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Notes: Objective: The aim of the present study was to analyze some characteristics of advanced and progressive periimplantitis lesions in man.Material and methods: Soft tissue biopsies were obtained from 12 implants in six patients. The implants had been in function between 4 and 21 years and were, with one exception, located in the maxilla. The radiographic examination performed prior to biopsy revealed that all sites exhibited advanced bone loss. Further, clinical signs of severe inflammation, such as suppuration, swelling and/or fistula formation were detected in the majority of sites and seven of the 12 implants were found to be mobile at biopsy. Each biopsy was following fixation embedded in epoxy resin and sections were prepared for histometric and morphometric analysis.Results and conclusion: It was demonstrated (i) that all soft tissue units harbored large inflammatory cell infiltrates (ICT) that extended to a position apical of a pocket epithelium and (ii) that about 60% of the lesions were occupied by inflammatory cells, among which plasma cells dominated. Numerous amounts of PMN cells occurred not only in the pocket epithelium and adjacent connective tissue areas, but were also present in peri-vascular compartments in more central areas of the ICT.

Notes: Objective: To evaluate reactions in the oral mucosa after direct contact with CarisolvTMSetting: The Faculty of Odontology in Göteborg, Sweden. Subjects: 34 healthy persons for a clinical screening test and 35 Sprague Dawley rats for a histological study.Desing: Mixed CarisolvTM or 0.5 % NaOCl were soaked in paper and applied to either side of the medial frenula of the lower lip of 34 persons. The solutions were left on the oral mucosa for three minutes. Inspection was made and photographs were taken immediately after exposure and also after 1 hour, 24 hours, and 72 hours. Mixed CarisolvTM was applied in a similar manner as described above to 35 adult Sprague Dawley rats. The animals were killed and biopsies were taken immediately after CarisolvTM exposure and also after 1 hour, 24 hours, and 48 hours. The biopsies were sectioned and prepared for histomorphometrical evaluation in light microscopy where cells were counted on regions from the epithelium layer deeper into the mucous membrane.Results: Some adverse reactions were detected on the oral mucosa of humans up to 24 hours after CarisolvTM exposure for 3 minutes. The detected inflammatory reactions were slight and no patient felt any discomfort. The results of the histological study on rat did not show any statistically significant increase of the number of cells at any time after CarisolvTM exposure.Conclusions: If the oral mucosa gets in direct contact with CarisolvTM for 3 minutes no or only a weak inflammatory response may be expected.

Notes: Objectives: Cranial vault is widely used in experimental models on membranous bone healing in general, guided bone augmentation (GBA) studies being one example. To our knowledge, however, few studies on the characteristics of the untreated calvaria regarding bone density, vessel topography, and their intra/interindividual variations and associations are available. The aims of this investigation were to (1) map the large vessel topography of the skull vault, (2) describe the parietal bones of the adult rabbit histologically and morphometrically, and (3) histologically compare untreated parietal bone with parietal bone that had been treated with a GBA device.Material and methods: Ten adult untreated rabbits were microangiographed. General anesthesia was induced and the mediastinum was opened. Heparin and lidocaine were injected in the aorta followed by perfusion with India ink. After death, en bloc biopsies of the skull vault including the overlying soft tissues and dura mater were taken. The specimens were cleared with the Spalteholtz technique, microscopically examined, and digitally imaged. Thereafter, circular biopsies were harvested to obtain decalcified sections. In addition, sections from 14 GBA-treated rabbit skulls (of the same race, sex and age as the untreated animals) served as reference specimens for comparison. Histomorphometric examinations were carried out.Results: In the cleared specimens, all parietal bones were found to be supplied by one major branch of the meningeal artery. From each of these, separate branches supplied the dura wherein a fine vessel network covered the bone. No major vessels were found in the supracalvarial soft tissue. Numerous fine vessels were found within the periosteum and dura entering the cortical plates. The decalcified sections of the parietal bones revealed an outer and inner cortical plate enveloping a diploic space containing bone trabeculae, marrow tissue and larger sinusoids. Hollow connections were frequently found in both the outer and inner cortical plates in both the untreated and the GBA-treated specimens. These connections contained marrow tissue that extended to the periosteum and the dura. The morphometric measurements revealed similar proportions of cortical, trabecular, and marrow areas in the right and left untreated bones. The area of the outer cortical plate was significantly larger than the area of the inner cortical plate. Bone density was similar in the right and left untreated and GBA-treated specimens, as was the frequency and width of hollow connections through the cortical bone plates.Conclusions: The symmetry between the left and right parietal bones concerning the large vessel topography and the histomorphometric parameters assessed was high. Hollow connections in the cortical plates were frequently found. The bilateral use of the parietal bones is suggested to be reliable in experimental GBA models regarding the blood supply and bone quality.

Notes: The aim of the present study was to evaluate if early access to the endosteal bone compartment by removal of the outer cortical bone plate will enhance bone augmentation in a secluded space. Two titanium cylinders were placed on the skull of each of 8 rabbits. Each cylinder was placed into a circular slit, secured to the skull bone via two mini-screws and supplied with a titanium lid. On the test side, the outer plate of the cortical bone, demarcated by the slit, was removed.The subsequent bleeding resulted in blood fill of the cylinders to various degrees. On the control side, the cortical bone plate was left intact and no bleeding was observed at the time of the placement of the titanium lids. After 3 months, the animals were sacrificed to obtain histology and histomorphometry. No differences in the total amount of augmented bone tissue, in relation to the total experimental area (75.5%±10.9% at the test sites and 71.2%±13.5% at the control sites) or of the augmented mineralized bone tissue in relation to the total amount of augmented bone tissue, was revealed (17.8%±3.0% and 16.0%±4.9% respectively). There was no difference in the morphological appearance of the augmented bone between test and control sites and there were no obvious similarities in the appearance between the newly formed bone tissue and the donor bone. The augmented bone consisted of slender bone trabeculae, distributed in abundant marrow spaces. A conspicuous finding was that the bone trabeculae tended to climb along the inner walls of the titanium cylinder. It is concluded that decortication of the calvarial bone in the rabbit does not result in more bone formation beyond the skeletal envelope after a healing period of 3 months compared to no removal of the cortical bone plate inside a secluded experimental area.

