Is Metal Particle Release Associated with Peri-implant Bone Destruction? An Emerging Concept.

Peri-implant diseases affecting the surrounding structures of endosseous dental implants include peri-implant mucositis and peri-implantitis. The prevalence of peri-implantitis ranges between 15% and 20% after 10 y, highlighting the major challenge in clinical practice in the rehabilitation of dental implant patients. The widespread nature of peri-implant bone loss poses difficulties in the management of biological complications affecting the long-term success of osseointegrated implant reconstructions. Metal and titanium particles have been detected in peri-implant supporting tissues. However, it remains unclear what mechanisms could be responsible for the elicitation of particle and ion release and whether these released implant-associated materials have a local and/or systemic impact on the peri-implant soft and hard tissues. Metal particle release as a potential etiologic factor has been intensively studied in the field of orthopedics and is known to provoke aseptic loosening around arthroplasties and is associated with implant failures. In dental medicine, emerging information about metal/titanium particle release suggests that the potential impact of biomaterials at the abutment or bone interfaces may have an influence on the pathogenesis of peri-implant bone loss. This mini-review highlights current evidence of metal particle release around dental implants and future areas for research.

A classification system for loss of papillary height.

A classification system for loss of papillary height is proposed. It uses readily identifiable anatomical landmarks for reference, and sorts the degree of loss into 3 classes. The 3 broad categories allow for a quick descriptive assessment. In addition to the basic classification, it is suggested that additional and incremental description may be included to further define the defects.

Success rates of osseointegration for implants placed under sterile versus clean conditions.

A retrospective analysis was done comparing the success rate of osseointegration at stage 2 of implants placed under "sterile" versus "clean" conditions. "Sterile" surgery took place in an operating room setting with strict sterile protocol. "Clean" surgery took place in a clinic setting with the critical factor that nothing touched the surface of the implant until it contacted the prepared bone site. A total of 273 implants in 61 cases were placed under sterile conditions with a fixture success rate of 98.9% and a case success rate of 95.1%; 113 implants were placed under clean conditions in 31 cases with a fixture and case success rate of 98.2% and 93.5%, respectively as judged clinically at stage 2. The difference in the success rates was not statistically significant. The results of this analysis indicate that implant surgery can be performed under both "sterile" and "clean" conditions to achieve the same high rate of clinical osseointegration.

The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla.

This study was designed to determine whether the distance from the base of the contact area to the crest of bone could be correlated with the presence or absence of the interproximal papilla in humans. A total of 288 sites in 30 patients were examined. If a space was visible apical to the contact point, then the papilla was deemed missing; if tissue filled the embrasure space, the papilla was considered to be present. The results showed that when the measurement from the contact point to the crest of bone was 5 mm or less, the papilla was present almost 100% of the time. When the distance was 6 mm, the papilla was present 56% of the time, and when the distance was 7 mm or more, the papilla was present 27% of the time or less.

Factors affecting implant mobility at placement and integration of mobile implants at uncovering.

This study examined 1) factors that contributed to implant stability at placement and 2) the likelihood for an implant that was mobile at placement to osseointegrate. Eighty-one (3.1%) of 2,641 implants placed by the Dental Implant Clinical Research Group between 1991 and 1995 were found to be mobile at placement. Seventy-six (93.8%) of the 81 mobile implants were integrated at uncovering compared to 97.5% for the 2,560 immobile implants. Variables that influenced mobility at placement included patient age, implant design and material, anterior-posterior jaw location, bone density, and use of a bone tap. Hydroxyapatite (HA)-coated implants were slightly more likely to be mobile at placement (P = 0.324) than non-hydroxypatite (HA)-coated implants. Of the 54 HA-coated implants that were mobile at placement, all (100%) integrated, while only 17 (81.5%) of the 22 mobile non-HA-coated implants integrated (P = 0.003). Mean electronic mobility testing device values (PTVs) at uncovering for all implants mobile or immobile at placement that integrated were -2.9 and -3.6 respectively. PTVs for HA-coated implants that were mobile (-3.5 PTV) or immobile (-4.0 PTV) at placement differed by 0.5 PTV, whereas non-HA-coated implants exhibited a greater difference of 1.2 PTVs at uncovering. HA-coated implants, regardless of mobility at placement, integrated more frequently and exhibited greater stability than non HA-coated implants.

