Endosseous dental implantology from the periodontist's viewpoint.

Oral implantology has been a controversial dental therapeutic procedure for many years. Periodontics, as a specialty, did not really get involved until the word, osseointegration, was placed in the implant nomenclature by Dr. Per-Ingvar Branemark and the attendant success rate for osseointegrated prostheses was presented in a fully documented format. In March 1985, the definition of the scope of periodontics was provisionally changed by the Executive Council of the American Academy of Periodontology to include the discipline of oral implantology. Requirements for Advanced Specialty Education Programs in Periodontics with an effective date of January 1, 1986, include a statement as to the desirability of including implantology in some form in the postdoctoral curriculum. Many implant materials and designs are presently being used in endosseous dental implantology; studies are in progress to evaluate the short- and long-term response of hard and soft tissues to these materials. Continuing, nonbiased research is needed to fully understand and use this promising modality.

Dental implants: a review.

The present article is a review presenting an update on the field of dental implants since the World Workshop in Clinical Periodontics in July 1989. Areas that are discussed include following: 1. Biomaterials and the implant interface, and the interaction of these with the environment. 2. Periodontal considerations including data supporting a perimucosal seal of implant to soft tissue and discussion of the endosseous interface between the bone and the implant. 3. Newer techniques of diagnostic imaging and their determination of bone types are related to the future practice of dental implants. 4. Implant selection and the surgical techniques involved in implant placement. 5. Current ideas of implant prosthodontics, implant maintenance, and the treatment of implant failures. 6. Finally, the use of dental implants in the United States and Sweden.

Hydroxylapatite as an alloplastic graft in the treatment of human periodontal osseous defects.

Twelve patients, 32 to 60 years of age, received a polycrystalline ceramic form of pure dense hydroxylapatite as an alloplastic bone implant material in intrabony defects following reflection of full mucoperiosteal flaps, root planing and defect-curettement. The defects were measured from an acrylic stent, using an endodontic silver point which was placed to the base of the defect. Similarly, debrided and curetted defects in the same patients were not implanted and served as controls. Recalls for documentation and plaque control were at 1, 2, and 4 weeks, and at 3, 6 and 9 months. Measurements relating to changes in defect-depth were made upon reentry at 9 months. The twelve defects, serving as controls, showed very little difference between the pretherapy and 9-month measurements. The initial mean measurement from the base of the defect to the highest alveolar crest was 4.27 mm and the 9-month mean measurement after curettage only was 3.36 mm. In terms of resolution of the original defect this amounted to 19.49% reduction, but a 0.46-mm mean loss in height of the alveolar crest provided an actual percentage fill of the original defect of 9.91%. Of sixteen experimental defects, the same initial mean measurement from the base of the defect to the highest alveolar crest was 5.18 mm and the 9-month mean measurement after grafting was 2.43 mm. In terms of resolution of the original defect, this amounted to a 53.57% reduction, but in contradistinction to the curettage sites, a mean increase in height of the highest alveolar crest of 0.61 mm gave a true percentage fill of the original defect of 66.89%. At the 9-month reentry, the implanted mass seemed to be partially "calcified" and was resistant to penetration with a probe or removal with a curette. The data and clinical impression strongly suggest that hydroxylapatite has a potential as an alloplastic implant with clinically apparent acceptance by the soft and hard tissues.

Comparison of bioactive glass to demineralized freeze-dried bone allograft in the treatment of intrabony defects around implants in the canine mandible.

BACKGROUND: The purpose of this study was to evaluate and compare the healing of different bone grafting materials adjacent to titanium plasma-sprayed (TPS) endosseous dental implants. METHODS: Implant osteotomy sites were prepared and standardized 3-walled intrabony defects (3 mm x 5 mm x 5 mm) were created at the mesial of each implant site. Thirty-two TPS implants were placed in edentulous mandibular ridges of the 4 dogs. Periodontal dressings were placed in the defect sites so as to create a defect simulating bone loss around an implant. After 3 months, the periodontal dressing was removed, the defect sites debrided and evaluated for size, and intramarrow penetration performed. The graft materials tested were 1) canine demineralized freeze-dried bone allograft (cDFDBA); 2) bioactive glass granules of a broad size range 90 to 710 microns (BRG); and 3) bioactive glass granules of narrow size range 300 to 355 microns (NRG). One site on each side of the mandible was not filled and served as a control. Dogs were sacrificed 4 months after graft placement. RESULTS: Histologically, differences in percent bone-to-implant contact in the defect area were observed between the treatment groups. cDFDBA>control=BRG=NRG with statistical significance found between cDFDBA and control (P = 0.0379), but no statistically significant difference between control or either bioactive glass material. When comparing percent bone height fill of the defect in the grafted area, cDFDBA (65.7%) was significantly better than the control (48.9%; P < or = 0.05) with no statistically significant difference between control, broad range bioactive glass (57.3%) and narrow range bioactive glass (56.6%). When total bone area was measured, the percentage of new bone in the grafted area was cDFDBA (42.1%), broad range glass (33.1%) and narrow range glass (22.6%) with significance found between cDFDBA and NRG (P = 0.0102). The content of residual graft particles in soft tissue was significant (P = 0.0304) between cDFDBA (1.4%) and NRG (11.4%) with no significant difference between graft material for residual particle content in bone tissue. CONCLUSIONS: The results of this study indicate that percent bone-to-implant contact and percent bone height fill in an intrabony defect around titanium plasma-sprayed implants are statistically significantly higher with the use of DFDBA when compared to bioactive glass material.

