Staged Sinus Floor Elevation Using Novel Low-Crystalline Carbonate Apatite Granules: Prospective Results after 3-Year Functional Loading

Guided Bone Regeneration Using Carbonated Apatite Granules and L-Lactic Acid/ε-Caprolactone Membranes: A Case Series and Histological Evaluation

Background/Objectives: The newly developed poly L-lactic acid/ε-caprolactone (P(LA/LC)) membrane has recently been proposed as a guided bone regeneration (GBR) procedure in implant treatment. This case series details the clinical, radiographic, and histological results of ridge augmentation using bone graft comprising a P(LA/LC) membrane and carbonated apatite for implant treatment. Methods: Ten patients (15 sites) requiring bone augmentation and implant placement were retrospectively assessed. Simultaneous implant placement (Si) was performed at five sites in three patients. Si immediately following tooth extraction (SiIP) was performed at four sites in four patients. The staged approach (St) was performed at six sites in three patients. In the St-treated cases, hard tissue samples were taken from the implant placement site under patient consent. Results: The mean regenerated bone width for each treatment method was Si, 6.34 ± 2.64 mm (excluding implant diameter, 2.60 ± 2.42); SiIP, 7.55 ± 1.17 mm (excluding implant diameter, 3.90 ± 0.78) and St, 5.57 ± 1.08 mm. The mean regenerated bone width for all the cases was 6.36 ± 1.83 mm (excluding implant diameter, 4.14 ± 1.99). Significant differences were observed between the pre- and post-operative bone width in all the cases and the SiIP group (p < 0.001). All cases were followed up for more than 2 years after attaching the superstructure. No inflammation, shrinkage, or other problems were observed in the hard and soft tissues surrounding the implant. In the histological evaluation, there was no soft tissue ingrowth into the augmented bone, and new bone formation was observed. Conclusions: The use of P(LA/LC) membranes and carbonated apatite as GBR materials in implant treatment resulted in stable and favorable bone augmentation.

A Case of Simultaneous Sinus Augmentation and Oroantral Fistula Closure for Implant Preparation

An oroantral communication may form in the upper molar region after tooth extraction. The patient is a 59-year-old female, who is a nonsmoker. At the initial visit, teeth #14, #15, and #17 were missing. After tooth #16 was extracted due to apical periodontitis, a bone defect with a diameter of approximately 4 mm was observed, leading to the formation of an oroantral fistula (OAF). Another window was created in the lateral wall adjacent to the superior part of the bone defect at the fistula site to achieve closure of the OAF through bone formation and simultaneously perform sinus floor elevation (lateral approach) for implant placement. Through this lateral window, instruments were inserted into the maxillary sinus towards the bone defect at the fistula site. During this process, the remaining bone between the lateral window and the bone defect at the fistula site was carefully removed with instruments, connecting the two bone defects to facilitate manipulation of the instruments. The Schneiderian membrane was elevated without enlarging the tear. Six months after these surgeries, a cone beam computerized tomography (CBCT) scan confirmed the closure of the fistula with hard tissue and the elevation of the sinus floor. Subsequently, three implants were placed, and prosthetic treatment was completed. Follow-up data is provided, including periapical X-ray and CBCT images taken 2 years and 3 months after surgery (1 year and 3 months after the placement of the final prosthetic structure). The progress so far has been favorable.

Preclinical Evaluation of a Poly (Lactic Acid/Caprolactone) Bilayer Membrane and a Carbonate Apatite for Periodontal Regeneration: A Canine One-Wall Intrabony Defect Model

AIMS

This preclinical study aimed to evaluate the periodontal tissue regenerative capacities of poly (lactic acid/caprolactone) (PLCL) bilayer membrane in one-wall intrabony defects in dogs. No study has assessed the efficacy of PLCL bilayer membrane for periodontal regeneration therapy despite the fact that PLCL bilayer membrane has proved efficient for bone regeneration.

