A clinical evaluation of hydroxyapatite cement in the treatment of Class III furcation defects

BACKGROUND

Calcium hydroxyapatite cement (HAC) has been demonstrated in both animal models and human craniofacial defects to be safe, absorbable, osteoconductive, and possibly osteoinductive. This pilot study evaluated a novel technique using HAC to surgically obturate Class III mandibular molar furcation defects.

METHODS

Following flap reflection, affected teeth in 6 patients were root planed and etched with citric acid. Experimental sites were grafted with HAC and coronally positioned flaps (CPF), while controls were treated by CPF only. A variety of clinical parameters were recorded initially, and at re-entry surgery 9 months later.

RESULTS

At re-entry, all experimental sites exhibited granulation tissue interposed between the HAC and the alveolar bone, and clinical findings were unsatisfactory. Mean probing depth, clinical attachment loss, and recession increased by 0.8 mm, 1.9 mm, and 1.2 mm, respectively, in experimental sites. In controls, mean probing depth decreased by 0.8 mm, and clinical attachment loss and recession increased by 0.3 mm and 1.2 mm, respectively. There was a mean 1.6 mm loss in osseous crest height and a mean 2.2 mm worsening in osseous defect depth for experimental sites, but only a 0.5 mm loss in osseous crest and 0.5 mm increase in osseous defect depth in control sites.

CONCLUSIONS

Experimental sites lost 1.0 to 1.5 mm in bone and attachment compared to controls, without any significant clinical benefit. While the concept of surgically obturating Class III furcation defects with a safe, osteoconductive material remains attractive, HAC did not promote repair or regeneration in this technique.

Comparison of bioabsorbable laminar bone membrane and non-resorbable ePTFE membrane in mandibular furcations

The purpose of the study was to compare clinical parameter changes and osseous regeneration in 12 pairs of comparable Class II mandibular molar furcation invasion defects using either a bioabsorbable demineralized laminar bone allograft membrane or a non-resorbable expanded polytetrafluoroethylene (ePTFE) membrane as a barrier in guided tissue regeneration. Measurements with calibrated periodontal probes were made to determine soft tissue recession, probing depth, and attachment levels. Defects within each pair were randomly selected for treatment with either bioabsorbable demineralized bone allograft membrane or ePTFE membrane. All defects were concurrently grafted with particulate demineralized freeze-dried bone allograft (DFDBA). Additional measurements were made at surgery to determine crestal resorption and the vertical and horizontal dimensions of the osseous defects. The temporal course and extent of membrane exposures were also recorded. The non-resorbable membrane was retrieved 6 weeks following placement. Six months following initial surgical treatment, each site was surgically re-entered and all soft and hard tissue measurements repeated. Descriptive statistical analysis revealed that both treatments resulted in significant within-group mean vertical and horizontal osseous fill, but no statistical difference emerged between the groups. As based on this pilot study, laminar bone membrane may be as effective as ePTFE when used in conjunction with DFDBA for treatment of Class II mandibular molar furcation bone defects. This pilot study of low power suggests that these two materials may be equivalent when used in conjunction with DFDBA. Further studies of much higher power and of the laminar bone alone as compared to positive and negative controls are required. Laminar bone does not require a secondary surgical procedure for removal and may undergo less frequent instances and degrees of exposure during healing.

Occlusal trauma: a case in perspective

The decision to initiate occlusal therapy as part of periodontal treatment is often controversial. This case report illustrates an indication for providing such therapy and suggests an appropriate sequence to follow for achieving a desirable outcome.

Clinical evaluation of guided tissue regeneration in the treatment of grade II molar furcation invasions

This paper evaluates the use of guided tissue regeneration for treating 19 pairs of molar grade II furcation defects. Presurgical measurements were taken for the determination of aveolar crestal resorption, vertical open probing attachment, and horizontal open probing attachment. The surgical procedure consisted of sulcular incision, full-thickness facial and lingual flaps, soft tissue debridement, and root planing. One defect from each pair of furcas was treated with an expanded polytetrafluoroethylene membrane, which was left in place for 4 to 6 weeks. Postsurgery soft tissue measurements showed a reduction in probing depth and a gain in vertical and horizontal open probing attachment.

The osteogenic potential of two composite graft systems using osteogenin

The purpose of this study was to determine the quantity of new bone formation in critical sized calvaria defects in rats treated with two composite graft systems. The systems consisted of either a combination of the bone inductive protein (osteogenin) plus type I collagen (Os + C) or the combination of osteogenin with coralline hydroxyapatite (Os + HA). Additional treatments consisted of coralline hydroxyapatite (HA) or untreated control defects. After 28 days the calvaria were recovered and processed for quantitative radiography (radiomorphometry) and histomorphometry. Histomorphometric results were based on quantitation of regenerated trabecular bone. Results indicated that the Os + C combination produced substantially more bone than the Os + HA, HA, or control groups (P less than 0.05). Radiomorphometric assessment was based on the detection of radiopacity in the calvarial wounds. Due to the radiopaque property of HA, it was not possible to accurately quantitate the radiopacity of the regenerating bone from HA and host bone. Therefore, conclusions about the efficacy of the treatments must be derived from histomorphometric data. Results from histometric measurements of healing indicate that the Os + C combination has the greatest potential for regenerating calvarial bone defects. The potential for osteogenin in regenerating alveolar bone lost due to periodontal disease is suggested by these studies.