Clinical evaluation of wound healing following multiple exposures to enamel matrix protein derivative in the treatment of intrabony periodontal defects.

BACKGROUND: Multiple exposures to enamel matrix protein derivative (EMD) during periodontal therapy have been shown to be safe for the patient. The purpose of this study was to clinically determine if an altered course of wound healing would occur after multiple exposures to EMD in the treatment of intrabony defects. A secondary aim was to assess the efficacy of EMD in probing depth reduction and clinical attachment level gain. METHODS: Thirty-two systemically healthy patients (18 females, 14 males, 33 to 69 years old) who were being treated for moderate to advanced periodontal disease were selected for the study. Surgical procedures involving 2 sites were separated by at least 8 weeks, and wound healing comparisons were made between the first and second procedure. Patients were given a diary card the day of surgery, which consisted of questions concerning the presence and severity of headaches, root hypersensitivity, tooth pain, swelling, and itching. Patients were also examined at postoperative visits to clinically assess wound healing and discuss responses to the questionnaire. Soft tissue measurements were taken the day of surgery and 6 months postoperatively to ascertain probing depth reduction (PD) and gains in clinical attachment levels (CAL). RESULTS: The results revealed no clinically detectable reaction that could not be attributed to normal postoperative sequelae. There were no differences in reported symptoms between patient gender, first and second procedures, or intrabony and non-intrabony defects. Smokers were found to have a statistically significantly higher incidence of severe symptoms in root hypersensitivity, tooth pain, and swelling compared to non-smokers (n = 21). The mean probing depth reduction was 3.8 +/- 1.5 mm (2 to 9 mm), while the mean clinical attachment level gain was 2.8 +/- 1.7 mm (0 to 8 mm). CONCLUSIONS: The findings of this study demonstrate that EMD is a clinically safe product to use in the treatment of periodontal defects and that multiple uses do not have a negative impact on periodontal wound healing. In addition, a statistically significant gain in clinical attachment and reduction in probing depth were demonstrated.

Clinical evaluation of demineralized-unicortical-ilium-strips for guided tissue regeneration.

This study compared demineralized-unicortical-ilium-strips (DUIS) and an expanded polytetrafluoroethylene (ePTFE) physical barrier in combination with decalcified freeze-dried bone allograft (DFDBA) for treatment of Class II mandibular furcations. Twenty patients with adult periodontitis and at least 2 furcation invasions participated in this study. Probing depth (PD), clinical attachment level (CAL), and bone fill were measured at 6 and 12 months. Standardized radiographs were analyzed using computer assisted densitometric image analysis (CADIA). Fifteen of 20 patients completed the 12-month evaluation. At 6 months both control and test groups showed significant reductions in PD from baseline (P < 0.01). PD reduction for the ePTFE + DFDBA sites was 2.13 mm +/- 1.25, and the DUIS + DFDBA, 1.77 mm +/- 1.21. CAL at 6 months was sustained to 12 months when the net gains in CAL for ePTFE + DFDBA being 1.30 mm +/- 1.45 (P < 0.01) and for DUIS + DFDBA sites 1.13 mm +/- 1.68 (P < 0.02). The horizontal furcation PD decreased 2.87 mm +/- 1.68 (P < 0.01) in the ePTFE + DFDBA and 1.70 mm +/- 1.69 (P < 0.01) for DUIS + DFDBA sites over 12 months. The evaluation of the hard tissue response at the 12-month re-entry demonstrated a bone fill of 2.37 mm (75%) +/- 2.04 (P < 0.01) with ePTFE + DFDBA and 1.83 mm (79%) +/- 1.57 (P < 0.01) with DUIS + DFDBA. DUIS material and ePTFE showed significant improvements in clinical parameters and neither material proved to be significantly better. However, a larger sample size may have permitted us to demonstrate statistically significant differences between the materials. The positive results from the utilization of DUIS for GTR and the advantage of its bioresorbability warrant further investigation. The study found limitations in the use of CADIA for evaluation of guided tissue regeneration in furcations.