The effect of inter-implant distance on the height of inter-implant bone crest.

BACKGROUND: The biologic width around implants has been well documented in the literature. Once an implant is uncovered, vertical bone loss of 1.5 to 2 mm is evidenced apical to the newly established implant-abutment interface. The purpose of this study was to evaluate the lateral dimension of the bone loss at the implant-abutment interface and to determine if this lateral dimension has an effect on the height of the crest of bone between adjacent implants separated by different distances. METHODS: Radiographic measurements were taken in 36 patients who had 2 adjacent implants present. Lateral bone loss was measured from the crest of bone to the implant surface. In addition, the crestal bone loss was also measured from a line drawn between the tops of the adjacent implants. The data were divided into 2 groups, based on the inter-implant distance at the implant shoulder. RESULTS: The results demonstrated that the lateral bone loss was 1.34 mm from the mesial implant shoulder and 1.40 mm from the distal implant shoulder between the adjacent implants. In addition, the crestal bone loss for implants with a greater than 3 mm distance between them was 0.45 mm, while the implants that had a distance of 3 mm or less between them had a crestal bone loss of 1.04 mm. CONCLUSIONS: This study demonstrates that there is a lateral component to the bone loss around implants in addition to the more commonly discussed vertical component. The clinical significance of this phenomenon is that the increased crestal bone loss would result in an increase in the distance between the base of the contact point of the adjacent crowns and the crest of bone. This could determine whether the papilla was present or absent between 2 implants as has previously been reported between 2 teeth. Selective utilization of implants with a smaller diameter at the implant-abutment interface may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3 mm of bone can be retained between them at the implant-abutment level.

Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region.

BACKGROUND: The regeneration of gingival papillae after single-implant treatment is an area of current investigation. This study was designed to determine: 1) whether the distance from the base of the contact point to the crest of the bone would correlate with the presence or absence of interproximal papillae adjacent to single-tooth implants, and 2) whether the surgical technique at uncovering influences the outcome. METHODS: A clinical and radiographic retrospective evaluation of the papilla level around single dental implants and their adjacent teeth was performed in the anterior maxilla in 26 patients restored with 27 implants. Six months after insertion, 17 implants were uncovered with a standard technique, while 10 implants were uncovered with a technique designed to generate papilla-like formation around dental implants. Fifty-two papillae were available for clinical and radiographic evaluation. The presence or absence of papillae was determined, and the effects of the following variables were analyzed: the influence of the 2 surgical techniques; the vertical relation between the papilla height and the crest of bone between the implant and adjacent teeth; the vertical relation between the papilla level and the contact point between the crowns of the teeth and the implant; and the distance from the contact point to the crest of bone. RESULTS: When the measurement from the contact point to the crest of bone was 5 mm or less, the papilla was present almost 100% of the time. When the distance was > or = 6 mm, the papilla was present 50% of the time or less. The mean distance between the crest of bone and the most coronal papilla level (interproximal soft tissue height) was 3.85 mm (SD = 1.04). When comparing the conventional and modified surgical technique, the relation shifted from 3.77 mm (SD = 1.01) to 4.01 mm (SD = 1.10), respectively. CONCLUSIONS: These results clearly show the influence of the bone crest on the presence or absence of papillae between implants and adjacent teeth. The data also show a positive influence for the modified surgical technique, aimed at reconstructing papillae at the implant uncovering.

Gingival recession around implants: a 1-year longitudinal prospective study.

A longitudinal study was performed, which measured the soft tissue around implants following surgery, to determine if a predictable pattern of soft tissue changes could be identified. This study evaluated 63 implants in 11 patients. Baseline measurements were recorded at stage 2 surgery in 2-stage implant systems, and at stage 1 surgery in the 1-stage system. Subsequent measurements were recorded at 1 week, 1 month, 3 months, 6 months, 9 months, and 1 year after baseline measurements. The majority of the recession occurred within the first 3 months, and 80% of all sites exhibited recession on the buccal. It is therefore recommended that one wait 3 months for the tissue to stabilize before either selecting a final abutment or making a final impression. As a general rule, one can anticipate approximately 1 mm of recession from the time of abutment connection surgery. A comparison of this study's results with data recorded in previously reported studies reveals clinically significant trends in the nature of soft tissue healing.