A comparison of freeze-dried bone allograft and demineralized freeze-dried bone allograft in human periodontal osseous defects

This study was conducted to clinically compare freeze-dried bone allograft (FDBA) and demineralized freeze-dried bone allograft (DFDBA). Twenty-two defects (11 intrapatient pairs) in 9 patients were grafted with either DFDBA or FDBA. Evaluations were based on standardized radiographs, presurgical and postsurgical soft tissue measurements using the cemento-enamel junction as a fixed reference point, and osseous measurements at the time of surgery. Grafted sites were re-entered at a minimum of 6 months following placement. A mean osseous repair of 1.7 mm (59%) occurred with DFDBA and 2.4 mm (66%) with FDBA. A mean clinical attachment gain of 1.7 mm was obtained with DFDBA and 2.0 mm with FDBA. Probing depths decreased a mean of 2.00 mm with both DFDBA and FDBA. These findings reveal no significant differences between the two materials in primarily intraosseous defects when evaluated at a minimum 6 months postsurgery.

Comparison of freeze-dried bone allograft and porous hydroxylapatite in human periodontal defects

This study was conducted to clinically compare the efficacy of freeze-dried bone allograft (FDBA) and porous hydroxylapatite granules. Nineteen pairs of intraosseous defects were grafted in seven patients. One defect of each pair was implanted with FDBA, the other with granular porous hydroxylapatite. Matching defects were treated similarly in all other aspects. Evaluations were based on both preoperative and postoperative measurements from a fixed reference point, standardized radiographs, surgical osseous measurements, and histology of degranulated tissues. Grafted sites were reentered 6 to 11 months postsurgery. Results showed a mean osseous fill of 2.1 mm for FDBA versus 1.3 mm for granular porous hydroxylapatite (P = .07). A mean clinical attachment gain of 2.2 mm for FDBA versus 1.3 mm for granular porous hydroxylapatite (P less than .05), and a mean decrease in probing depths of 3.0 mm for FDBA versus 1.4 mm for granular porous hydroxylapatite (P less than 0.5) was found. FDBA was clinically indistinguishable from host bone, whereas porous hydroxylapatite appeared to be separated from host bone by soft tissue. The data and clinical findings suggested that FDBA may have some enhanced reparative potential when compared to granular porous hydroxylapatite in the treatment of periodontal defects in humans.

Histologic evaluation of bone inductive proteins complexed with coralline hydroxylapatite in an extraskeletal site of the rat

The purpose of this histologic and biochemical study was to assess the osteogenic potential of bone inductive proteins complexed with coralline hydroxylapatite as the carrier vehicle after implantation in an extraskeletal site of the rat. Inductive proteins were extracted from bovine demineralized bone. Implants were placed in 16 male, 3-month old Long-Evans rats (200-300 grams), using paired subcutaneous sites overlying the ventral thorax. There were four experimental groups, with eight implants per group. These included hydroxylapatite alone (HA), hydroxylapatite with inductive protein (HA + P), inactive demineralized bone matrix with (IBM + P), and without inductive protein (IBM). All implants were harvested at 21 days. Findings indicate a lack of osteogenic potential in groups HA, HA + P, and IBM. However, when HA and HA + P were compared, there was a 79% increase in standardized field mean nuclear point counts in the HA + P group. Also, compared to the other three implant groups, controls of IBM + P histomorphometrically showed chondroid bone formation and increased alkaline phosphatase activity. In this model system it may be concluded that with a composite system of coralline hydroxylapatite and bovine-derived inductive protein, bone formation was not seen; positive controls consisting of IBM + P demonstrated a statistically significant increase in AP activity with corresponding histologic evidence of bone formation.

The osteogenic potential of two human demineralized bone preparations using a xenogeneic model

The relative osteogenic potential of two different preparations of lyophilized human demineralized bone were evaluated using a heterotopic site in a rodent model. Human diaphyseal cortical bone (75-850 microns) was demineralized according to two different protocols for decalcified bone allograft (A.H. Reddi and M.R. Urist). Equal volumes of mineralized lyophilized human bone and a proprietary hydroxylapatite served as controls. Thirty-two Long-Evans rats divided into four groups received subcutaneous implants of one of these four preparations. Implants were harvested at two, four, and six weeks. Histometric analysis of limited serial sections at six weeks demonstrated new bone formation by the two demineralized preparations only. The Reddi protocol produced significantly more bone formation (1.13 +/- 1.21%) than the Urist preparation (0.53 +/- 0.31%). Although bone induction by both the Reddi and Urist protocol was sparse within this xenogeneic system, the Reddi preparation may offer some slight advantage of greater osteogenic potential and ease of preparation. The low yields of induced bone in response to implants of human demineralized bone would limit the use of this model system in assessing osteogenic potential prior to clinical use.