METHODS

In five beagle dogs, the bilateral mandibular second and fourth premolars were extracted 8 weeks before the experimental surgery. Standardized bone defects (5 mm in height and 6 mm in width) were surgically created on the mesial and distal roots of the bilateral third premolars in the mandible. The test groups were set up as follows: (i) carbonate apatite (CO3Ap) + PLCL, (ii) CO3Ap, (iii) xenograft (DBBM) + collagen membrane (CM), and (iv) DBBM. The control group was left empty. Radiological, histologic and histomorphometric characteristics were compared 8 weeks after surgery.

RESULTS

No infectious complications were detected at any of the tested sites. The test groups exhibited a greater height and volume of the newly formed bone than the control group. They also showed a greater height of the newly formed cementum than the control group. However, the results were not statistically significant. The newly formed periodontal ligaments were inserted into newly formed bone and cementum in the test groups.

CONCLUSION

The combined use of PLCL bilayer membrane and CO3Ap demonstrated comparable performance for periodontal tissue regeneration in one-wall intrabony defects compared to conventional therapies.

A systematic review of a novel alloplast carbonate apatite granules

The objectives of this study are to provide a systematic review of a novel alloplastic hard-tissue grafting material, carbonate apatite granules (CO3Ap-granules), to provide a clinical case presentation of CO3Ap-granules in periodontal surgery. The following three electronic databases were searched independently by two of the authors (MN) and (CR): National Library of Medicine [MEDLINE (PubMed) and ClinicalTrials.gov], EMBASE (OVID) and the Cochrane Central Register of Controlled Trials (CENTRAL). After searching electronic databases, select journals in periodontics and implantology were also manually searched. Of the 43 studies identified from the systematic review, the following classifications were determined: (1) in vitro studies - 5 studies, (2) animal studies - 28 studies, (3) clinical studies - 7 studies, (4) reviews - 3 studies. Results from selected animal studies and all human studies were summarized. These results demonstrate that the novel alloplast CO3Ap-granules has the potential ability to stimulate new bone formation while CO3Ap-granules simultaneously resorb over time. Replacement of CO3Ap-granules with new bone formation has been shown to be comparable to autogenous bone grafting with one study showing superior results to a bovine-derived xenograft.

Ridge Preservation and Augmentation Using a Carbonated Apatite Bone Graft Substitute: A Case Series

The newly developed mineral carbonated apatite has recently been proposed as a bone graft material for bone regenerative treatment in implant therapy. This case series details the clinical and radiographic outcomes of ridge preservation and ridge augmentation using only carbonated apatite as bone graft material for implant treatment. Twenty patients (36 sites) who required bone regeneration and implant placement were retrospectively assessed. Simultaneous carbonated apatite implant placement was performed using the simultaneous ridge preservation or augmentation approach on 24 sites in 13 patients with sufficient bone quantity for primary stabilization based on preoperative evaluation results. A staged ridge preservation or augmentation approach was used for the remaining 12 sites in seven patients with insufficient bone quantity. The mean regenerated bone height for each treatment method was as follows: simultaneous preservation, 7.4 ± 3.3 mm; simultaneous augmentation, 3.6 ± 2.3 mm; staged preservation, 7.2 ± 4.5 mm; and staged augmentation, 6.1 ± 2.7 mm. The mean regenerated bone width for each treatment method was as follows: simultaneous preservation, 6.5 ± 2.9 mm; simultaneous augmentation, 3.3 ± 2.5 mm; staged preservation, 5.5 ± 1.7 mm; and staged augmentation, 3.5 ± 1.9 mm. Ultimately, the use of carbonated apatite alone as a bone graft material in implant therapy resulted in stable and favorable bone regeneration.

