Autogenous bone graft and ePTFE membrane in the treatment of peri-implantitis. I. Clinical and radiographic observations in cynomolgus monkeys

The purpose of the study was to examine the effect of autogenous bone graft particles and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. The treatment outcome was evaluated by clinical and radiographic methods including quantitative digital subtraction radiography. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was established during 14-22 months. Plaque control was then re-implemented and surgical treatment involving autogenous bone+membrane (B+M), autogenous bone (B), membrane (M), or a conventional flap procedure alone (control) (C) was performed. The animals were killed 6 months after treatment. Healthy peri-implant tissue was established irrespective of the applied surgical procedure. A mean bone gain of 4.7 mm was identified around implants treated with B+M, while, respectively, 4.0, 3.0, and 1.9 mm were recorded within the B, M, and C groups. Quantitative digital subtraction radiography confirmed considerable bone gain within defects treated with autogenous bone with or without membrane coverage. The bone gain, especially for defects treated with B+M, seemed to be almost to the level before development of peri-implantitis. By contrast, 38 and 25% of the defect was on average characterized by bone gain when, respectively, M or C was used alone. The present study of implants with a TPS surface in cynomolgus monkeys thus demonstrates considerable bone regeneration after treatment of experimental peri-implantitis with autogenous bone graft particles with or without ePTFE membrane coverage. Further stereologic and histologic evaluation of the treatment outcome is necessary before final conclusions about the effect of autogenous bone graft and ePTFE membrane can be made.     

Autogenous bone graft and ePTFE membrane in the treatment of peri-implantitis. II. Stereologic and histologic observations in cynomolgus monkeys

The purpose of the present study was to evaluate the effect of autogenous bone graft particles and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis with stereologic and histologic methods. Clinical and radiographic findings are reported elsewhere. Experimental peri-implantitis with a bone loss of 4-6 mm was established during 14-22 months around 64 implants with a titanium plasma-sprayed (TPS) surface in eight cynomolgus monkeys (Macaca fascicularis). The defects were treated with autogenous bone+membrane (B+M), autogenous bone (B), membrane (M), or a conventional flap procedure (control) (C). The animals were killed 6 months after surgery. Healthy peri-implant tissue was established irrespective of the applied treatment procedure. However, the amount of bone (autogenous bone graft particles and regenerated bone) and re-osseointegration were significantly higher in defects treated with B+M as compared with the three other treatment modalities. A mean bone-to-implant contact of 45% was estimated within defects treated with B+M. The corresponding values for the B, M, and C groups were 22, 21, and 14%. The present study therefore demonstrates that autogenous bone graft particles covered by an ePTFE membrane is a useful surgical treatment procedure of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. Obviously, there is a background for long-term evaluation in humans.     

Anorganic porous bovine-derived bone mineral (Bio-Oss) and ePTFE membrane in the treatment of peri-implantitis in cynomolgus monkeys

The purpose of the present study was to evaluate the effect of anorganic porous bovine-derived bone mineral (Bio-Oss) and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was induced during a period of 9-18 months. Surgical treatment involving Bio-Oss+membrane, Bio-Oss, membrane, or a conventional flap procedure (control) only was carried out. The animals were sacrificed six months after treatment. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology demonstrated healthy peri-implant tissue irrespective of the applied surgical procedure. However, the amount of re-osseointegration and the total amount of bone (Bio-Oss and regenerated bone) were significantly higher in defects treated with membrane-covered Bio-Oss as compared with the other three treatment procedures. A mean bone-to-implant contact of 36% was obtained within defects treated with membrane-covered Bio-Oss. The corresponding values for the three other treatment procedures were 13-23%. The Bio-Oss particles were in general highly integrated within the regenerated bone, but the particles in the occlusal part of the defects were entirely surrounded by connective tissue irrespective of membrane coverage. The present study demonstrates that surgical treatment involving Bio-Oss covered by an ePTFE membrane is a useful treatment modality of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. However, the treatment outcome is not as encouraging as seen with membrane-covered autogenous bone graft particles documented in a study with same experimental design.     

