bluuebunny/crossref_metadata_2025 huggingface dataset:
Implant therapy in periodontally compromised patients
Authors: Ellegaard B. , Baelum V. , Karring T.
Published: March 2003

The present study evaluates the outcome of implant therapy in periodontally compromised patients in need of additional functional tooth support. A total of 3 1 Astra® implants and 93 ITI Dental Implant System implants were inserted in 19 and 56 patients, respectively. The length of the implants varied between 8 and 14 mm. with 45% being 8 mm and 21% being 11 mm or more. Most implants were placed in the maxilla, predominantly in the premolar region, while less than 25% were placed in the mandible. The obser vation period ranged between 12 and 40 months for Astra® implants and between 3 and 84 months for ITI implants. At annual recall visits, 4 sites on all implants were assessed for presence of plaque, bleeding on probing, probing depth, and radiographic assessment of bone loss was performed. A total of 3 implants, all ITI implants, failed, yielding a 3‐year survival rate of 95–lOO%, depending on type of implant. After 3 years, 76–86% of all implants remained free from radiographic bone loss 2 1.5 mm. After 5 years, 55% of the ITI implants remained free from such bone loss. These results indicate that periodontally compromised patients, who have experienced a considerable loss of alveolar bony support, can be successfully treated with implants.
Delayed immediate implants: alveolar bone chamzes durinrr the healing period
Authors: Nir‐hadar Orly , Palmer Michael , Soskolne Wilfred Aubrey
Published: March 2003

Delaying the placement of immediate fixtures by 6–8 weeks after extraction of the natural dentition allows for the elimination of associated infective processes, the achievement of maximum osteoblastic activity that theoretically could help the osseointegration process and complete wound covering that simplifies the placement of grafts or membranes. This study examines the healing associated with 21 fixtures in 14 patients. The fixtures were placed into sockets 6–8 weeks after tooth extraction without the use of barrier membranes or bone substitutes. Measurements were taken immediately prior to fixture placement and 3–6 months later at the abutment placement. Alveolar bone height, the remaining socket depth and diameter and the depth to which a 3.75 mm fixture could be inserted into the socket were measured. After fixture placement the vertical and horizontal measurements from the cover screw to the surrounding alveolar bone and the distance from the cover screw to the CEJ of the adjacent tooth were recorded. All fixtures were integrated at exposure with 1 failure during the follow‐up period. The distance from the cover screw to the buccal plate decreased by a mean of 2.17 mm. There was an increase in the mean vertical bone height at all 4 surfaces. When horizontal defects were present, the mean vertical distance decreased from 2.5±0.37 mm to 0.36±0.64 mm. When horizontal defects were absent, the mean vertical distance decreased from 3.86±0.58 mm to 0.48±0.25 mm. There was also a marked decrease in the horizontal distance between the bone margin and the surface of the fixture from 1.6±l.73 mm 1 to 0.02±0.02 mm. These results indicate a strong tendency for the defects to fill‐in in the horizontal plane and for bone growth to occur in the vertical plane to the height of the cover screw. In conclusion the delayed immediate placement of fixtures has a good short‐term prognosis with bone regeneration occurring around the defect without the use of barrier membranes or bone substitutes.
Evaluation of bone healing in patients with bone grafts and endosseous implants using single photon emission tomography (SPECT)
Authors: Schliephake Henning , Berding Georg
Published: March 2003

The aim of the present study was to evaluate the healing of onlay grafts to edentulous jaws in conjunction with osseointegrated implants using single photon emission computed tomography (SPECT). In all, 24 patients were examined who had received 26 full arch onlay grafts for augmentation of extremely atrophic edentulous jaws with secondary placement of implants 21.4 weeks after grafting. 99mTechnetium‐MDP scintigrams were performed immediately after grafting. before implant placement, after implant placement and before abutment connection. Tracer accumulation was assessed semiquantitatively by calculating ratios of count densities between the up‐take over the calvarium and over the grafted jaws based on 16 regions of interest in the reconstructed tomograms corresponding to 16 possible areas of implant placement. There was a significant decrease in tracer uptake during graft healing, which was followed by a significant increase after implant placement and a subsequent decrease during implant healing. In 3 patients, infection and partial necrosis of the grafted bone occurred. In these cases, tracer uptake in areas of subsequent graft infection immediately after grafting was significantly lower compared to patients with uneventful healing as a sign of inferior graft revascularization. In 3 patients, 14 implants failed due to mobility at the time of abutment connection or loss of osseointegration within the first weeks thereafter. Significantly lower levels of tracer up‐take immediately after grafting and during graft healing were found in these areas, representing a lack of bone turnover due to decreased revascularization. These areas also showed a lower increase in tracer accumulation after implant placement due to the inferior graft quality, followed by a significant increase of periimplant bone turnover at the time of abutment connection representing inflammatory periimplant bone reaction.
Guided bone regeneration for immediate non‐submerged implant placement using bioabsorbable materials in Beagle dogs
Authors: Brunel Gérard , Benqué Edmond , Elharar Frédéric , Sansac Catherine , Duffort Jean François , Barthet Pierre , Baysse Eric , Miller Neal
Published: March 2003