Bone-Regeneration Therapy Using Biodegradable Scaffolds: Calcium Phosphate Bioceramics and Biodegradable Polymers

Calcium phosphate-based synthetic bone is broadly used for the clinical treatment of bone defects caused by trauma and bone tumors. Synthetic bone is easy to use; however, its effects depend on the size and location of the bone defect. Many alternative treatment options are available, such as joint arthroplasty, autologous bone grafting, and allogeneic bone grafting. Although various biodegradable polymers are also being developed as synthetic bone material in scaffolds for regenerative medicine, the clinical application of commercial synthetic bone products with comparable performance to that of calcium phosphate bioceramics have yet to be realized. This review discusses the status quo of bone-regeneration therapy using artificial bone composed of calcium phosphate bioceramics such as β-tricalcium phosphate (βTCP), carbonate apatite, and hydroxyapatite (HA), in addition to the recent use of calcium phosphate bioceramics, biodegradable polymers, and their composites. New research has introduced potential materials such as octacalcium phosphate (OCP), biologically derived polymers, and synthetic biodegradable polymers. The performance of artificial bone is intricately related to conditions such as the intrinsic material, degradability, composite materials, manufacturing method, structure, and signaling molecules such as growth factors and cells. The development of new scaffold materials may offer more efficient bone regeneration.

Volume change after maxillary sinus floor elevation with apatite carbonate and octacalcium phosphate

PURPOSE

Maxillary molars have low alveolar bone height diameter due to the presence of the maxillary sinus; thus, a sinus lift may be required in some cases. Changes in the volume of bone substitutes can affect the success of implant therapy. Therefore, this study aimed to compare the changes in the volume of two different bone substitutes-one based on carbonate apatite and the other on octacalcium phosphate-used in maxillary sinus floor elevation.

METHODS

Nineteen patients and 20 sites requiring maxillary sinus floor elevation were included in the study. Digital Imaging and Communications in Medicine data for each patient obtained preoperatively and immediately and 6 months postoperatively were used to measure the volume of the bone grafting material using a three-dimensional image analysis software. The immediate postoperative volume of octacalcium phosphate was 95.3775 mm3 per piece of grafting material used. It was multiplied by the number of pieces used and converted to mL to determine the immediate postoperative volume.

RESULTS

The mean resorption values of carbonate apatite and octacalcium phosphate were 12.7 ± 3.6% and 17.3 ± 3.9%, respectively. A significant difference in the amount of resorption of the two bone replacement materials was observed (P = 0.04).

CONCLUSIONS

The results of this study indicate that both bone substitute materials tend to resorb. The two bone grafting materials that are currently medically approved in Japan have not been in the market for a long time, and their long-term prognosis has not yet been reported. Further clinical data are warranted.

Comparison of Orthodontic Tooth Movement of Regenerated Bone Induced by Carbonated Hydroxyapatite or Deproteinized Bovine Bone Mineral in Beagle Dogs

Orthodontic treatments often involve tooth movement to improve dental alignment. In this study, we aimed to compare tooth movement in regenerated bone induced by two different bone fillers, carbonated hydroxyapatite (CAP) and deproteinized bovine bone mineral (DBBM). Four beagle dogs were used in this comparative study. The first, second, and fourth lower mandibular premolars (P1, P2, and P4) on both sides of the mouth were extracted, and CAP was implanted into the extraction site on the left side and DBBM into the right side. Following regenerative bone healing, orthodontic devices were attached to perform orthodontic tooth movement of the lower third mandibular premolar (P3) on both sides. X-ray examination, intraoral scan, and histological analysis were performed. The Mann-Whitney U test was used for statistical analysis, and p < 0.05 was considered significant. Bone regeneration and orthodontic tooth movement were observed in the CAP and DBBM groups. Histologically, normal periodontal tissue remodeling was observed on the compression and tension sides of CAP and DBBM. No statistical difference was observed in the number of osteoclasts around the periodontal ligament and the root resorption area. Orthodontic tooth movement of regenerated bone induced by CAP and DBBM was therefore achieved.