Treatment of ligature-induced peri-implantitis by lethal photosensitization and guided bone regeneration: a preliminary histologic study in dogs

BACKGROUND: The purpose of this pilot study was to evaluate the healing potential and reosseointegration in ligature-induced peri-implantitis defects adjacent to various dental implant surfaces following lethal photosensitization. METHODS: A total of 36 dental implants with 4 different surface coatings (9 commercially pure titanium surface [CPTi]; 9 titanium plasma-sprayed [TPS]; 9 hydroxyapatite [HA]; and 9 acid-etched [AE]) were inserted in 6 male mongrel dogs 3 months after extraction of mandibular premolars. After a 2-month period of ligature-induced peri-implantitis and 12 months of natural peri-implantitis progression, only 19 dental implants remained. The dogs underwent surgical debridement of the remaining dental implant sites and lethal photosensitization by combination of toluidine blue O (100 microg/ml) and irradiation with diode laser. All exposed dental implant surfaces and bone craters were meticulously cleaned by mechanical means, submitted to photodynamic therapy, and guided bone regeneration (GBR) using expanded polytetrafluoroethylene (ePTFE) membranes. Five months later, biopsies of the implant sites were dissected and prepared for ground sectioning and analysis. RESULTS: The percentage of bone fill was HA: 48.28 +/- 15.00; TPS: 39.54 +/- 12.34; AE: 26.88 +/- 22.16; and CPTi: 26.70 +/- 16.50. The percentage of reosseointegration was TPS: 25.25 +/- 11.96; CPTi: 24.91 +/- 17.78; AE: 17.30 +/- 15.41; and HA: 15.83 +/- 9.64. CONCLUSION: These data suggest that lethal photosensitization may have potential in the treatment of peri-implantitis.     

Detoxification of endotoxin-contaminated titanium and hydroxyapatite-coated surfaces utilizing various chemotherapeutic and mechanical modalities.

The surgical repair of the ailing implant may be complicated by the surface effects of pathogenic bacteria and their products. This study evaluated the ability of various chemotherapeutic modalities to detoxify endotoxin-contaminated titanium alloy and hydroxyapatite-coated test strips. Grit-blasted titanium alloy and hydroxyapatite-coated test strips were contaminated with purified outer membranes of Escherichia coli labeled with radioactive 14C. The titanium alloy strips were treated with citric acid, stannous fluoride, tetracycline HCl, chlorhexidine gluconate, hydrogen peroxide, chloramine T, sterile water, a plastic sonic scaler tip, and an air-powder abrasive unit. Hydroxyapatite-coated strips were treated with chloramine T, citric acid, or burnished with sterile water on cotton pellets. Residual lipopolysaccharide levels were measured by liquid scintillation spectrometry. The air-powder abrasive unit removed significantly greater amounts of lipopolysaccharide than all other treatment modalities on titanium samples (P < 0.05). A 60-second burnish with sterile water was able to remove significant amounts of lipopolysaccharide when compared with untreated controls (P < 0.05). Citric acid was superior in the removal of lipopolysaccharide from hydroxyapatite-coated surfaces when compared with the controls or chloramine T (P < 0.01). Detoxification of an implant infected surface may be beneficial when surgical repair of the ailing implant is indicated.     