The effect of crestal versus mucobuccal incisions on the success rate of implant osseointegration.

A retrospective analysis compared the success rate of osseointegration of Nobelpharma implants at stage 2 surgery. The implants had been placed using either a mucobuccal fold incision or a crestal incision. A total of 386 implants was placed in 92 patients; 265 implants were placed in 60 patients using a mucobuccal fold incision, with a success rate of 98.8%, and 121 implants were placed in 32 patients using a crestal incision, with a success rate of 98.3%. Implants can be placed using either a mucobuccal fold incision or a crestal incision to achieve predictable success.

Immediate loading of threaded implants at stage 1 surgery in edentulous arches: ten consecutive case reports with 1- to 5-year data.

Immediate loading of threaded implants with a fixed provisional restoration at stage 1 surgery was evaluated in 10 consecutive patients. The patients selected had to be completely edentulous and have adequate bone for a minimum of 10-mm-long implants. A minimum of 10 implants were placed in each patient's arch. A minimum of five implants were submerged initially for medicolegal reasons and allowed to heal without loading. The remaining implants were loaded the day of stage 1 surgery. Once the provisional restoration was relined, it was cemented or screw retained. A total of 107 implants were placed in these 10 patients; 6 had them placed in the mandible, and 4 in the maxilla. Six patients were treated with Nobel Biocare implants, one with ITI Bonefit implants, two with Astra Tech TiOblast implants, and one with a 31 implant. Sixty-seven of 69 implants that were loaded integrated, and 37 of 38 submerged implants integrated. All 10 patients have been restored with a definitive prosthesis, and all had a fixed provisional prosthesis from stage 1 surgery. The results of this study indicate that immediate loading of multiple implants rigidly splinted around a completely edentulous arch can be a viable treatment modality.

Modified roll technique for localized alveolar ridge augmentation.

A modification of Abram's roll technique is described. A "trap-door" approach is used to reflect and preserve the epithelium that overlies the connective tissue pedicle; the epithelial pedicle is used to cover the donor site. Two case reports illustrate the technique.

Histologic evaluation of a sinus elevation procedure: a clinical report.

A histologic assay of the grafting material associated with the sinus elevation procedure would provide insight into the quality and quantity of vital bone at the implant-bone interface. This case report documented for the first time the sequential healing process of a sinus graft in the same patient at 4, 8, 12, and 20 months. Histology of trephine-obtained core samples showed that in a sinus grafted with a mixture of xenograft (80%) and autograft (20%), 12 to 20 months was required for remodeling to vital bone. The study also demonstrated that a significant amount of vital, mature bone was generated by this procedure. Quantification of the resulting bone and comparison with other grafting techniques should be the next phase of continuing research efforts.

Histologic and clinical comparison of bilateral sinus floor elevations with and without barrier membrane placement in 12 patients: Part 3 of an ongoing prospective study.

In 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. One of the parameters under evaluation in this study is the effect of barrier membrane placement on the creation of vital bone in the grafted sinus cavity. This report presents a histologic and histomorphometric evaluation of healing with and without the placement of an expanded polytetrafluoroethylene (e-PTFE) barrier membrane over the lateral window at the time of sinus grafting. The data were collected from 12 patients who underwent bilateral sinus elevation surgery. In each of these 12 patients the same grafting material was used in both sinuses, making the presence or absence of an e-PTFE barrier membrane the only controlled variable. Under the conditions of this study, the results indicate that (1) placement of the barrier membrane tends to increase vital bone formation; (2) placement of a barrier membrane has a positive effect on implant survival; and (3) membrane placement should be considered for all sinus elevation procedures.

Sinus floor elevation using anorganic bovine bone matrix (OsteoGraf/N) with and without autogenous bone: a clinical, histologic, radiographic, and histomorphometric analysis--Part 2 of an ongoing prospective study.