Evaluation of Eruption of Permanent Teeth in Beagle Dog Extraction Sites Filled with Carbonate Apatite

Autologous bone grafting is the primary method for treating alveolar clefts. However, bone grafting materials are desired as alternatives to autogenous bone to reduce surgical invasiveness. Here, we present an animal study evaluating the effect of carbonate apatite (CA) on the spontaneous eruption of permanent teeth. The bone grafting materials included CA, natural bovine bone (BB), and hydroxyapatite (HA). In 15 8-week-old male beagle dogs, the left mandibular deciduous premolars (DP) two and three were extracted and subsequently filled with CA, BB, and HA. The animals were euthanized after a predetermined number of days, and samples were collected for microcomputed tomography and histological evaluation. Spontaneous eruption of the succeeding permanent teeth (P3 and P4) was observed in the CA group at 14 weeks. Delayed eruption of the succeeding permanent teeth was observed in the BB and HA groups. CA could serve as a viable alternative to autogenous bone for treating alveolar clefts.

Reconstruction of rabbit mandibular bone defects using carbonate apatite honeycomb blocks with an interconnected porous structure

Carbonate apatite (CO₃Ap) granules are useful as a bone substitute because they can be remodeled to new natural bone in a manner that conforms to the bone remodeling process. However, reconstructing large bone defects using CO₃Ap granules is difficult because of their granular shape. Therefore, we fabricated CO₃Ap honeycomb blocks (HCBs) with continuous unidirectional pores. We aimed to elucidate the tissue response and availability of CO₃Ap HCBs in the reconstruction of rabbit mandibular bone defects after marginal mandibulectomy. The percentages of the remaining CO₃Ap area and calcified bone area (newly formed bone) were estimated from the histological images. CO₃Ap area was 49.1 ± 4.9%, 30.3 ± 3.5%, and 25.5 ± 8.8%, whereas newly formed bone area was 3.0 ± 0.6%, 24.3 ± 3.3%, and 34.7 ± 4.8% at 4, 8, and 12 weeks, respectively, after implantation. Thus, CO₃Ap HCBs were gradually resorbed and replaced by new bone. The newly formed bone penetrated most of the pores in the CO₃Ap HCBs at 12 weeks after implantation. By contrast, the granulation tissue scarcely invaded the CO₃Ap HCBs. Some osteoclasts invaded the wall of CO₃Ap HCBs, making resorption pits. Furthermore, many osteoblasts were found on the newly formed bone, indicating ongoing bone remodeling. Blood vessels were also formed inside most of the pores in the CO₃Ap HCBs. These findings suggest that CO₃Ap HCBs have good osteoconductivity and can be used for the reconstruction of large mandibular bone defects. The CO₃Ap HCB were gradually resorbed and replaced by newly formed bone.

Preparation of Collagen/Hydroxyapatite Composites Using the Alternate Immersion Method and Evaluation of the Cranial Bone-Forming Capability of Composites Complexed with Acidic Gelatin and b-FGF

Bone-substitute materials are essential in dental implantology. We prepared collagen (Col)/hydroxyapatite (Hap)/acidic gelatin (AG)/basic fibroblast growth factor (b-FGF) constructs with enhanced bone-forming capability. The Col/Hap apatite composites were prepared by immersing Col sponges alternately in calcium and phosphate ion solutions five times, for 20 and 60 min, respectively. Then, the sponges were heated to 56 °C for 48 h. Scanning electron microscopy/energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analyses showed that the Col/Hap composites contained poorly crystalline Hap precipitates on the Col matrix. Col/Hap composite granules were infiltrated by AG, freeze-dried, and immersed in b-FGF solution. The wet quaternary constructs were implanted in rat cranial bone defects for 8 weeks, followed by soft X-ray measurements and histological analysis. Animal studies have shown that the constructs moderately increase bone formation in cranial bone defects. We found that an alternate immersion time of 20 min led to the greatest bone formation (p < 0.05). Constructs placed inside defects slightly extend the preexisting bone from the defect edges and lead to the formation of small island-like bones inside the defect, followed by disappearance of the constructs. The combined use of Col, Hap, AG, and b-FGF might bring about novel bone-forming biomaterials.

