Influence of underpreparation on primary stability of implants inserted in poor quality bone sites: an in vitro study.

PURPOSE The purpose of this present study was to investigate the relation between implant site underpreparation and primary stability in the presence of poor-quality bone. MATERIALS AND METHODS A study was performed on fresh humid bovine bone; samples presented no cortical layer with a cancellous structure inside and were obtained from the hip. The bones were firmly attached to a base device. Sixty sites were prepared according to the protocol provided by the manufacturer: a 2-mm pilot drill was introduced to the proper depth and then twist drills of 3 and 3.4 mm were used. After site preparation, 20 3.4- × 11-mm (standard protocol group), 20 3.8- × 11-mm (10% undersized group), and 20 4.5- × 11-mm (25% undersized group) implants were inserted at a calibrated maximum torque of 70 N-cm at the predetermined speed of 30 rpm. After implant insertion, variable torque work (VTW), maximum insertion torque (peak IT), and resonance frequency analysis (RFA) values were recorded. RESULTS The standard protocol group showed a mean VTW of 565.77 ± 219.12 N-cm, a peak IT of 11.3 ± 4.44 N-cm, and an RFA of 69.35 ± 7.35 implant stability quotient (ISQ). The 10% undersized group showed a mean VTW of 1,240.24 ± 407.78 N-cm, a peak IT of 20.26 ± 7.03 N-cm, and an RFA of 73.40 ± 2.33 ISQ. The 25% undersized group showed a mean VTW of 1,254.96 ± 727.49 N-cm, a peak IT of 17.15 ± 10.39 N-cm, and an RFA of 72.30 ± 6.70 ISQ. For VTW, the difference between the standard and undersized protocol values was statistically significant; for peak IT, the difference between the standard and 10% undersized protocol values was statistically significant; no other statistical differences were found between mean values. CONCLUSIONS In the presence of poor-bone quality, a 10% undersized protocol is sufficient to improve the primary stability of the implant; additional decreases do not seem to enhance primary stability values.

[1]  P. Coelho,et al.  Effect of drilling dimension on implant placement torque and early osseointegration stages: an experimental study in dogs. , 2012, Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons.

[2]  U. Lekholm,et al.  Patient selection and preparation , 1985 .

[3]  J. Jansen,et al.  The effects of implant surface roughness and surgical technique on implant fixation in an in vitro model. , 2006, Clinical oral implants research.

[4]  D. Mellström,et al.  Brånemark implants and osteoporosis: a clinical exploratory study. , 2001, Clinical implant dentistry and related research.

[5]  Summers Rb,et al.  A new concept in maxillary implant surgery: the osteotome technique. , 1994 .

[6]  A. Ekestubbe,et al.  Clinical outcome of Brånemark System implants of various diameters: a retrospective study. , 2002, The International journal of oral & maxillofacial implants.

[7]  J. Jansen,et al.  Biological limits of the undersized surgical technique: a study in goats. , 2011, Clinical oral implants research.

[8]  J. Jansen,et al.  Influence of the surgical technique and surface roughness on the primary stability of an implant in artificial bone with a density equivalent to maxillary bone: a laboratory study. , 2009, Clinical oral implants research.

[9]  A. Piattelli,et al.  Development of a new implant primary stability parameter: insertion torque revisited. , 2011, Clinical implant dentistry and related research.

[10]  Lars Sennerby,et al.  Implant stability measurements using resonance frequency analysis: biological and biomechanical aspects and clinical implications. , 2008, Periodontology 2000.

[11]  Pär-Olov Ostman Immediate/early loading of dental implants. Clinical documentation and presentation of a treatment concept. , 2008, Periodontology 2000.

[12]  P Schärer,et al.  Immediate occlusal loading of Brånemark implants applied in various jawbone regions: a prospective, 1-year clinical study. , 2001, Clinical implant dentistry and related research.

[13]  P Missika,et al.  Optimal implant stabilization in low density bone. , 2001, Clinical oral implants research.

[14]  J. Jansen,et al.  Study of the osseointegration of dental implants placed with an adapted surgical technique. , 2011, Clinical oral implants research.

[15]  R. Leesungbok,et al.  Differences in implant stability associated with various methods of preparation of the implant bed: an in vitro study. , 2012, The Journal of prosthetic dentistry.