Re-osseointegration after treatment of peri-implantitis at different implant surfaces

Peri-implantitis is a condition that includes soft tissue inflammation and rapid loss of bone. Treatment of peri-implantitis includes both antimicrobial and bone augmenting methods. The question of whether true re-osseointegration may occur following treatment of peri-implantitis is controversial. The aim of this study was to investigate whether the character of the implant surface was of importance for the occurrence of re-osseointegration following treatment of peri-implantitis. Four beagle dogs were used. The mandibular premolars were extracted. After 12 months, 3 ITI(R) solid screw dental implants were placed in each side of the mandible. In the left side, implants with a turned surface (Turned sites) were used, while in the right side implants with a SLA surface (SLA sites) were placed. After 3 months of healing, peri-implantitis was induced by ligature placement and plaque accumulation. When about 50% of the initial bone support was lost, the ligatures were removed. Five weeks later, treatment was initiated. Each animal received tablets of Amoxicillin and Metronidazole for a period of 17 days. Three days after the start of the antibiotic regimen, one implant site (experimental site) in each quadrant was exposed to local therapy. Following flap elevation, the exposed titanium surface was cleaned with the use of cotton pellets soaked in saline. The implants were submerged. Six months later, biopsies were obtained. Treatment resulted in a 72% bone fill of the bone defects at Turned sites and 76% at SLA sites. The amount of re-osseointegration was 22% at Turned sites and 84% at SLA sites. A treatment regimen that included (i) systemic administration of antibiotics combined with (ii) granulation tissue removal and implant surface cleaning resulted in resolution of peri-implantitis and bone fill in adjacent bone defects. Further, while substantial "re-osseointegration" occurred to an implant with a rough surface (SLA), bone growth on a previously exposed smooth surface (Turned) was minimal.     

Repair of cranial bone defects with calcium phosphate ceramic implant or autogenous bone graft

Autogenous bone grafts have frequently been used in the treatment of bone defects; however, this procedure can cause clinical complications after surgery. Besides, the amount of available bone is sometimes insufficient. Therefore, synthetic biomaterials have been researched as an alternative to autogenous bone graft implants. The objective of this study was to evaluate the repair of bone defects treated with compact autogenous bone graft or porous calcium phosphate ceramics. Three defects 3 mm in diameter were produced in the skull of 21 rats. One the defects was produced in the frontal bone, which remained empty, while the others were produced in the right and left parietal bones, which were filled respectively with ceramics and autogenous bone graft. The animals were sacrificed 1, 2, 4, and 24 weeks after surgery and analyzed by light microscopy and radiography. In the twenty-fourth week, the defects filled with autogenous bone graft and ceramics had similar volumes of newly formed bone tissue. The ceramics offered favorable conditions to bone tissue growth. Thus, we concluded that the calcium phosphate ceramic implant proved to be effective in repairing defects produced in the skull of rats.     

Effects of an air-powder abrasive system on plasma-sprayed titanium implant surfaces: an in vitro evaluation

The purpose of this study was to conduct an in vitro evaluation of the effects of an air-powder abrasive system, commonly used in clinical dentistry for periodontal maintenance, on the surfaces of plasma-sprayed titanium dental implants. Twenty-eight plasma-coated titanium implant specimens were divided into a sterile water-treated control group and an air-powder-abrasive-treated test group. All specimens were subjected to three different in vitro testing conditions and post-treatment evaluations by scanning electron microscopy (SEM): (1) Topographical features of implant surfaces were studied before and after direct exposure to the abrasive; (2) biocompatibility of treated implant surfaces was evaluated and compared with those of control specimens via in vitro fibroblast attachment studies; and (3) the attachment of a common oral microbe to the implant surface and its subsequent removal by exposure to the air-powder abrasive were also evaluated. Results indicate that exposure of implant specimens to the air-powder abrasive for various periods resulted in only slight changes in surface topography, i.e., rounding of angles and edges of the plasma-spray coating and occasional surface pitting. Examination by SEM and a statistical comparison of the difference between the mean numbers of attached fibroblasts between control and test groups revealed no statistical significance. In both specimen groups, fibroblasts exhibited uniform attachment over the entire implant surface. A comparison of test and control groups demonstrated 100% removal of bacteria from the surfaces of test specimens exposed to the air-powder abrasive and approximately a 75% removal from control specimens exposed to sterile water.     