The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri‐implant defects after placement of non‐submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow‐screw non‐submerged dental implants. For each animal, the coronal peri‐implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site: 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone‐to‐implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures (P>0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%. P<0.05) or sites grafted with HA (22.2%, P<0.02). Total BIC in sites treated with the HA‐membrane combination (43%) was only significantly different from sites treated with HA (P<0.10). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non‐submerged implants, although the principle of the one stage surgical approach can be maintained.
Clinical and electrophysiological assessment of inferior alveolar nerve function after lateral nerve transposition
Authors: Nocini Pier Francesco , De Santis Daniele , Fracasso Enzo , Zanette Gianpietro
Published: March 2003

Inferior alveolar nerve (IAN) transposition surgery may cause some degree of sensory impairment. Accurate and reproducible tests are mandatory to assess IAN conduction capacity following nerve transposition. In this study subjective (heat, pain and tactile‐discriminative tests) and objective (electrophysiological) assessments were performed in 10 patients receiving IAN transposition (bilaterally in 8 cases) in order to evaluate any impairment of the involved nerves one year post‐operatively. All patients reported a tingling, well‐tolerated sensation in the areas supplied by the mental nerve with no anaesthesia or burning paresthesia. Tactile discrimination was affected the most (all but 1 patient). No action potential was recorded in 4 patients' sides (23.5%); 12 sides showed a decreased nerve conduction velocity (NCV)(70.5%) and 1 side normal NCV values (6%). There was no significant difference in NCV decrease between partial and total transposition sides, if examined separately. Nerve conduction findings were related 2‐point discrimination scores, but not to changes in pain and heat sensitivity. These findings show that lateral nerve transposition, though resulting in a high percentage of minor IAN injuries, as determined by electrophysiological testing, provides a viable surgical procedure to allow implant placement in the posterior mandible without causing severe sensory complaints. Considering ethical and forensic implications, patients should be fully informed that a certain degree of nerve injury might be expected to occur from the procedure. Electrophysiological evaluation is a reliable way to assess the degree of IAN dysfunction, especially if combined with a clinical examination. Intraoperative monitoring of IAN conduction might help identify the pathogenetic mechanisms of nerve injury and the surgical steps that are most likely to harm nerve integrity.
Clinical outcome of Screw Vent implants. A 7‐year prospective follow‐up study
Authors: De Bruyn Hugo , Collaert Bruno , Lindén Ulf , Johansson Carina , Albrektsson Tomas
Published: March 2003

The clinical results of 85 Screw Vent implants are described with respect to 7‐year success. including radiographically detectable bone loss. survival and prosthetic quality. The l‐year results of the same material have been reported previously (De Bruyn et al. 1992). Implants were considered as successful when they were meeting with the success criteria proposed by the European Academy for Periodontology. From the 85 implants originally installed, 16 failed during the 7‐year interval (18.8%) 6 were unaccounted for (7%), 21 (24.7%) did not meet the success criteria yet survived and 42 implants (49.4%) were successful. The success rate was 65.2% for the mandibular and 43.5% for the maxillary implants. Implant failures were irrespective of implant length, smoking habits. prosthetic quality or oral hygiene level. From 24 patients with a corresponding number of 60 implants, radiographs were available for bone loss analysis. The mean bone loss after 7‐years was 2.92 mm (range −0.5 to 6.3); 18 out of 60 examined implants (30%) showed unacceptable radiological bone loss beyond the critical value of 2.7 mm. Implant material analysis and histomorphometric analysis of a retrieved implant are discussed. In the present clinical study, the Screw Vent implant system does not meet the success criteria proposed by the European Academy for Periodontology. The on‐going bone loss increases the risk for future implant failures and peri‐implant disease.
Comparison of bioabsorbable and bioinert membranes for guided bone regeneration around non‐submerged implants. An experimental study in the mongrel dog.
Authors: Kohal Ralf‐J. , Trejo Pedro M. , Wirsching Christian , Hürzeler Markus B.
Published: March 2003

