement of stability of an oral implant. While stability may be guaranteed initially by macro-retention, such as threads or friction (primary stability at the Date: Accepted 22 May 2006 To cite this article: Huwiler MA, Pjetursson BE, Bosshardt DD, Salvi GE, Lang NP. Resonance frequency analysis in relation to jawbone characteristics and during early healing of implant installation. Clin. Oral Impl. Res. 18, 2007; 275–280 doi: 10.1111/j.1600-0501.2007.01336.x c  2007 The Authors. Journal compilation c  2007 Blackwell Munksgaard 275