One of the goals of the sinus elevation procedure is the creation of vital bone to effect the osseointegration of dental implants placed in the posterior maxilla. With this goal in mind, in 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. The primary parameters included the effects of graft material selection, time allowed for graft maturation, and the effect of barrier membrane placement on the creation of vital bone in the sinus cavity. The effects of these and other parameters on implant survival rates were also to be evaluated. This paper reports the data collected on a subgroup of 113 sinus elevations that used anorganic bovine bone matrix (OsteoGraf/N) alone or in combination with autogenous bone and/or demineralized freeze-dried bone as a graft material. This is the second in a proposed series of papers that will result from this ongoing research project. The results of this study indicate that: OsteoGraf/N appears to be an effective graft material with a 98.2% implant survival rate to date: vital bone formation increased with time; vital bone formation increased moderately when demineralized freeze-dried bone allograft was added, and increased substantially when intraoral autogenous bone was added or when an expanded polytetrafluoroethylene membrane was used; and the increased height achieved by the procedure was stable over a 3-year period. Because of the high overall implant survival rate, it was not possible to determine the relationship between vital bone formation or membrane usage and implant survival.

Human histologic evidence of integration of functionally loaded hydroxyapatite-coated implants placed simultaneously with sinus augmentation: a case report 2 1/2 years postplacement.

This article histologically and clinically presents a case report showing two retrieved implants that were placed simultaneously at the time of the antral augmentation. These implants were retrieved 2.5 years after placement and 2 years after loading. To our knowledge, this is the first human histological case report of implants that were simultaneously placed with a sinus lift and loaded.

Considerations for single-unit esthetic implant restorations.

Single-tooth replacement in contemporary dentistry is often accomplished with an osseointegrated implant-supported restoration. To accomplish this in an esthetically acceptable manner requires a thorough course of treatment, including diagnosis, treatment planning, surgery and restorative and preventive care. This article discusses surgical considerations that are applicable before implant placement, as well as at the time of stage I and II surgery. Furthermore, the interrelationship between the tissues and the restoration is addressed. Preservation of the result by preventive-care protocol is shown to be essential.

The implant periapical lesion: four case reports and review of the literature.

Postoperative complications have been identified with implant failure in conjunction with the increased use of root-type implant restorations. The failure of osseointegrated dental implants primarily occurs as a result of peri-implantitis and occlusal overload. Less frequently reported failures, however, have been attributed to implant periapical lesions. The etiology and treatment modalities for such lesions have been speculated throughout the literature. This article discusses possible etiologies of and treatment for implant periapical lesions based on the existing literature and four case reports.

Digital shade analysis and verification: a case report and discussion.

Shade analysis and selection requires the accurate and objective evaluation of hue, chroma, value, characterization, and translucency. Conventional shade analysis techniques using shade tabs often result in the subjective analysis and miscommunication of color. Digital shade analysis systems have been designed to eliminate the subjectivity of color analysis and provide exact information for laboratory buildup and fabrication. The advent of digital shade analysis can facilitate the precise and uniform fabrication of aesthetic restorations by technicians at all levels of color expertise.

A prospective 2-year clinical evaluation of overdentures attached to nonsplinted implants utilizing ERA attachments.

Edentulism is a major oral healthcare issue for an ever-increasing older population in the United States. Most previous studies examined the success of overdentures supported by splinted implants utilizing clip bars and other types of attachments. This longitudinal study of 10 consecutive patients involves mandibular overdentures supported by nonsplinted implants with ERA attachments. Two-year results indicate that nonsplinted implants can be successfully used with ERA attachments to support overdentures. Each patient reported increased satisfaction with comfort, chewing, retention, and phonetics with the implant-assisted ERA-retained overdenture.

The use of transitional implants for immediate fixed temporary prostheses in cases of implant restorations.

While the original Brånemark implant protocol has continued to evolve, the avoidance of implant loading during osseointegration remains a prerequisite with all implant systems. Immediately loaded transitional implants have recently been developed to support the fabrication of a fixed provisional prosthesis that provides implant patients with improved aesthetics and function during the osseointegration period. In this manner, osseointegration can occur free from prosthetic and transmucosal loads. This article describes the use of transitional implants and presents a classification of three different case types.