The aim of this clinical investigation was to evaluate the effect of guided bone regeneration around non‐submerged implants using different barrier membranes. Five adult mongrel dogs were used in this investigation. After having all premolars extracted and implant osteotomies performed in the regions of the former premolars, buccal bone defects were created. Subsequently, 3 implants were placed and the defects treated with 1 of the following 3 modalities: a) guided bone regeneration using an expanded polytetrafluoroethylene membrane, b) guided bone regeneration using a bioabsorbable membrane made from a synthetic copolymer of glycolide and lactide and c) no membrane application. Following implant and membrane placement, the mucoperiosteal flaps were repositioned and tightly sutured around the neck of the implants allowing for a nonsubmerged healing. After a healing period of 6 months, the animals were sacrificed and the specimens processed for histologic evaluation. The clinical pre‐treatment defects between the different treatment groups were not statistically different (bioinert membrane group: 4.9 mm; control group: 4.8 mm; bioabsorbable membrane group: 4.5 mm). The remaining histological defects after 6 months of healing amounted to approximately 2.5 mm in the bioinert membrane group, 5.1 mm in the control group and 6.0 mm in the bioabsorbable membrane group. A significant difference was observed between the bioinert membrane group and the other 2 groups. The mineralized bone‐to‐implant contact in the bioinert membrane group was 51.5%, in the control group 46.3% and in the bioabsorbable membrane group 37.5%. The values between the bioinert membrane group and the bioabsorbable membrane group were statistically different. The results of this study indicate that bone regeneration with bioinert e‐PTFE membranes around non‐submerged implants is possible. The utilized absorbable polyglycolic/polylactid membrane did not show any bone regenerative effect and the results did not differ from the control group without membrane application.
Effects of barrier membranes on bone resorption and implant stability in onlay bone grafts. An experimental study.
Authors: Rasmusson Lars , Meredith Neil , Kahnberg Karl‐erik , Sennerby Lars
Published: March 2003

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.
Long‐term stability of jaw bone tuberosities formed by “guided tissue regeneration”
Authors: Lioubavina Natalia , Kostopoulos Lambros , Wenzel Ann , Karring Thorkild
Published: March 2003

The aim of the present study was to evaluate whether bone tuberosities produced by GTR on the lateral surface of the mandibular ramus in rats are stable on a long‐term basis. Thirty male 6‐month‐old albino rats of the Wistar strain were used in the study. Tissue flaps were elevated on the lateral aspect of the mandibular ramus. The periosteum was preserved (P+) on one side of the jaw while the bone was denuded (P−) on the other. A rigid, non‐porous oval‐shaped teflon capsule was placed on both sides with its opening facing the ramus. Six months following surgery, 10 rats were sacrificed and prepared for histology while the remaining 20 rats were subjected to a second operation during which the capsules were removed. Standardized radiographs, taken immediately before and after removal of the capsule and after 3, 6, 9 and 12 months, were subjected to planimetric measurements and subtraction radiography. Ten animals were sacrificed and prepared for histological analysis after 6 months following removal of the capsules and the remaining 10 animals after 12 months. Histology revealed that at 6 months after the placement of the capsules, 17 were completely filled with new bone. The remaining 3 capsules which were displaced exhibited only partial bone fill. The radiographic analysis revealed that after 6 months 98.6±7.6%(mean±SD) in average of the cross‐sectional area created by the capsules was filled with new bone. Within 3 months after removal of the capsules a slight resorption of the new bone had occurred, thereby reducing the area of the bone tuberosities by 4 to 8%. No further resorption of the bone tuberosities took place from 3 to 12 months. These observations indicating that new bone produced by GTR is stable on a long‐term basis, may question the general belief that non‐functional bone will resorb over time.
Osseointegration of subperiosteal implants using bovine bone substitute and various membranes
Authors: Aaboe Merete , Schou Søren , Hjørting‐Hansen Erik , Helbo Mogens , Vikjær Daniel
Published: March 2003

An earlier study revealed incomplete osseointegration of individually made titanium subperiosteal implants covered by ePTFE membranes and fixated to the rabbit tibial bone surface. In addition, the newly‐formed bone was dominated by large marrow spaces. In this subsequent study, subperiosteal implants were also fixated on the bone surface of both tibia of 9 Copenhagen White rabbits. Bio‐Oss® particles were packed densely covering the entire implant surface. One of 3 different membranes covered the implant and the particles. The membranes used were the degradable Polyglactin 910® mesh, a degradable bilayer collagen membrane and the non‐degradable ePTFE membrane. Undecalcified sections were prepared for histologic evaluation after a 12 weeks' observation period. All 18 subperiosteal implants were completely osseointegrated. In addition, the marrow spaces were reduced compared to our previous study. The Bio‐Oss® particles proved to be biocompatible and osteoconductive. The ePTFE membranes revealed neither signs of collapse nor adjacent infiltration of inflammatory cells. The Polyglactin 910 mesh and the bilayer collagen membranes collapsed slightly. There were signs of resorption of the surface of the newly‐formed bone under the degradable membranes. The cause of resorption can not be documented.
Horizontal osteotomy for reconstruction of the narrow edentulous mandible
Authors: Raghoebar Gerry M. , Batenburg Rutger H. K. , Meijer Henny J. A. , Vissink Arjan
Published: March 2003

