CATEGORY AUSTRALASIAN DENTIST 73 be used to determine the suitability of a dental implant for immediate loading or provisionalisation8. ISQ gives a quantitative value of the stability of the implant bone interface. When assessing the suitability of an implant for loading a number of clinical factors in addition to ISQ measurements should be taken into consideration; bone quality and quantity, implant location and numbers, change in ISQ since placement, prosthesis design and loading conditions and parafunctional habits. It has been widely demonstrated that Osstell can measure clinical implant stability and the changes that occur with time attributable to osseointegration13. Research studies with animal models and clinical patient measurements report an increase in ISQ values for typically 18 months following placement14 (Figure 5). is lower more new bone is laid down and the rise is ISQ is consequently greater. For example, primary ISQ values are lower in the maxilla than the mandible where the bone to implant contact is usually lower. After 18 months or so ISQ values reach an equilibrium15. The stability of an implant in an osteotomy is not uniform in all directions16 (Figure 6). This becomes obvious with implants placed in immediate extraction sites. Osstell can measure these differences and resolves them as two values; the high and low principal ISQ values. Often or marginal bone height surrounding an implant. A change in ISQ typically occurs before any clinical signs or symptoms are apparent and should be investigated. A decrease following placement may be due to overloading, infection or a loss of stability and remedial action may be taken with follow up ISQ measurements8. Dental implants do not osseointegrate at the same rate and much research has been undertaken to develop methods to accelerate osseointegration17. Implant surface modification is a possible method and it has been demonstrated that superhydrophilic surfaces can successfully reduce the healing time prior to implant loading18. It has been proposed by many workers that there is a decrease in stability shortly after implant placement. This may be due to a transient inflammatory reaction with short term bone resorption. It has been clearly demonstrated19 that a superhydrophilic surface (ProActive; Neoss ltd, UK) can eliminate this ‘dip’ in stability and results in an increase in ISQ measurements immediately after placement. Today, the clinical measurement of implant stability should be considered to be a routine part of clinicians armamentarium; it offers evidence based clinical practice, a method to assess the efficacy of treatment protocols, a communication tool for patients and an independent way of determining a clinicians experience. Osstell and ISQ measurements provide an excellent way for the clinician to understand how clinical techniques including bone augmentation and sinus lifts are contributing to implant stability and overall success. u For a complete list of references email gapmagazines@gmail.com Professor Neil Meredith info@pgids.net Figure 5. After Ostman 2000, Changes in ISQ following implant placement in differing bone qualities Figure 6. Variation in ISQ with orientation for implant in first molar region the two values are the same indicating symmetrical stability but they can be different in extraction sites or near the sinus for example. It is important to record both values independently as they are measuring different parameters. Averaging them or recording one value is inaccurate. It is therefore possible to measure osseointegration clinically and evaluate changes at the implant/bone interface. If a healing abutment has been attached to an implant ISQ measurement can be made at any time following implant placement and will give a good indication of the progressive bone formation at the interface. ISQ values may also decrease following implant placement due to a decrease in stiffness LINICAL 1800 806 450 www.amalgadent.com.au The Perfect Pair SEE INSIDE FRONT COVER FOR OFFER! Footer Ads #98.indd 2 28/04/2023 5:56:11 PM It is interesting to note that the increase in ISQ values is greater following implant placement when the primary stability and bone quality is lower. ISQ values of primary stability are higher in the mandible where the cortical: trabecular bone ratio is higher. This is because higher level of primary bone to implant contact (and ISQ) results in more interfacial remodelling. In the maxilla, where the bone to implant contact
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