INTRODUCTION
The paradigm shifts to the concept of prosthetically driven implant placement and esthetics have resulted in increased need of regenerative procedures. Changes in the alveolar ridge profile as a consequence of extraction of teeth, trauma, or periodontal disease may preclude dental implant placement due to insufficient bone. However, advancement in biomaterials and bone augmentation techniques have widened the scope of implant rehabilitation. Studies have shown that lateral bone augmentation procedures are highly predictable, with high implant survival rates of 99%–100% for staged approaches.[ 1 ]
Among the various bone grafting materials available for augmentation, synthetic carbonate apatite, which has composition similar to that of native autogenous bone, has gained clinical attention.[ 2 ] Carbonate apatite has shown higher bone-forming ability by virtue of osteoconduction property.[ 3 ] To obtain biomimetic effect, carbonate apatite has been combined with collagen. Studies have shown that this combination results in unique structural and mechanical properties that enhance space maintaining ability and show higher bone-forming potential in bone defects.[ 4 , 5 ] The present study consists of a case report aimed at investigating the effect of composite bone graft (CBG) with ribose cross-linked collagen membrane (RCLM) in lateral augmentation of alveolar ridge that is planned for dental implant placement.
CASE REPORT
A 42-year-old nonsmoker male patient visited our outpatient department with a missing left central incisor (tooth #9) in September 2021. Tooth #9 was extracted 12 months before due to mobility of tooth caused due to trauma. Upon clinical and radiological examination, the patient was diagnosed with localized periodontitis, Stage II, Grade A. Based on the Straightforward, Advanced, and Complex classification, the ridge defect was found to be complex because of horizontal deficiency requiring before grafting.
Treatment plan consisted of oral hygiene instruction and scaling and root planning. After evaluation of the buccal bone defect using cone-beam computed tomography (CBCT) scan, Guided bone regeneration(GBR) using CBG and RCLM was planned as the therapeutic option for site of #9. Horizontal ridge dimension at crest was 3.4 mm and 7 mm and 8.5 mm at 3 and 6 mm levels, respectively [Figure 1a ].A written informed and signed consent form was obtained before the treatment.
Figure 1: (a) Preoperative cone-beam computed tomography scan; (b) postoperative cone-beam computed tomography scan
Preprocedural rinse with chlorhexidine gluconate 0.2% mouthwash (Clohex ADS® mouthwash) was asked to done by the subject. Local anesthesia was obtained with buccal and palatal infiltrations using 2% lignocaine and 1:80,000 epinephrine. Midcrestal incision was made using #15 blade and full-thickness mucoperiosteal flap was raised buccally. To obtain tension-free adaptation of flap margins, the buccal flap advancement was done using periosteal releasing incision. After reflection of flap, thorough debridement of the region was performed to avoid any soft tissue remnants. Decortication was performed to ensure better vascularization. CBG (RegenerOss® Synthetic, ZimVie) is a calcium phosphate-based mineral with a carbonate apatite structure similar to natural bone combined with type I collagen derived from bovine Achilles tendon. It was soaked in saline for hydration and molded on to the bone defect. RCLM membrane (Ossix Volumax® , Datum Dental, Palm Beach, USA) was used to cover the grafted area. Stabilization was achieved using periosteal suturing method for the membrane and two-layered suturing technique to achieve tension-free flap closure at the wound margin with Vicryl 4.0, 3/8, reverse cutting resorbable sutures (Ethicon, Hamburg, Germany) [Figure 2 ].The patient was advised to refrain from brushing the area until 15 days and chlorhexidine gluconate 0.2% mouthwash (Clohex ADS® mouthwash) was prescribed to use twice a day for 4 weeks. The patient was given amoxicillin 500 mg to be taken three times a day for 5 days and ibuprofen 600 mg to be taken every 4–6 h as needed.