The aim of this retrospective study was to evaluate the applicability of a horizontal osteotomy procedure for reconstruction of a narrow edentulous mandible in order to enable insertion of implants. In 7 edentulous patients a narrow inferior alveolar ridge was reconstructed with autogenous bone grafts harvested by a horizontal osteotomy procedure (mean width of the top of the alveolar crest before grafting 1.3±0.3 mm, after grafting 5.6±0.6 mm). Insertion of endosseous implants (10 Brånemark implants, 8 ITI Bonefit implants) was performed 3 months after the grafting procedure. Implant supported overdentures were fabricated 3 months after implantation. At regular time intervals a standardized clinical and a radiographic evaluation was performed. All grafted sites showed sufficient bone volume for insertion of the implants at the moment of implantation. At time of evaluation (mean 37±14.6 months, range 14–68 months) all implants and overdentures functioned well. None of the patients showed a disturbed sensitivity of the lip or chin region. It is concluded that reconstruction of a narrow edentulous mandible with autogenous bone grafts harvested by an intraoral horizontal osteotomy was shown to be a reliable preimplantology procedure with potential applicability in this group of patients.
Bone reactions adjacent to titanium implants subjected to static load
Authors: Gotfredsen Klaus , Berglundh Tord , Lindhe Jan
Published: March 2003

Abstract: The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri‐implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling were carried out during the 24‐week loading period. Biopsies were harvested and processed for ground sectioning. The sections were subjected to histological examination. No evident marginal bone loss was observed at either test or control sites. The bone density and the mineralized bone‐to‐implant contact were higher adjacent to the lateral loaded implants than at the unactivated control sites. It is suggested that the static load applied to implants in a lateral direction resulted in a structural adaptation of the peri‐implant bone.
Bone reactions adjacent to titanium implants with different surface characteristics subjected to static load. A study in the dog (II)
Authors: Gotfredsen Klaus , Berglundh Tord , Lindhe Jan
Published: March 2003

Abstract: The purpose of the present study was to compare bone reactions adjacent to titanium implants with either a titanium plasma‐sprayed (TPS) or a machined surface subjected to lateral static loading induced by an expansion force. In 3 labrador dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. 12 weeks later, 2 implants with a TPS surface were placed in one side and 2 implants with a machined surface were placed in the contralateral side. Twelve weeks after implant installation, crowns, connected in pairs with orthodontic expansion screws, were fitted to the implants and a 0.6 mm wide expansion was initiated. Clinical registrations, standardized radiographs and fluorochrome labeling were carried out during a 24‐week period of loading. Biopsies with the implants in situ were harvested and processed for ground sectioning. The sections were subjected to histologic and histometric examination. A higher marginal bone level was observed around implants with a TPS surface compared to machined implants. Furthermore, the values describing the amount of bone‐to‐implant contact at the bone/implant interface as well as the density of the peri‐implant bone were lower at the machined than at the TPS implants.
Migration of osteoblastic cells on various guided bone regeneration membranes
Authors: Takata Takashi , Miyauchi Mutsumi , Wang Hom‐Lay
Published: March 2003

Abstract: To evaluate the biological effects of guided bone regeneration (GBR) barrier materials on osteoblastic cell migration, migration of mouse osteoprogenitor cells (MC3T3‐E1) was examined, in vitro, on various membranes. Eight commercially available GBR membranes – bovine type I collagen (BioMend®; BM), porcine type I collagen (BioGide®; BG), bovine type I atelocollagen (Tissue Guide®; TG), polylactic acid (Epi‐Guide®; EG), co‐polymer of polylactic acid and polyglycolic acid (Resolute®; RL, Resolut XT®; RL‐XT), expanded polytetrafluoroethylene (e‐PTFE; Gore Tex®; GT) and co‐polymer of cellulose acetate and nitrocellulose (Millipore filter®; MP) – were tested. A 3×5 mm section of the membrane was fixed to the bottom of a culture dish with double‐sided adhesive tape, and half of the membrane was closely covered by PARAFILM® (American National CanTM) to leave an unexposed area for cell migration. The border between exposed and unexposed areas was marked as a baseline of cell migration. Membranes were then plated with 3 ml of cell suspension at an initial density of 1×105 cells/ml in α‐MEM culture medium with 10% fetal bovine serum and ascorbic acid. After a 5‐hour incubation, non‐attached cells were completely washed out with phosphate buffered saline and the PARAFILM® cover was removed. After 3 days cultivation, specimens were fixed with 10% buffered formalin and stained briefly with hematoxylin. The area of cell migration on a membrane was analyzed using a LA 500 Image Analysis System and migration area per unit length of the baseline (mm2/mm) was compared among membranes. Results demonstrated that cell migration was greater in the order: RL>RL‐XT, BM, TG, MP>EG, BG. Membranes except for BG, EG and GT showed the migration rate equal to or higher than a plastic culture cover slip (Celldesk®) (P<0.01) on which cells generally grow favorably. Only a small number of the cells attached to GT, and the net cell migration for the membrane could not be determined. These results indicate that GBR barrier materials per se may influence the process of bone regeneration in vivo through the effects of their presence on cell migration.
Peri‐implant health around screw‐shaped c.p. titanium machined implants in partially edentulous patients with or without ongoing periodontitis
Authors: Quirynen Marc , Peeters Wouter , Steenberghe Daniel van , Naert Ignace , Coucke Wim , Van Steenberghe D.
Published: March 2003