Clinical evaluation of bioactive glass in the treatment of periodontal osseous defects in humans.

The purpose of this study was to compare the use of bioactive glass to demineralized freeze-dried bone allograft (DFDBA) in the treatment of human periodontal osseous defects. Fifteen systemically healthy patients (6 males and 9 females, aged 30 to 63) with moderate to advanced adult periodontitis were selected for the study. All patients underwent initial therapy, which included scaling and root planing, oral hygiene instruction, and an occlusal adjustment when indicated, followed by re-evaluation 4 to 6 weeks later. Paired osseous defects in each subject were randomly selected to receive grafts of bioactive glass or DFDBA. Both soft and hard tissue measurements were taken the day of surgery (baseline) and at the 6-month re-entry surgery. The clinical examiner was calibrated and blinded to the surgical procedures, while the surgeon was masked to the clinical measurements. Statistical analysis was performed by using the paired Student's t test. The results indicated that probing depths were reduced by 3.07 +/- 0.80 mm with the bioactive glass and 2.60 +/- 1.40 mm with DFDBA. Sites grafted with bioactive glass resulted in 2.27 +/- 0.88 mm attachment level gain, while sites grafted with DFDBA had a 1.93 +/- 1.33 mm gain in attachment. Bioactive glass sites displayed 0.53 +/- 0.64 mm of crestal resorption and 2.73 mm bone fill. DFDBA-grafted sites experienced 0.80 +/- 0.56 mm of crestal resorption and 2.80 mm defect fill. The use of bioactive glass resulted in 61.8% bone fill and 73.33% defect resolution. DFDBA-grafted defects showed similar results, with 62.5% bone fill and 80.87% defect resolution. Both treatments provided soft and hard tissue improvements when compared to baseline (P < or = 0.0001). No statistical difference was found when comparing bioactive glass to DFDBA; however, studies with larger sample sizes may reveal true differences between the materials. This study suggests that bioactive glass is capable of producing results in the short term (6 months) similar to that of DFDBA when used in moderate to deep intrabony periodontal defects.

A proposed radiographic index for assessment of the current status of osseointegration.

The longevity of an osseointegrated implant is directly affected by the maintenance of its osseous anchorage. Progressive marginal bone loss would be detrimental to its survival. This article proposes a new radiographic index for use in the radiographic assessment of peri-implant marginal bone levels. The index scores range from 0 to 6 and denote marginal bone loss in percentages relative to the implant body length measured from its coronal-most margin in an apical direction. The proposed index should be of significance in: (1) use of short implants (7 to 10 mm); (2) evaluation of implants functioning in areas of low bone density (types 3 and 4); (3) prognosis and treatment of ailing/failing implants; (4) follow-up of implants placed in extraction sites; and (5) correlation of crown-to-implant ratio with marginal bone loss.

Light and confocal laser scanning microscopic evaluation of hydroxyapatite resorption patterns in medullary and cortical bone.

An animal study was conducted with unloaded blocks and hydroxyapatite (HA)-coated titanium implants. Four HA blocks were positioned in rabbit tibiae and four HA-coated titanium implants were positioned in pig tibiae. Implants were positioned so that half was placed in cortical bone and half in medullary space. Biopsy specimens were taken 4 months after implant placement for histologic evaluation. Light microscopy and confocal laser scanning microscopy demonstrated that the HA resorption rate was higher in the medullary spaces, whereas resorption was almost absent in the areas embedded in cortical bone.

A comparative study of the effects of metallic, nonmetallic, and sonic instrumentation on titanium abutment surfaces.

This study compared the effects of metallic, nonmetallic, and sonic instrumentation on titanium abutment surfaces in vitro. Designated test surfaces in each of seven abutments were instrumented either for 25 strokes or 30 seconds, and for 50 strokes or 5 minutes. One abutment served as an untreated control. Scanning electron microscopy photomicrographs were coded and scored by five investigators and designated as smooth (comparable to control (0), slightly roughened, (1), moderately roughened (2), or severely roughened (3). Based on this investigation, the increasing order of surface alteration for each instrumentation was as follows: Implacare < Implant Support < Steri-Oss < Dynatip < Columbia 13/14 < Sonic scaler < Implarette scaler. The Implacare and Implant Support nonmetallic (plastic) scalers appear to be the instruments of choice for debridement of titanium abutment surfaces if preservation of surface integrity is the primary objective.