Figure 2: Steps in lateral bone augmentation. (a) Preoperative bone defect; (b) preoperative lateral bone width visualized clinically; (c) mucoperiosteal flap reflection and visualization of residual alveolar ridge; (d) decortication performed; (e) synthetic mineral collagen composite bone graft; (f) adaptation of synthetic mineral collagen composite bone graft on the ridge defect; (g) placement of ribose cross-linked collagen membrane over the grafted region; (h) stabilization of membrane and approximation of flap
Healing was uneventful in the patient. At 14th day, the sutures were removed. After 6 months, a CBCT scan was performed to assess the bone formation. CBCT scan of tooth #9 region revealed increased width of the bone when compared to baseline [Figure 1b ]. The radiographic bone width was 4.8 mm at crest and 7.8 mm and 9.3 mm at 3 and 6 mm levels, respectively. Re-entry surgery was performed for dental implant placement. Midcrestal incision was made using #15 blade and full-thickness mucoperiosteal flap was raised buccally. Mature bone was seen in the augmented region. The implant osteotomy was performed at 850 rpm under copious irrigation. Implant (2.75-mm diameter by 11.5-mm length roughened surface, two-piece implant - JD Icon Ultra. S, JDentalCare, Italy) was placed at prosthetically driven position with 45 Ncm torque at the level of the bone crest. Two-layered suturing technique was performed to achieve tension-free flap closure at the wound margin with Mersilk 4.0, 3/8, reverse cutting nonresorbable sutures (Ethicon, Hamburg, Germany) [Figure 3 ].
Figure 3: Re-entry procedure – Implant placement. (a and b) Alveolar ridge at 6-month postoperative to lateral bone augmentation; (c) Mucoperiosteal flap reflection and visualization of residual alveolar ridge; (d) placement of paralleling pin after implant osteotomy; (e) placement of dental implant; (f) suturing and closure of flap
Bone sample was obtained during implant osteotomy for histopathological analysis. Hematoxylin and eosin-stained hard tissue section showed patches of woven bone with osteocytes and mature bone consisting of resting, reversal lines, and covered by a layer of osteoid in most areas surrounded by fibrous tissue associated with fibroblasts and fibrocytes. The overall picture was suggestive of viable bone [Figure 4 ].
Figure 4: Histopathology of bone sample obtained from augmented site (×20) – viable bone noted
DISCUSSION
The present case report suggests that CBG with RCLM may represent a suitable alternative to existing GBR procedures and materials for lateral bone augmentation. CBG utilized in the present case offers a significant advantage in handling of the material during grafting procedure. Carbon apatite structure of calcium phosphate mineral mimics natural bone in terms of resorption and remodeling, while collagen provides and 3-dimensional structure–both together aids in higher osteoconduction.[ 6 , 7 ] It is known that osteoblasts secrete bone matrix and the freshly formed osteoid which chiefly consists of type 1 collagen, rapidly gets converted to bone by deposition of calcium phosphate crystals within it.[ 8 ] This explains the rationale behind the composition of graft used in the present case report and it can be called as a synergistic combination.
The current case showed satisfactory bone formation with the use of CBG and RCLM. This is in accordance with a recent study that assessed the replacement process of carbon apatite by alveolar bone in rat extraction socket and found that the graft was gradually absorbed by osteoclasts in the extraction socket, which was then easily replaced by alveolar bone. In addition, it was also noted that bone thickness increased with the use of carbon apatite material.[ 2 ] Furthermore, studies have shown that RCLM has the property of ossification during the course of time, which would have contributed positively to the bone formation in the defect site.[ 9 , 10 ] In addition, decortication was performed to ensure better vascularization, which could have added to the result we obtained. A recent systematic study has also reported that decortication in GBR procedure resulted in better bone formation.[ 11 ]
Until now, to the best of knowledge of the authors, there are no controlled clinical trials on the efficacy of synthetic mineral collagen CBG in bone augmentation procedures. Thus, there is a scope of further research in assessing the efficacy of this material in guided bone regeneration procedures.
CONCLUSION
The present case report demonstrated that the use of synthetic mineral collagen CBG along with ribose cross-linked collagen membrane for lateral bone augmentation yielded favorable results.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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