Abstract: The relationship between periodontitis and peri‐implantitis remains a matter of debate. The present study compared, “within” randomly chosen partially edentulous patients (n=84 subjects, 97 jaws), the marginal bone loss around teeth and implants during 5 years (range 3 to 11 years) following the first year of bone remodelling. The patients had all been rehabilitated by means of screw‐shape c.p. titanium implants with a machined surface (Brånemark system®). During the 5 years observation interval, periodontal parameters (marginal bone and attachment loss, the latter for teeth only) were collected together with data on confounding factors (smoking, oral hygiene, tooth loss). Marginal bone loss was measured through long‐cone intra‐oral radiographs. The mean “interval” bone loss was significantly (P=0.0001) higher around teeth (0.48±0.95 mm) than around implants (0.09±0.28 mm). The corresponding data for the “worst” performing tooth (0.99±1.25 mm) and implant (0.19±0.32 mm) per subject showed the same tendency. Neither attachment nor bone loss around teeth correlated with marginal bone loss around implants. This study indicated that the rate of bone loss around screw‐shape c.p. titanium implants with a machined surface (Brånemark system® implants) was not influenced by the progression rate of periodontal destruction around the remaining teeth within the same jaw.
Probing around implants and teeth with healthy or inflamed peri‐implant mucosa/gingiva
Authors: Schou Søren , Holmstrup Palle , Stoltze Kaj , Hjørting‐Hansen Erik , Fiehn Nils‐Erik , Skovgaard Lene Theil
Published: March 2003

Abstract: The purpose of this study was to obtain a better understanding of probing measurements around osseointegrated oral implants. A comparison was made of probe tip position around Astra Tech implants and teeth of eight cynomolgus monkeys (Macaca fascicularis) in conditions of i) healthy peri‐implant mucosa/gingiva, ii) mild mucositis/gingivitis, iii) severe mucositis/gingivitis or iv) peri‐implantitis/periodontitis. Histological sections of 128 probes that were attached to implants or teeth with surrounding tissues were prepared by the cutting‐grinding technique. No systematic differences were identified in the clinical and histological estimates of the distance between the mucosal/gingival margin and the probe tip. The differences were mainly smaller than 0.5 mm, and in no case were they larger than 0.7 mm. For implants and teeth with healthy peri‐implant mucosa/gingiva, the distance between the probe tip and the alveolar bone was similar and ranged from 0.5 to 1.5 mm (P = 0.97). However, the probe tip was closer to bone around implants than around teeth in conditions of mild mucositis/gingivitis (P = 0.034), severe mucositis/gingivitis (P ≤ 0.0001) and peri‐implantitis/periodontitis (P ≤ 0.0001). Around implants with severe mucositis and peri‐implantitis, the distance was generally smaller than 0.5 mm, whereas teeth with severe gingivitis and periodontitis showed distances that mainly ranged from 0.5 to 1.5 mm. In conclusion, the probing measurements around osseointegrated oral implants and teeth were different. Even mild marginal inflammation was associated with deeper probe penetration around implants in comparison to teeth.
Vertical distraction of the severely resorbed edentulous mandible
Authors: Raghoebar Gerry M. , Liem Robert S. B. , Vissink Arjan
Published: March 2003

Abstract: The aim of this study was to evaluate the clinical and histomorphological results of distraction of the severely resorbed edentulous mandible. In a group of 10 edentulous patients suffering from insufficient retention of their mandibular denture related to a severely resorbed mandible, the anterior segment was augmented as a preimplant surgical procedure using the nonvoluminous Groningen Distraction Device (GDD). Two months after the last day of distraction, a bone biopsy was taken with a trephine, both distraction screws were replaced by endosseous implants and the guide screw was removed. The biopsies were examined by means of light microscopy (LM) and transmission electron microscopy (TEM). Radiographical and histomorphological examination of the biopsies revealed the presence of two cortical zones, one at each end of the biopsies, a poorly mineralized, fibrous interzone in the middle of the distraction gap, and two zones of mineralization between the central fibrous and the peripheral cortical zones. Formation of lamellar bone parallel to the distraction vector was clearly visible in the mineralization zone as well as signs of remodelling at the borderline between the native cortical bone and the generate. Clinical examination showed in all patients that the anterior segment distracted from the mandible body was sufficiently enlarged to enable insertion of endosseous implants with a length of at least 12 mm. One implant was lost during the healing phase, but was successfully replaced thereafter. Implant retained overdentures were fabricated 3 months after implantation. All patients have good function 11.2 ± 4.3 months after the end of treatment. From this study it is concluded that the GDD has proven to be a reliable tool for augmentation of the anterior segment of a severely resorbed edentulous mandible enabling osseointegration of endosseous load‐bearing implants.
Computer‐enhanced stereoscopic vision in a head‐mounted display for oral implant surgery
Authors: Wanschitz Felix , Birkfellner Wolfgang , Figl Michael , Patruta Sanda , Wagner Arne , Watzinger Franz , Yerit Kaan , Schicho Kurt , Hanel Rudolf , Kainberger Franz , Imhof Herwig , Bergmann H. , Ewers Rolf
Published: March 2003