Notes: The purpose of the present study was to evaluate in a rabbit model the changes in stability of implants that had been subjected to barrier membrane induced bone augmentation, as compared to untreated controls. One titanium implant was inserted in each proximal tibial metaphysis of 10 rabbits. The implants were placed in such a way that 4–5 threads on one side of the implant were left uncovered by bone. On the test side, the exposed implant surface was treated by means of a barrier membrane technique to provide for bone augmentation, while the contralateral side was untreated. The stability evaluations were made by means of resonance frequency measurements (RIM) at Day 0 and after 8, 16 and 24 weeks of healing. In addition, changes in the area of exposed implant threads were documented and measured on photographs. Removal torque measurements were performed at the day of sacrifice. In this study it was not possible to demonstrate a statistically significant better stability of implants subjected to barrier induced bone augmentation as compared to control implants still having exposed threads as evaluated by RIM and removal torque measurements.

Notes: The soft tissue response to clinically retrieved and decontaminated cover screws was evaluated in a rat model. The cover screws were cleaned by using citric acid, sterile water, hydrogen peroxide and CO2 laser alone or with a combination of these. In addition, decontaminated but not cleaned and unused cover screws were used as negative and positive controls, respectively. After cleaning the cover screws were implanted in the abdominal wall of the rat for 6 weeks. The thickness of the fibrous capsule and the number of macrophages within the capsule were measured by means of light microscopical morphometry. As compared to the negative control, CO2 laser on dry surface, CO2 laser+hydrogen peroxide and the positive control had statistically significant thinner fibrous capsules. As compared to the positive, only laser alone resulted in a similar tissue response. It is concluded that CO2 laser used alone or in combination with hydrogen peroxide may be used clinically for sufficient decontamination of titanium surfaces.

Notes: The objective of the present report was to study the effects of barrier membranes on bone resorption and implant stability in a rabbit onlay bone graft model, using resonance frequency analysis, coordinate measurements on plaster models, removal torque measurements and histology. Disc-shaped bone grafts were harvested from the calvarium and placed with titanium implants in the proximal tibial metaphyses of 9 rabbits. On one side (test) the bone graft/implant was covered by an e-PTFE barrier, while the contralateral side was not covered by a membrane and served as control. Three animals were sacrificed after 8 weeks for histology. In 6 animals the membranes were removed after 8 weeks and the animals were followed for an additional period of 16 weeks. Implant stability and bone height around the implants was assessed for the test and control sides at Day 0 and 8, 16 and 24 weeks postoperatively. Removal torque tests were performed after 24 weeks. The results showed an increase in volume of the bone graft on the test side as long as the barrier membrane was in place. However, after removal of the membrane at 8 weeks the resorption rate was higher on the test side compared to the control side, resulting in a similar bone height after 24 weeks. There were no statistically significant differences in implant stability between the test and control sides at any time point, as measured with resonance frequency analysis. Additionally, no statistically significant differences were found between the test and control sides after 24 weeks, using removal torque measurements, coordinate measurements and histomorphometric evaluation. Thus, in this experimental model, the use of non-resorbable barrier membranes did not improve the stability of implants simultaneously placed with onlay bone grafts. Moreover, extensive resorption of the grafted bone was seen after barrier removal, which resulted in similar bone graft volume for the test and control sides at the end of the observation period.

Notes: Abstract. Uncontrolled oral implant devices are still being widely used. The documentation of most oral implant systems is poorly backed up or not followed up for an adequate time period. Success rates are being quoted without reference to any defined success criteria. Frequently used oral implant designs such as the Core-Vent, IMZ and Calcitek hydroxyapatite coated implants are in neither case supported by any adequate clinical reports from minimally 5-years of follow-up. Other implant systems such as the ITI, some subperiosteal designs and the Tubingen implant demonstrate well-controlled and acceptable 5-year data but are not followed up in a sufficient number or have demonstrated less good results in the 10-year evaluation. The Small transosteal staple has been adequately reported for more than 10 years of follow-up, whereas the Branemark implant is the only endosseous design that has demonstrated acceptable 15-year success rates.

Notes: Background: If an implant with a rough surface is exposed to the oral cavity, it may accumulate greater amounts of plaque than a smooth surface, which may lead to severe problems with mucositis and peri-implantitis. The purpose of the present paper was to investigate the early inflammatory response to mucosa-penetrating abutments prepared with varying surface roughness.Methods: Nine patients had all five of their original abutments exchanged to test abutments for a 4-week period. The test abutments were prepared with five different roughnesses. The surface roughness was measured with an optical profilometer. At the end of the test period, clinical evaluation was performed; the health of the surrounding mucosa, the amount of accumulated plaque and marginal bleeding were registered. One biopsy was taken from each test abutment. Qualitative and quantitative histological evaluations were performed.Results: There was a statistically significant difference between patients regarding the amount of accumulated plaque on the abutment surfaces and inflammatory cells, but no difference between the surface modifications in relation to plaque accumulation or number of inflammatory cells.Conclusion: No relation was found between inflammatory response and abutment surface roughness after an evaluation time of 4 weeks in a human test model.