Effects of decontamination and implant surface characteristics on re-osseointegration following treatment of peri-implantitis

Background: Although considerable bone fill may occur following treatment of peri-implantitis, re-osseointegration appears to be limited and unpredictable.
Objectives: To evaluate the effects of various decontamination techniques and implant surface configurations on re-osseointegration of contaminated dental implants.
Material and methods: Three months after tooth extraction, implants consisting of a basal part and an exchangeable intraosseous implant cylinder (EIIC) were placed in the mandibles of dogs. The EIIC was machined (M), sandblasted and acid-etched (SLA), or titanium plasma sprayed (TPS). Ligature-induced peri-implantitis was initiated 8 weeks post-implantation and lasted until bone loss reached the junction of the two implant parts. Three treatment modalities were applied: (T1) the EIIC was exchanged for a pristine EIIC; (T2) the EIIC was sprayed in situ with saline; and (T3) the EIIC was removed, cleansed outside the mouth by spraying with saline, steam-sterilized, and remounted. A collagen barrier was placed over each fixture, and 3 months later, samples were processed for histology and histomorphometry.
Results: T2 revealed the highest bone-to-implant contact (BIC) level (significantly better than T1 and T3). T2 also yielded the highest bone crest level (significantly better than T1), followed by T3 (significantly better than T1). SLA showed the highest BIC level (significantly better than M), followed by TPS. There were no statistically significant differences in bone crest height between implant types.
Conclusions: Both SLA implants and in situ cleansing resulted in the best re-osseointegration and bone fill of previously contaminated implants.     

Attempts to obtain re-osseointegration following experimental peri-implantitis in dogs

The purpose of this study was to examine the healing potential and re-osseointegration in peri-implant infection defects adjacent to various implant surfaces. In 7 female Beagle dogs, a total of 41 titanium oral implants (ITI, Straumann, Waldenburg; Switzerland) with a sink depth of 6 mm (diameter 2.8 mm) were placed transmucosally. Four different surface configurations (TPS: titanium plasma sprayed (10); SLA: sand blasted and acid-etched (13); M: machined and smooth (11); TPS furc.: titanium plasma sprayed with coronally placed perforation to mimic a furcation (7) were distributed among the animals and locations. Following a healing period of 3 months, silk ligatures were placed and oral cleaning procedures abolished for 4 months to induce a vertical bone loss of about 40%. Following mechanical and chemical cleansing (chlorhexidine and metronidazole) and disinfection, the lesions were either sham operated (11) or subjected to a GTR procedure using ePTFE (30). After 6 months of healing the animals were killed and the jaws histologically evaluated. Six membranes were lost TPS: (1); SLA: (2); M: (2); TPS furc: (1) and 3 membranes exposed TPS: (1); M: (2) and excluded from further evaluation. Owing to the loss of 1 implant and infection of the membranes in the TPS furc group, this implant configuration was discarded from further analysis. For TPS surfaces, bone fill was 2.6 mm (73% of the distance from the bottom of the defect to the shoulder of the implant) sites with (4 GTR) and 0.33 mm (14%) for sites without membrane (2 controls). Re-osseointegration was 0.5 mm (14%) in the test group and 0.3 mm (14%) in the control. For SLA surfaces bone fill was 2.3 mm (83%) for sites with (7 GTR) and 0.41 mm (15%) for sites without membranes (4 controls). Re-osseointegration was 0.6 mm (20%) and 0.3 mm (11%) respectively. Corresponding values for M surfaces were 2.2 mm (62%) with 4 GTR) and 0.82 mm (31%) without membranes. Re-osseointegration was 0.07 mm (2%) and 0.19 mm (7%) respectively. This study has documented that peri-implant infections defects may heal with bone fill provided that the infection is controlled through effective antibacterial therapy. However, true reosseointegration appears to be difficult to achieve.     