Abstract: We developed a head‐mounted display (HMD) with integrated computer‐generated stereoscopic projection of target structures and integrated it into visit, a specific oral implant planning and navigation software. The HMD is equipped with two miniature computer monitors that project computer‐generated graphics stereoscopically into the optical path. Its position is tracked by the navigation system's optical tracker and target structures are displayed in their true position over the operation site. In order to test this system's accuracy and spatial perception of the viewer, five interforaminal implants in three dry human mandibles were planned with visit and executed using the stereoscopic projection through the HMD. The deviation between planned and achieved position of the implants was measured on corresponding computed tomography (CT) scan images recorded post‐operatively. The deviation between planned and achieved implant position at the jaw crest was 0.57 ± 0.49 mm measured from the lingual, and 0.58 ± 0.4 mm measured from the buccal cortex. At the tip of the implants the deviation was 0.77 ± 0.63 mm at the lingual and 0.79 ± 0.71 mm at the buccal cortex. The mean angular deviation between planned and executed implant position was 3.55 ± 2.07 degrees. The present in vitro experiment indicates that the concept of preoperative planning and transfer to the operative field by an HMD allows us to achieve an average precision within 1 mm (range up to 3 mm) of the implant position and within 3° deviation for the implant inclination (range up to 10°). Control during the drilling procedure is significantly improved by stereoscopic vision through the HMD resulting in a more accurate inclination of the implants.
Anatomic site evaluation of the zygomatic bone for dental implant placement
Authors: Nkenke Emeka , Hahn Michael , Lell Michael , Wiltfang Jörg , Schultze‐Mosgau Stefan , Stech Beate , Radespiel‐Tröger Martin , Neukam Friedrich Wilhelm
Published: March 2003

Abstract: Thirty human zygomatic bone specimens (15 females mean age 81.60 ± 11.38 years, 15 males, mean age 78.47 ± 6.58 years) were examined by quantitative computed tomography and histomorphometry. The aim of the study was to assess the bone mineral density, the trabecular bone volume and the trabecular bone pattern factor. Moreover, the anterior‐posterior and the medio‐lateral dimensions and the estimated implant length within the zygomatic bone were determined. For quantitative computed tomography the specimens were scanned together with a bone mimicking anthropomorphic reference phantom. The bone mineral density was calculated for the specimens in the plane of the intended direction of the implant placement. Subsequently, with the sawing and grinding technique, the specimens were prepared in the same plane for histomorphometry. The trabecular bone mineral density was 369.95 ± 188.80 mg/cm3 for the female and 398.94 ± 99.11 mg/cm3 for the male specimens (P = 0.23). The male trabecular bone volume showed a value of 27.32 ± 9.49%, while the female group reached a value of 19.99 ± 7.60% (P = 0.23). The trabecular bone pattern factor was 1.2 × 10−2 ± 1.28 mm−1 for the male and 1.02 ± 0.96 mm−1 for the female specimens (P = 0.045). The study reveals that the zygomatic bone consists of trabecular bone with parameters that are unfavourable for implant placement. However, the success of implants placed in the zygomatic bone is secured by the employment of at least four cortical portions.
Leukocyte functions in 2 cases of Papillon‐Lefèvre syndrome
Authors: Liu Rongkun , Cao Caifang , Meng Huanxing , Tang Zhihui
Published: March 2003

Aim:

To investigate the rôle of leukocytes in the pathogenesis of Papillon‐Lefèvre syndrome (PLS).

Methods: Peripheral blood polymorphonuclear neutrophils (PMNs), monocytes (MNs) and gingival crevicular fluid (GCF) were obtained from 2 cases of PLS with typical features. The chemotaxis of PMNs and MNs were evaluated using a modified Boyden chamber. The adherence of PMNs was determined by adherence of PMNs to petri dishes. Interleukin‐8 (IL‐8) in GCF was detected by sandwich ELISA. Elastase activity in GCF was measured with a low molecular weight substrate (S‐2484) specific for granulocyte elastase.

Results: PMNs from both patients showed depressed chemotactic response to FMLP and IL‐8. Total amounts of IL‐8 in GCF from the 2 patients were much higher than those of the normal controls. Elastase activity was not significantly different from that of the controls. The adherence of PMN and the chemotaxis of MN in the 2 patients were normal.