Evaluation of three different dental implants in ligature-induced peri-implantitis in the beagle dog. Part II. Histology and microbiology.

The purpose of this study was to evaluate experimental peri-implant breakdown microbiologically, radiographically and histologically. Hydroxyapatite-coated, titanium plasma-sprayed, and titanium alloy surfaces were investigated. Eighty-four implants were placed in 14 beagle dogs. Standardized radiographs and microbiologic samples (DNA) were obtained. Dogs were sacrificed at 3 and 6 months. Undecalcified histologic sections were prepared. Thickness of hydroxyapatite coating, changes in crestal bone height, and marginal changes in osseointegration were measured. Vertical bone loss was computed. Radiographs were analyzed using computer-assisted densitometric image analysis (CADIA). Microbial analysis (DNA) did not clearly favor any of the examined surfaces. CADIA did not show differences among implant surfaces. No significant differences among the three implants were noted for histometry, except the experimental titanium plasma-sprayed surface showed an increase in vertical bone loss 6 months (P < .05). Thickness of hydroxyapatite was decreased in active peri-implantitis sites (P < .05). Clinical attachment level was shown to be the most sensitive clinical parameter for detecting histologic changes. All implants were equally susceptible to peri-implantitis.

Evaluation of three different dental implants in ligature-induced peri-implantitis in the beagle dog. Part I. Clinical evaluation.

The purpose of this study was to clinically evaluate experimental peri-implant breakdown. Hydroxyapatite-coated, titanium plasma-sprayed, and machined titanium-alloy surfaces were investigated. Eighty-four implants were placed in 14 beagle dogs. Pocket probing depths and clinical attachment level and mobility measurements were made. Dogs were sacrificed at 3 and 6 months. All experimental implants showed a significant loss in clinical attachment level (P < .05). Increased pocket probing depths for experimental implants occurred during the first 2 months, after which a plateau was reached. At the 3- and 6-month evaluation, pocket probing depths at experimental implants were significantly increased (P < .05). No differences among the three implant types were noted for clinical attachment levels and pocket probing depths. In general, greater mobility was found with the titanium-alloy implants than with hydroxyapatite-coated and titanium plasma-sprayed implants (P < .025). In addition, mobility measurements were significantly greater for experimental titanium-alloy implants during the first 3 months (P < .05). Clinical attachment level measurements were most sensitive to peri-implant status. All implants were equally susceptible to ligature-induced peri-implant breakdown. Consequently, meticulous oral hygiene and regular maintenance care are prerequisites for successful implantology.

Issues related to single-tooth implants.

Many practitioners place single-tooth implants when the teeth adjacent to the edentulous space are intact, free of caries and have had no restorations, and the patient is reluctant to wear a removable appliance for physical or psychological reasons, or both. The main exclusionary factors for a single-tooth dental implant are insufficient bone quantity, poor bone quality and insufficient vertical interarch space to accommodate the prosthodontic components of the implant.

Regeneration of dehisced alveolar bone adjacent to endosseous dental implants utilizing a resorbable collagen membrane: clinical and histologic results.

The purpose of this study was to evaluate the usefulness of resorbable collagen membrane for guided tissue regeneration. Dehiscences were surgically induced in dog mandibles. Hydroxyapatite-coated or grit-blasted implants were then placed in a random pattern in both sides of the mandibles (two of each type of implant in each side of the mandible). A resorbable collagen barrier membrane was placed around one pair of implants on each side. The other two implants on each side served as controls. The sites were examined clinically and histologically after 4 or 8 weeks to assess bone regeneration. Sites around experimental hydroxyapatite-coated and grit-blasted implants showed significantly more bone fill than did control sites. In addition to its apparent ability to encourage bone regeneration, the collagen membrane is resorbable, obviating the need for a second surgery to allow removal. (Int J Periodont Rest Dent 1993; 13:71-83.)

Clinical evaluation of anorganic bovine bone xenograft with a bioabsorbable collagen barrier in the treatment of molar furcation defects.

The purpose of this study was to compare Bio-Oss (BO), an anorganic bovine bone xenograft, in combination with Bio-Gide (BG), a bioabsorbable collagen barrier, to open-flap debridement (OFD) surgery in human mandibular Class II furcation defects. A total of 31 furcations (18 treatment, 13 control) in 21 patients were treated. There was a statistically significant improvement in most clinical indices for the BO/BG group, with minimal improvement noted for the OFD group. Vertical probing depth reduction of 2.0 mm and horizontal probing depth reduction of 2.2 mm were noted for the BO/BG group, with 0.3 mm and 0.2 mm reductions, respectively, noted for OFD. Hard tissue measurements showed 2.0 mm of vertical furcation bone fill for BO/BG and 0.5 mm for OFD. The BO/BG group had 3.0 mm of horizontal furcation bone fill, and the OFD group had 0.9 mm. The BO/BG group had a defect resolution of 82.7%; 42.5% was noted for the OFD group. There was a statistically significant difference between BO/BG and OFD in all soft and hard tissue measurements with the exception of attachment level, recession, and alveolar crest resorption.

