GAP Australasian Dentist Sept Oct 2020

Category 50 Australasian Dentist clinical R eplacement of missing teeth with dental implants represents one of the most successful treatment in modern medicine. However, failures do occur and failure rates in the range from 5 to 8% for routine procedures 1, 2 and up to 20% in major grafting cases 3 during at least 5 years of function are known from literature reviews. Many implant losses may be explained as biomechanically induced failures 1, 4, hence there is a need to remove any doubt and to assure the osseointegration before final restoration. To achieve sufficient osseointegration to assure a stable dental implant, a variable amount of healing time is applied before the attachment of the dental prosthesis. The healing time depends on several factors, e.g. patient status, age and health, placement of implant etc. A stable implant can be defined as the absence of clinical mobility, supporting the definition of osseointegration 7 . When discussing development of implant stability and osseointegration, it is not enough to only make use of one single value. If an ISQ measurement is done only before final restoration, and the registration is a value of 65 ISQ – is that good or bad in terms of final restoration? It is impossible to say, if you do not know where you started. In general, values above ISQ 70 indicate a stable implant with low micromobility. These cases might be recommended for one- stage and immediate loading 7, 9, 10, 11, 12 . But in any case, a second measurement is recommended before the final restoration to verify osseointegration (see Fig 1). Initial values in the range of 75 ISQ means the implant is already so stable that osseointegration cannot add stability in a significant way. The proof of osseointegration is the lack of a drop in ISQ (see Fig 1). If the implant has a low initial ISQ, osseointegration will add stability over time. A decrease in ISQ could speak for additional actions, e.g. extended healing time. The primary stability of the implant consists of the biomechanical stability resulting from implant insertion. Secondary stability of the implant is the sum of mechanical stability, which decreases with time (after placement of implant), and biologic stability (osseointegration), which increases with time. Typically, with most implant systems an initial decrease in stability (Fig 2) is observed (due to bone relaxation), followed by a subsequent increase in stability as the formation of new bone stabilizes the implant 5, 6, 7, 8 . u References: Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology. Eur J Oral Sci. 1998;106:527-51. Berglundh T, Persson L, Klinge B. A systematic review of the incidence of biological and technical complications in implant dentistry reported in prospective longitudinal studies of at least 5 years. J Clin Periodontol. 2002;29 Suppl 3:197 -212; Sjöström M, Sennerby L, Nilson H, Lundgren S. Reconstruction of the atrophic edentulous maxilla with free iliac crest grafts and implants: a 3-year report of a prospective clinical study. Clin Implant Dent Relat Res 2007:9: 46–59. Sennerby L, Roos J. Surgical determinants of clinical success of osseointegrated oral implants. A review of the literature. Int J Prosthodont 1998: 11: 408–420. Bogaerde LV, Pedretti G, Sennerby L, Meredith N. Immediate/Early function of Neoss implants placed in maxillas and posterior mandibles: an 18-month prospective case series study. Clin Implant Dent Relat Res. 2010;12 (Suppl 1):e83 -94. Ostman PO, Hellman M, Sennerby L. Direct implant loading in the edentulous maxilla using a bone density-adapted surgical protocol and primary implant stability criteria for inclusion. Clin Implant Dent Relat Res. 2005;7 Suppl 1:S60-9. Sennerby et. Al. Periodontology 2000, Vol. 47, 2008, 51–66 Rosen PS. Measurement of the "Bungee Dip" in Implant Stability Using Resonance Frequency Analysis: Two Case Reports. Compend Contin Educ Dent. 2018 Nov/Dec;39(10):706-712. Kokovic V, Jung R, Feloutzis A, Todovoric V, Jurisic M, Hämmerle C. Clinical Oral Implants Research, 00, 2013, 1-6 M Bornstein, C Hart, S Halbritter, D Morton, D Buser, Prof. Dr. med. dent. Clin Implant Dent Relat Res 2009 S Hicklin, E Schneebeli, V Chappuis, S Francesco, M Janner, D Buser, U Brägger. Clin. Oral Impl. Res. 00, 2015; 1-9 L. Milillo, C. Fiandaca, F. Giannoulis, L. Ottria, A. Lucchese, F. Silvestre, M. Petruzzi. Oral & Implantology – anno IX – n. 3/2016 How to make use of multiple measurements to optimize treatment time Figure 2. Development of osseointegration based on a series of measurements during the implant treatment. Figure 1. Osseointegration development based on two measurements, one during initial insertion and one before final restoration.