Conclusion: The depressed chemotactic response of PMN leads to decreased recruitment of PMN and/or release of lysozyme from PMN in the diseased gingival tissue, increasing the susceptibility of PLS patients to periodontal infection.
Radiographic periodontal attachment loss as an indicator of death risk in the elderly
Authors: Soikkonen K. , Wolf J. , Salo T. , Tilvis R.
Published: March 2003

Objectives:

Oral infections have been associated with serious systemic diseases and an increased risk of death. Our aims were to investigate whether radiographically‐observed apical periodontitis lesions, carious teeth, periodontal attachment loss (horizontal bone loss, furcation lesions, number of teeth with infrabony periodontal pockets, the extent of infrabony periodontal pockets) and the sum of all these findings have any relationships with all‐cause mortality within 4‐year follow‐up.

Material and methods:

292 community‐dwelling elderly persons aged 76, 81 and 86 years. The number of deaths within 4 years was 54 (18.5%). In the dentate 169 subjects, of whom 32 (18.9%) deceased within 4 years, the mean number of teeth was 15.5 in men and 13.2 in women. The imaging method used was panoramic radiography supplemented by intraoral radiographs.

Results: 51% of the dentate subjects had infrabony pockets (mean 1.5, s.d. 2.2), and 40% had periapical periodontitis lesions (mean 1.0, s.d. 1.6). After controlling for age and gender, vertical bone loss judged as advanced infrabony pockets was associated with 4‐year all‐cause mortality (Odds ratio 2.2,1.0–4.7). Other associations were statistically insignificant.

Conclusion: Periodontal attachment loss may indicate an increased risk of death in the elderly.
Increased amounts of laminin in GCF from untreated patients with periodontitis
Authors: Figueredo C. M. S. , Gustafsson A.
Published: March 2003

Background/aims: Our aim was to compare the levels of laminin and interleukin‐8 (IL‐8) in GCF from inflamed shallow (GP) and deep pockets (PP) in patients with periodontitis to these levels in GCF from inflamed shallow pockets (GG) in subjects with gingivitis alone.

Method: Lactoferrin was used as a marker for the number of neutrophils in the sites sampled. The periodontitis group consisted of 13 subjects, having at least 6 sites with a pocket depth 5 mm. The healthy control group consisted of 12 subjects with no clinical signs of periodontal destruction. GCF was collected with paper strips and the volume was measured immediately after sampling. Laminin, lactoferrin and IL‐8 were measured using specific antibodies with an ELISA.

Results: The total amount of laminin was significantly higher in PP than in GG, but no significant difference was seen between GP and PP. The concentration and the total amounts of lactoferrin were similar in the three groups. The ratio between laminin and lactoferrin was higher in the samples from the patient, suggesting that neutrophils in patients are more activated and degrades more of the membrane per cell. The total amounts of IL‐8 were very similar in the 3 groups, while the concentration also tended to be higher in the GP.

Conclusions: Our study showed higher amounts of laminin in GCF from patients with periodontitis suggesting the presence of hyperactive neutrophils during the transmigration process through the endothelium/epithelium.
Topical metronidazole application as an adjunct to scaling and root planing
Authors: Stelzel Michael , Florès‐de‐Jacoby Lavin
Published: March 2003

Aim: This study was carried out to investigate the effect of 2 applications of a metronidazole 25% dental gel as adjunctive therapy to subgingival scaling with root planing.

Method: 59 of the original collective of 64 patients with adult periodontitis were observed for a 9‐month period. This randomised single‐blind study was carried out in split‐mouth design. Each patient had to have at least 2 pockets with a probing depth of 5 mm in each quadrant. The clinical parameters, pocket probing depth (PPD), attachment level (AL) and bleeding on probing (BOP), were recorded at all teeth on days 0, 91, 175 and 259; in addition, subgingival plaque samples taken from 45 patients were analysed by means of dark‐field microscopy. Therapy comprised subgingival scaling and root planing (SRP) of all quadrants and additional application of metronidazole 25% dental gel in 2 randomly selected quadrants (SRP+Metro). Treatment was confined to teeth with a baseline PPD of 5 mm. Average PPD and AL and the incidence of BOP were computed for all pockets with a baseline PPD of 5 mm, and the 2 methods compared. The main efficacy variable for evaluation of the 2 treatments was the difference in PPD on day 259.

Results: Comparison of the 2 treatments revealed a statistically significant improvement in the clinical parameters for both treatment methods over the study period. Between baseline and day 259, significant differences in PPD (SRP+Metro: from 6.00 to 4.63 mm, SRP: from 6.02 to 4.83 mm) and BOP (SRP+Metro: from 67 to 31%, SRP: from 64 to 36%) were observed between the 2 treatment groups. Evaluation according to different patient groups demonstrated significant advantages of the combined therapy in previously‐untreated patients, especially in female probands. Dark‐field microscopy revealed a shift in the bacterial flora towards “healthy conditions”.