Treatment of ligature-induced peri-implantitis defects by regenerative procedures. Part II: A histometric study in dogs

The purpose of this study was to evaluate, by histometric analysis, re-osseointegration following treatment of ligature-induced peri-implantitis in dogs. Five dogs were used in this study. Their mandibular premolars (P2, P3 and P4) were first removed. After 3 additional months of healing, two titanium implants were placed on each side of the mandible. After 3 months, the abutment connection was performed and experimental peri-implantitis was induced by placing cotton ligatures in a submarginal position. Ligatures and abutments were removed after one month and the peri-implant bone defects were randomly assigned to one of the treatments: debridement, debridement plus guided-bone regeneration, debridement plus mineralized-bone graft, and debridement plus guided-bone regeneration associated with mineralized-bone graft. Five months post-treatment, the degree of bone contact with the implant surface and the bone area within the threads were measured in 12 threads, the 6 most coronal at each side of each implant. One-way analysis of variance did not reveal statistically significant differences between the treatment modalities (p > 0.05). Within the limits of the present study, it can be concluded that there is a limited possibility of re-osseointegration around implant surfaces previously exposed by ligature-induced peri-implantitis.     

Trepanation and curettage treatment for acute implant periapical lesions

Six dental implants in six patients with periapical lesions were inserted and underwent trepanation and thorough curettage. During surgery, the lesion area was irrigated with copious natural saline and chlorhexidine and the bone defects were treated with tetracycline paste. The six implants were stable and asymptomatic postoperatively. The implants were loaded after 3 months. Radiologically, the radiolucency in the apical part disappeared gradually. These prostheses have functioned satisfactorily with no further complication during the follow-up period. For cases in which small lesions initially appear soon after implant placement, trepanation and curettage of the periapical lesion without resection of the apical part of the implant or bone substitute material and/or autogenous bone grafting is an effective management option. A rapid and exact diagnosis is important for treating implant periapical lesions.     

A comparison of ePTFE membranes alone or in combination with platelet-derived growth factors and insulin-like growth factor-I or demineralized freeze-dried bone in promoting bone formation around immediate extraction socket implants.

The purpose of this study was to compare bone promotion around implants which were augmented with ePTFE membranes alone or in combination with cortical demineralized freeze-dried bone (DFDB) or the combination of platelet derived growth factor-BB (PDGF) and insulin like growth factor I (PDGF/IGF-I). Membranes were placed over titanium implants which had been inserted into fresh extraction sockets with large buccal dehiscences. Twenty-four implants were placed in 4 dogs. At 18 weeks clinical bone height measurements were taken, the animals were sacrificed, and all specimens retrieved for histologic evaluation. Clinically, a significant gain in bone levels was present in both the ePTFE membrane alone group (P < 0.005) and PTFE plus PDGF/IGF-I group (P < 0.01), but not in the PTFE plus DFDB group. Results from histometric measurements revealed an approximately 2-fold increase in the percentage of implant surface in contact with bone, area of bone adjacent to the implant surface, and in the total length of the implant surface in contact with bone in the dehiscence defects treated with ePTFE plus PDGF/IGF-I compared to the defects receiving ePTFE membranes alone (each P < 0.05). The response to the DFDB was highly variable and it did not significantly improve the efficacy of the PTFE membranes for any parameter measured. The distance from the outer surface of the new bone to the implant surface was statistically significant for ePTFE membranes alone and membranes plus PDGF/IGF-I. The results demonstrated that clinically, ePTFE membranes alone or ePTFE membranes with PDGF/IGF-I were equally effective in promoting bone growth around the implants. Histologic measurements demonstrated that sites treated with ePTFE membranes plus PDGF/IGF-I had the highest bone density compared with sites which received ePTFE membranes alone or with ePTFE membranes and DFDB. The results of this study question the use of DFDB and support the use of ePTFE membranes alone or with PDG-F-BB/IGF-I as potential methods of promoting bone formation around dental implants.     

