Influence of lateral pressure to the implant bed on osseointegration- An experimental study in dogs

Faculty of Dentistry of Araçatuba, UNESP - São Paulo State University, São Paulo, Brazil.
Clinical Oral Implants Research (Impact Factor: 3.89). 11/2010; 21(11):1264-70. DOI: 10.1111/j.1600-0501.2010.01941.x
Source: PubMed


To study osseointegration and bone-level changes at implants installed using either a standard or a reduced diameter bur for implant bed preparation.
In six Labrador dogs, the first and second premolars were extracted bilaterally. Subsequently, mesial roots of the first molars were endodontically treated and distal roots, including the corresponding part of the crown, were extracted. After 3 months of healing, flaps were elevated and recipient sites were prepared in all experimental sites. The control site was prepared using a standard procedure, while the test site was prepared using a drill with a 0.2 mm reduced diameter than the standard one used in the contra-lateral side. After 4 months of healing, the animals were euthanized and biopsies were obtained for histological processing and evaluation.
With the exception of one implant that was lost, all implants were integrated in mineralized bone. The alveolar crest underwent resorption at control as well as at test sites (buccal aspect ∼1 mm). The most coronal contact of bone-to-implant was located between 1.2 and 1.6 mm at the test and between 1.3 and 1.7 mm at the control sites. Bone-to-implant contact percentage was between 49% and 67%. No statistically significant differences were found for any of the outcome variables.
After 4 months of healing, lateral pressure to the implant bed as reflected by higher insertion torques (36 vs. 15 Ncm in the premolar and 19 vs. 7 Ncm in the molar regions) did not affect the bone-to-implant contact.

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    • "The differences were statistically significant only for the loaded implants. For the unloaded sites, the results from the present experiment corroborate those from another experiment (Pantani et al. 2010) in which no statistically significant differences were disclosed when implants were installed with insertion torques within a range of 7–36 Ncm. However, these results are in disagreement with those from an experiment in sheep (Trisi et al. 2011). "
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    ABSTRACT: To evaluate the influence of different insertion torques on healing of implants loaded immediately or left unloaded. In six Labrador dogs, all mandibular premolars and molars were extracted. After 4 months of healing, flaps were elevated, and two implant sites were prepared at each side of the mandible. The distal sites were prepared conventionally while the mesial sites were underprepared by 0.3 mm. As a consequence, different final insertion torques of about 30 Ncm at the distal and >70 Ncm at the mesial sites were recorded. Healing abutments were applied to the left and transmucosal abutments to the right side. Flaps were sutured, crown preparation of the upper right second and third premolars was performed, and impressions were taken. Within 24 h, crowns were cemented both to implants and teeth in the right side of the mouth. After 4 months, the animals were sacrificed and ground sections obtained for histological evaluation. A higher buccal bony crestal resorption and a more apical position of the coronal level of osseointegration were found at the loaded compared with the unloaded sites. MBIC% and percentages of peri-implant mineralized tissue (MB%) were higher at the loaded compared with the unloaded sites. Moreover, a higher MBIC% was found at the lower compared with the higher final insertion torque. Immediate loading does not seem to have a negative effect on osseointegration. High torque values for the immediate loading procedures were not necessary. Probably, low torque values, were sufficient to obtain primary stability and hence may provide better osseointegration than high torque value.
    Clinical Oral Implants Research 12/2013; 26(1). DOI:10.1111/clr.12305 · 3.89 Impact Factor
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    Clinical Oral Implants Research 08/2011; 23(8):954-7. DOI:10.1111/j.1600-0501.2011.02246.x · 3.89 Impact Factor
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    ABSTRACT: To conduct a randomised controlled trial to evaluate the short-term clinical and radiographic efficacy of the NobelActive™ system and to evaluate the relative importance of achieving primary stability at placement. A total of 32 subjects were recruited and, using a split-mouth design, the NobelActiveTM implant was compared with a contralaterally matched Brånemark implant. Both implants were placed in a single surgical procedure into healed sites using a one-stage protocol and reviewed at monthly intervals. NobelActiveTM implants were functionally loaded with provisional restorations at 1 month and all implants were restored with final crowns 3 months post-implant placement. The implant was assessed using peak insertion torque values, resonance frequency analysis (RFA), clinical parameters, digital subtraction radiography, and cone beam computed tomography. The insertion torque was significantly greater for the NobelActiveTM implant group (P = 0.02), although no observable difference in RFA values were found. Preliminary results of 6 months follow-up suggest comparable clinical and radiographic healing responses between the test and control implants. Within the limits of the sample population, the survival rates were lower with the test implants, although this difference was not statistically significant. The NobelActiveTM implant system requires higher insertion torques and can also achieve greater primary stability compared with a control implant system. Short-term survival and marginal bone levels of NobelActiveTM and control implants are comparable, although the NobelActiveTM implant system appeared to be more technique-sensitive.
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