Surgical Periodontal Therapy Using Recombinant Human Fibroblast Growth Factor-2 in Combination with Carbonate Apatite Granules for Stage III Grade B Periodontitis: A Case Report with 1-year Follow-up

This report describes a case of generalized chronic periodontitis requiring periodontal treatment including regenerative therapy. The patient was a 60-year-old woman who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of tooth mobility and pain in tooth #26. Periodontal examination at the first visit revealed that 32.0% of sites had a probing depth of ≥4 mm and 43.8% bleeding on probing. Radiographic examination revealed vertical bone resorption in #17. Horizontal resorption was noted in other areas. Initial periodontal therapy consisting of plaque control, scaling and root planing, and caries treatment was performed based on a clinical diagnosis of Stage III Grade B periodontitis. Tooth #26 was extracted due to bone resorption extending as far as the root apex. After reevaluation, periodontal regenerative therapy using recombinant human fibroblast growth factor-2 (rhFGF-2) in combination with carbonate apatite (CO₃Ap) granules was performed for #17. Following reevaluation, a zirconia crown (#16) and zirconia bridge (#24-27) were placed. Following further reevaluation, the patient was placed on supportive periodontal therapy (SPT). The periodontal regenerative therapy using rhFGF-2 with CO₃Ap granules yielded an improvement in the vertical bone resorption observed in #17. This improvement has been adequately maintained over a 1-year period postoperatively. Continued SPT is needed to maintain stable periodontal conditions.

Primary stability of different implant macrodesigns in a sinus floor elevation simulated model: an ex vivo study

BACKGROUND

A novel type of implant (Straumann® BLX implant) has been developed for certain stability from the mechanical and biological aspects and is expected for the implant placement in atrophic maxilla with sinus floor elevation (SFE).

PURPOSE

The aim of this study was to evaluate the primary stability in the implants with different macrodesigns in an SFE simulated model. Primary stabilities defined as maximum insertion torque (MIT) and implant stability quotient (ISQ) were compared between this novel type of implant and other types.

MATERIALS AND METHODS

Five types of Straumann® 10 mm length implants (Standard Plus; SP, Tapered Effect; TE, Bone Level; BL, Bone Level Tapered; BLT and BLX) and two types of Straumann® 6 mm length implants (SP short, BLX short) were used in this study. Each implant was inserted through 5 mm-thick porcine iliac crest blocks (an SFE simulated model). Primary stability was evaluated by using MIT and ISQ.

RESULTS

The mean value of MIT for BLX group showed significantly higher values than SP, BL (p < 0.01), and TE (p < 0.05) groups. The mean value of ISQ for BLX group was significantly higher than the other groups (p < 0.01). The mean value of MIT and ISQ for BLX and BLX short group were significantly higher than those for SP and SP short group (p < 0.01).

CONCLUSIONS

In an SFE simulated ex vivo model, BLX group showed the highest values. These results suggest that implant selection can play a crucial role in the achievement of primary stability during SFE and simultaneous implant placement.

Combination of Carbonate Hydroxyapatite and Stem Cells from Human Deciduous Teeth Promotes Bone Regeneration by Enhancing BMP-2, VEGF and CD31 Expression in Immunodeficient Mice

The objective of this study was to clarify the efficiency of a combination of stem cells from human deciduous teeth and carbonate apatite in bone regeneration of calvarial defects. Immunodeficient mice (n = 5 for each group/4 groups) with artificial calvarial bone defects (5 mm in diameter) were developed, and stem cells from human deciduous teeth (SHEDs) and carbonate hydroxyapatite (CAP) granules were transplanted with an atelocollagen sponge as a scaffold. A 3D analysis using microcomputed tomography, and 12 weeks after transplantation, histological and immunohistochemical evaluations of markers of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and cluster of differentiation (CD) 31 were performed. In the 3D analysis, regenerated bone formation was observed in SHEDs and CAP, with the combination of SHEDs and CAP showing significantly greater bone regeneration than that in the other groups. Histological and immunohistochemical evaluations showed that combining SHEDs and CAP enhanced the expression of BMP-2, VEGF, and CD31, and promoted bone regeneration. This study demonstrates that the combination of SHEDs and CAP transplantation may be a promising tool for bone regeneration in alveolar defects.