Osseointegration of Osseotite and machined titanium implants in autogenous bone graft. A histologic and histomorphometric study in dogs

It has been shown that a roughened implant surface results in a higher percentage of bone to implant contact (%BIC) than a machined one. A modified implant surface using a dual thermo-acid etching process (Osseotite) has been introduced and evaluated clinically, mechanically and histologically. The aim of the present study was the histological evaluation of the %BIC between the Osseotite or machined surfaces and the autogenous bone graft. Twenty-two custom-made split-type 10-mm-long implants having two opposing surfaces (Osseotite and machined) were placed between the cranial and caudal dorsal iliac spine at the iliac wing of two adult mongrel dogs. An artificial bone defect was created leaving a 2 mm empty space around the coronal 5 mm of the implants, while the apical 5 mm was stabilized in the existing basal bone. The defects around the implants were filled with particulate autogenous bone graft, covered by an Osseoquest membrane, and left to heal for 5 months. All inserted implants showed a complete integration in the bone tissue. It was found that the resulting %BIC at the Osseotite surface was significantly higher than at the machined one in both regenerated (46.44+/-15.81% vs. 28.59+/-12.04%) and basal bone areas (32.32+/-15.09% vs. 17.25+/-7.40%). The findings of this study imply that the use of autogenous bone graft resulted in significantly higher %BIC values in the regenerated area than in the basal bone area itself, for both implant surfaces.     

Resolution of peri‐implantitis following treatment. An experimental study in the dog.

The aim of the present experiment was i) to study the effect of anti-microbial therapy of experimentally induced peri-implantitis lesions and ii) to assess features of bone regrowth following treatment. Four beagle dogs were used. Three titanium fixtures (Brånemark System®) were installed in each quadrant of the mandible (premolars previously extracted). Abutment connection was performed 5 months later and ligature induced break-down was initiated. The ligatures were removed when approximately 50% of the initial bone support was lost. A 3-week antibiotic regimen (amoxi-cillin and metronidazole) was initiated 1 month later. Two days after the start of the antibiotic administration, the experimental implant sites were exposed to local therapy. The abutments were removed and the exposed fixture surfaces were treated with an abrasive (pumice) administered via a rotating brush (left side) or cleaned with cotton pellets soaked in saline (right side). Cover screws were attached to the fixtures and the implants were submerged. Fluorochromes were injected intravenously 2 weeks, 4 weeks and 12 weeks after surgery. The animals were killed 7-months after surgery and block biopsies of each implant site were dissected and prepared for histological analysis. The findings of the examinations disclosed that the inflammatory lesion was resolved and new bone formation had occurred in the previous defect following antimicrobial and local therapy. The amount of “re-osseointegration” that had taken place, however, was small. Indeed, at all experimental implant sites, a thin connective tissue capsule was found to separate the implant surface from the newly formed bone.     

自体牙移植物在骨增量中的研究进展

由于外伤、感染、糖尿病、绝经后骨质疏松症等病症所引起的骨量不足、种植条件较差的现象在临床中极为普遍,骨增量技术应运而生.骨移植是最常用的骨增量技术,主要来源包括自体骨移植、同种异体骨移植、异种骨材料和人工合成骨材料.近年来,自体牙由于优越的生物相容性及易获得性,逐渐成为一种新兴骨替代材料.该文比较了近年发表的关于不同类...     

Treatment of peri-implant defects with the vertical ridge augmentation procedure: a patient report

Most clinical patient reports apply the biologic principles of guided bone regeneration, in addition to defect filling with autogenous bone grafts or bone graft substitutes, in peri-implantitis therapy. Not infrequently, sites with membrane coverage have revealed early exposure, with subsequent infections, premature membrane removal, and insufficient bone regeneration. The present patient report demonstrates another surgical approach that uses the clinical principles and soft tissue management of vertical ridge augmentation, strictly following the same surgical protocol, on previously cleaned implant surfaces. The successful outcome of this surgical approach in one patient supports the feasibility of the selected treatment method in maintaining both the implants and the prosthetic reconstruction involved with peri-implantitis.     