Clinical management of failing dental implants: four case reports.

Two-stage, endosseous dental implants have become a clinically acceptable treatment modality for the restoration of function and esthetics in edentulous areas. One system (Biotes, Nobel-pharma) currently has full approval from the ADA for use in full edentulous cases, while several other systems have provisional approval. Several professional journals and lay magazines have published information about implants, and this has stimulated interest on the part of both the dentist and the patient. Many different brands of implant systems are now available for the clinician to utilize, and the manufacturers of these implants have established training programs designed to teach both the generalist and the specialist the correct placement and restoration of their particular implants. With an increase in the number of implants being placed, it is inevitable that the number of complications will likewise rise. While current implant literature is replete with information concerning the concept of osseointegration, success rates, and examples of restorative techniques, there is very little information available on guidelines for patient evaluation and selection, clinical maintenance homecare, or treatment considerations for system failure. It is conceivable that an implant that was correctly placed and exhibited all the criteria for success at the time of surgical exposure may develop problems subsequent to restoration. Since the investment for the patient is significant in terms of time, finances, and trust in the practitioner(s), the periodontist may be called upon to intervene in such cases to improve the prognosis. The purpose of this paper is to present four case reports that illustrate several treatment modalities for the clinical management of implant problems that developed at the time of, or following, exposure.

Histologic evaluation of the LaminOss osteocompressive dental screw: a pilot study.

This animal study compared the response of canine mandibular bone using the orthopedic principle of osteocompression by the function of an immediately loaded dental implant vs an unloaded dental implant of the same design and size. Two dogs were partially edentulated in the mandible. A total of 8 osteocompressive screw implants, 2 per quadrant were placed and evaluated histomorphometrically after 3 days in 1 dog and after 3 months in the second dog. The second dog had a two-unit fixed bridge placed immediately postsurgically in occlusal function on the right side; on the left side, the implants were splinted out of occlusion as a control. Histologically, no bone necrosis was observed at the implant interface by any of the 8 implants for either period as a direct result of the 4-mm-diameter by 13-mm-length implant design. Clinical parameters did not differ among the implants; however, at 3 months, the immediately loaded implants demonstrated more than twice the amount of bone density at their surfaces compared to the unloaded implants of the same design. Future human clinical research would be necessary to provide a meaningful statistical analysis to validate the importance of this implant design and the function of osteocompression.

Implant maintenance using a modified ultrasonic instrument.

With the increasing number of implants in place, oral hygiene and maintenance are imperative because implants are susceptible to plaque accumulation and calculus formation. This case study evaluated a modification of the common ultrasonic tip to remove calcified deposits on implant abutments and prostheses, and also evaluated ultrastructural changes on polished titanium. A modified "plastic" ultrasonic instrument was found to be clinically effective and efficient. This instrument, unlike a metal ultrasonic tip on an ultrastructural level, produced no irreversible changes on the evaluated commercially pure titanium test strip. The preliminary results of this modification of an ultrasonic instrument show promise for its use as an implant maintenance modality.

Periodontitis and periimplantitis: one and the same?

Research shows that the same anaerobic, gram-negative pathogens are present in the periodontal and implant pocket or crevice. The implants in a partially edentulous case are probably more at risk due to the bacteria being more pathogenic and a seeding mechanism from the tooth pocket to the implant crevice. In the face of a normal microbial flora, retrograde periimplantitis or radiographic bone loss without gingival changes may be due to trauma because of overloading, loading too soon, and/or loading in a lateral direction. Finally, the combination of an infective process (periimplantitis) and noninfective or traumatic process (retrograde periimplantitis) will result in rapid osseous destruction and, possibly, loss of the implant fixture(s).

Guided tissue regeneration around dental implants: three case reports.

This article demonstrates the use of guided tissue regeneration (GTR) principles for regeneration of bone tissue in jaw bone defects associated with dental implant placement. The learning objective of this article is the technique of bone tissue regeneration using the barrier membranes. Three cases are presented to illustrate the procedure. In all of them, the barrier membrane was used to cover the surgical site after the placement of dental implants and bone grafts.