Article

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

ABSTRACT

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 influence of the final insertion torque on osseointegration was evaluated in experimental animal studies (Pantani et al. 2010; Rea et al. 2014). In an experiment (Pantani et al. 2010), implants were installed in the mandible of dogs with a final torque insertion that ranged between 7 and 36 Ncm. No statistically significant differences were found among the various groups. "
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    ABSTRACT: To evaluate prospectively clinical and radiographic outcomes of 6- or 10 mm-long implants with moderately rough surface (SLA(®) ) loaded within 7 weeks from installation and supporting single crowns in the posterior regions in the course of 5 years of loading. Sixty implants with a moderately rough surface, 30 tests (6 mm long, 4.1 mm in diameter) and 30 controls (10 mm long, 4.1 mm in diameter), were placed in posterior regions in 45 patients. After 6 weeks, impressions were taken and the implants were restored with a single fixed prosthesis made with gold-palladium alloy and porcelain. Survival rate and marginal bone loss were evaluated yearly. The clinical crown/implant ratio was calculated. During the follow-up period, five implants, four tests and one control, were lost. Of the four test implants, one was lost before loading, two between the 2nd and the 3rd years, and one during the 4th year of the follow-up period. The control implant was lost during the first year of function. Consequently, after 5 years of follow-up, a survival rate of 86.7% and 96.7% was observed at the test and control sites, respectively. The results of this study showed that 6-mm-long implants supporting single crowns loaded within 7 weeks from installation lose a small amount of marginal bone during 5 years of functional loading, similar to that of 10-mm-long implants. However, a higher degree of implant loss was recorded at the short implants, probably due to the fracturing of the surrounding bone. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
    No preview · Article · Feb 2015 · Clinical Oral Implants Research
    • "(a–b) close to 0 sites; (c) ~30 Ncm site. to the buccal and lingual cortical plates (Pantani et al. 2010). "
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    ABSTRACT: Objective To study bone healing at implants installed with different insertion torques.Material and methodsIn six Labrador dogs, all mandibular premolars and first molars were extracted. After 4 months of healing, flaps were elevated, and two implant sites were prepared at each side of the mandible. In the right side of the mandible, the distal sites were prepared conventionally, while the mesial sites were over-prepared by 0.2 mm. As a consequence, a final insertion torque of ~30 Ncm at the distal and a minimal insertion torque close to 0 Ncm at the mesial sites were obtained. In the left sides of the mandible, however, the recipient sites were underprepared by 0.3 mm resulting in an insertion torque of ≥70 Ncm at both implants. Cover screws were applied, and flaps sutured to fully submerge the experimental sites. After 4 months, the animals were sacrificed and ground sections obtained for histological evaluation.ResultsThe mineralized bone-to-implant contact was in the range of 55.2–62.1%, displaying the highest value at implants with ~30 Ncm insertion torque and the lowest value at the implant sites with close to 0 Ncm insertion torque. No statistically significant differences were revealed. Bone density was in the range of 43.4–54.9%, yielding the highest value at implants with ≥70 Ncm insertion torque and the lowest at the implant sites with close to 0 Ncm insertion torque. The difference between the sites of ~30 Ncm and the corresponding ≥70 Ncm insertion torque reached statistical significance.Conclusions Similar amounts of osseointegration were obtained irrespective of the insertion torque applied. Moreover, implants installed in sites with close to 0 Ncm insertion torque may properly osseointegrate as well.
    No preview · Article · Mar 2014 · Clinical Oral Implants Research
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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.
    Full-text · Article · Dec 2013 · Clinical Oral Implants Research
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