Submerged healing following surgical treatment of peri-implantitis: a case series

ObjECTIVES: The aim was to study a regenerative surgical treatment modality for peri-implantitis employing submerged healing. MATERIAL AND METHODS: Twelve patients, having a minimum of one osseointegrated implant with peri-implantitis, with a progressive loss of >or=3 threads (1.8 mm) following the first year of healing were involved in the study. After surgical exposure of the defect, granulomatous tissue was removed and the implant surface was treated using 3% hydrogen peroxide. The bone defects were filled with a bone substitute (Algipore), a resorbable membrane (Osseoquest) was placed over the grafted defect and a cover screw was connected to the fixture. The implant was then covered by flaps and submerged healing was allowed for 6 months. After 6 months the abutment was re-connected to the supra-structure. RESULTS: A 1-year follow-up demonstrated clinical and radiographic improvements. Probing depth was reduced by 4.2 mm and a mean defect fill of 2.3 mm was obtained. CONCLUSION: Treatment of peri-implant defects using a bone graft substitute combined with a resorbable membrane and submerged healing results in defect fill and clinical healthier situations.     

Titanium deposition after peri-implant care with the carbon dioxide laser

PURPOSE: Titanium endosseous implants are becoming increasingly important in dentistry because of their excellent long-term results. However, it has been reported that these implants may lead to higher concentrations of titanium, especially in the lungs and kidneys. The purpose of this study, therefore, was to determine whether CO2 laser-assisted decontamination of exposed implant surfaces is associated with an increase in titanium release. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants were placed. After osseointegration and second-stage surgery, peri-implantitis was induced by cotton floss ligatures for 12 weeks. Surgical treatment consisted of granulation tissue removal, including decontamination of the implant surface with 3 different methods. Twenty implants were decontaminated conventionally by an air-powder abrasive for 60 seconds. Another 20 implants were decontaminated by laser treatment alone. The last 20 implants were treated conventionally by air-powder abrasive and then lased. Four months later, fresh tissue samples of various tissues were evaluated by histologic and chemical analysis. RESULTS: Quantitative analysis indicated that titanium accumulation could be detected, especially in the spleen, liver, oral mucosa, regional lymph nodes, lung, and kidney in the beagle dog model. DISCUSSION: The concentrations found did not exceed those previously reported in the literature. CONCLUSION: These results support the hypothesis that CO2 laser-assisted therapy of ailing implants will not result in excessive titanium concentrations in tissues. Accordingly, CO2 lasers appear suitable and safe for peri-implant gingival surgery.     

Resolution of an active peri-implantitis in a chronic steroid user by bone augmentation with PepGen P-15 and a barrier membrane

Dental implant treatment can be complicated with infection. A list of possible causes includes overheating during the osteotomy, bacterial contamination from an adjacent tooth, residual bacteria from the infected tooth that previously occupied the site, bone microfractures from overloading or loading too soon, and residual space left around the implant after it is seated. Most treatments entail surgical debridement of the lesion and chemical detoxification of the apical or exposed portion of the implant surface with citric acid, tetracycline, or chlorhexidine gluconate as well as guided tissue regenerative or guided bone regenerative procedures. This article describes the case of an active labiolateral peri-implantitis from a previous infectious site at tooth 12 in a patient who was a chronic steroid user. The patient was treated with surgical debridement and no implant surface detoxification and regenerative procedures with xenograft of PepGen P-15 and an absorbable collagen membrane. The patient was advised to discontinue steroid therapy. This resulted in resolution of the associated signs and symptoms of infection and new bone formation in the radiograph. The negative effect of corticosteroids on calcium metabolism and bone regeneration is discussed. The potential implications of steroid use for implant dentistry are critically appraised, and guidelines are proposed for pre- and postoperative management that may assist in the successful implant-supported rehabilitation of this patient category.