Conclusions: The results show that only minor advantages are to be gained from the application of a metronidazole 25% dental gel as adjunctive therapy to subgingival scaling. The distinctly better results of combined therapy in previously‐untreated patients calls for more thorough investigation.
Actinobacillus actinomycetemcomitans‐associated peri‐implantitis in an edentulous patient
Authors: Van Winkelhoff A. J. , Wolf J. W. A.
Published: March 2003

Background: Peri‐implantitis is a risk factor for implant loss. Late bacterial infection of the peri‐implant tissues and loss of alveolar bone in edentulous patients is caused by commensal oral anaerobic bacteria. In partially edentulous patients, Porphyromonas gingivalis and occasionally Actinobacillus actinomycetemcomitans are associated with peri‐implantitis lesions.

Aims: To investigate the microbiology of a peri‐implantitis case in an edentulous patient.

Methods: Anaerobic culture techniques and selective culture techniques for A. actinomycetemcomitans were used to study the peri‐implant microflora at sites with and without bone loss.

Results: An anaerobic peri‐implant microflora with several putative periodontal pathogens was found at sites with bone loss. Furthermore, a metronidazole‐resistant A. actinomycetemcomitans was isolated. The A. actinomycetemcomitans infection did not respond to systemic doxycycline therapy, despite good susceptibility in vitro.

Conclusions: The present case of severe A. actinomycetemcomitans‐associated peri‐implantitis shows the importance of pre‐operative infection control. The findings in this case show that remaining teeth affected by periodontitis can be a serious risk factor for peri‐implantitis.
Chemokine RANTES in gingival crevicular fluid of adult patients with periodontitis
Authors: Gamonal J. , Bascones A. , Jorge O. , Silva A.
Published: March 2003

Background, aims: This study presents the first evidence on the presence of the chemokine RANTES in the gingival fluid crevicular (GCF) of patients with periodontitis. RANTES is a chemokine that selectively attracts and activates macrophages and lymphocytes. Leucocytes play a critical rôle in the host response to the subgingival microflora.

Method: In this study, the presence de RANTES in GCF was determined in samples obtained from adult patients with periodontitis and from control subjects with clinically healthy gingiva. GCF was collected from different probing depths (<3 mm, 4–6 mm, >6 mm) (n=72); and active (n=12) and inactive sites (n=12). An active site was defined as attachment loss >2 mm, as determined by sequential probing and the tolerance method. GFC was collected for 30 s using Periopaper® strips, and RANTES was quantified by ELISA.

Results: The presence of RANTES was detected exclusively in the group of patients with periodontitis, presenting a total amount of 40.43±16 pg and a concentration 67.80±41 pg/μl. RANTES concentration was significantly higher in probing depth <3 mm than in probing depth >6 mm (87.24 versus 51.87, p=0.014). Total amount and concentration in the GCF samples from active sites were higher that in inactive sites (p>0.05).

Conclusions: The finding that RANTES is found only in patients with periodontitis, may represent a general feature of chronic inflammatory in periodontal diseases. Finally, RANTES may be implicated in the biological mechanisms underlying the pathogenesis and progression of periodontal disease.
Humoral immunity host factors in subjects with failing or successful titanium dental implants
Authors: Kronström Mats , Svensson Björn , Erickson Eve , Houston Laura , Braham Pamela , Persson G. Rutger
Published: March 2003

Background: Treatment with titanium dental implants is in general successful. However, an unknown number of implants do not integrate and are removed either by exfoliation or at the time of second stage surgery. It would be of importance to identify subjects at risk and predict early implant failure.

Methods: In a retrospective study serum IgG antibody titers and avidity in sera from 40 subjects who had experienced titanium dental implant treatments with non‐osseo‐integration as the outcome (NOTI) and in sera from 40 age and gender matched control subjects who had received successful titanium dental implants (SOTI) were studied. Serum IgG titers to whole cell Actinomyces viscosus, Bacteroides forsythus, Porphyromonas gingivalis, Staphylococcus aureus, and Streptococcus intermedius sonicated antigen preparations were studied by ELISA.

Results: Serum IgG antibody titers to S. aureus were significantly higher in subjects with SOTI than in NOTI (p<0.001) suggesting that higher titers indicate protection against implant failure as a result of S. aureus infection. Statistically significant higher serum IgG antibody avidity to P. gingivalis and B. forsythus were found in subjects with SOTI than in subjects with NOTI (p<0.01 and p<0.001, respectively). Statistical analysis failed to demonstrate antibody titer or avidity differences to the other pathogens studied. The likelihood that SOTI was associated with a high OD reading for S. aureus was 13.1:1 (p<0.001). Whether subjects were edentulous or not, or if they had lost teeth because of periodontitis or caries did not seem to matter.

Conclusion: Serum IgG antibodies relative to B. forsythus, P. gingivalis and S. aureus may be associated with the outcome of implant procedures and explain why early implant failures occur.