Bone Graft and Intraosseous Anchorage of Dental Implants for Reconstruction of the Residual Alveolar Ridge.

BACKGROUND: Bone grafting aims at better dental implant osseointegration and preserves the remaining alveolar bone in the socket. The success of various bone grafting materials plays a vital role in assessing future implant function. AIMS AND
OBJECTIVES: The present clinical trial was aimed at evaluating the results of guided bone regeneration (GBR) with and without the bioresorbable membrane in the dental implant placement.
MATERIALS AND METHODS: The 20 patients were divided into two groups (n = 10). First was Group I- GBR with bioresorbable collagen membrane (BioGide™) and second was Group II- GBR without membrane. Bone gain and bone levels were analyzed for both groups. All the collected data were analyzed statistically.
RESULTS: For Group I, bone levels at baseline were nonsignificant (P = 0.2188) Similarly, nonsignificant values were seen in both groups at 3 months with bone level values of 0.25 ± 0.17 and 0.38 ± 0.24 for Group I and Group II, respectively. Changes in the bone levels were found to be 2.45 ± 0.349 and 2.58 ± 0.304 from Group I and II, respectively, inferring the nonsignificant difference with P value of 0.3723. The percentage of bone gain for intergroup at the end of 3 months was 89.15% ±0.678 for Group I and 88.68% ± 0.503%; these values were statistically nonsignificant (P = 0.982).
CONCLUSION: Nonsignificant difference was observed between the two groups with and without membrane in terms of changes in bone level, percentage of bone gain, and bone defect reduction. This study concludes that the use of bone grafts significantly improves residual alveolar ridge irrespective of membrane used. Copyright:

INTRODUCTION

Osteogenesis, a property of autogenous bone grafts, is the process of bone formation of the bone from the living cells from the host. These living cells include mainly the osteocytes, osteoblasts, and the pluripotent stem cells from periodontal ligament.[1] Osteoinduction is another property shown by the bone grafts where the bone grafts or substitutes and such similar materials show the bone growth induction by proliferating and differentiating the pluripotent stem cells present near the bone into osteocytes and osteoblasts.[2] Osteoinduction is mainly shown by bone morphogenetic proteins, demineralized freeze-dried bone allografts, and autogenous bone grafts. These grafts are mainly from the class of transforming growth factors.[3] Synthetic bone graft materials and xenografts show the property of osteoconduction where bone formation is initiated from the viable cells present in the surrounding bone. Synthetic bone grafts and xenografts help in bone deposition. This bone deposition is replaced by the bone from the host for the time.[45]

Various combinations of the osteoinductive and osteoconductive bone graft materials have been used in dentistry to get the advantageous properties of both the bone grafts. The choice is largely based on the clinician's perspective than on the scientific approach.[6]

Guided bone regeneration (GBR) is a basic and advantageous phenomenon used in implant dentistry. GBR assists in the process of implant placement at the sites with less than adequate bone for supporting implants.[7] The use of membrane with the GBR has been a controversial aspect of the implant placement. The use of GBR in implant placement procedure helps achieve the primary graft stabilization and inhibit early graft loss.[8]

The choice of appropriate bone graft depends on various factors. The factors governing this are particle size, defect size, bone architecture, and procedure to be done. For GBR, the choice of adequate bone graft is a difficult task for the clinician.[9] This is governed by the rationale and particle size of the bone graft used. To make the selected bone graft ideal for the procedure, autogenous bone grafts are considered best. Autogenous bone grafts were prepared from the iliac crest of the patients and constituted the hydroxyapatite and β-tricalcium phosphate.[10] The literature reports in various studies that the use of the membranes with GBR has better results and advantages over the nonusage of membranes.[11]

The present clinical trial was aimed at evaluating the results of GBR with and without the bioresorbable membrane in the dental implant placement.

MATERIALS AND METHODS

The present clinical trial was carried out on 20 patients of both genders within the age range of 20–60 years, with a mean age of 36.8 years. The selected patients had residual alveolar ridge deficiency and required GBR for dental implants' placement. All selected patients received dental implants from the same operator. Ethical clearance was taken from the ethical committee review board of the institution. The patients included did not have any systemic condition that might affect the implant placement, implant success (osseointegration) or contraindicate local anesthesia, and surgical therapy in the long run such as diabetes mellitus, hypertension, cardiac conditions, hematological disorders, and a disease affecting bones (arthritis, Paget's disease, etc.)

The included patients had defect dimensions between 1 mm and 7 mm. Furthermore, current smokers were not included in the study. The 20 patients who fulfilled all the mentioned criteria were divided into two groups. Group I patients underwent GBR using autologous hydroxyapatite ad beta-tricalcium phosphate bone graft with bioresorbable collagen membrane (BioGide™). Group II patients underwent GBR before implant placement without any membrane. Group I had six males and four females, whereas, Group II had seven females and three males. This gender inclusion was completely randomized to avoid any bias in the study.

For presurgical preparation, all patients were made to rinse with 0.2% chlorhexidine for 30 s. Implants in both the groups were placed by the single operator raising full-thickness flap. With a calibrated periodontal probe, all four dimensions of the exposed vertical defects were measured including buccal, lingual, distal, and mesial. In Group I, BioGide (the resorbable collagen membrane) was used to cover the autogenous graft, followed by closure with the Vicryl suture (Ethicon 4-0). For Group II, no membrane was used, only flap adaptation and closure was done with Vicryl sutures as in Group I. Postoperative instruction regarding oral hygiene and healing was instructed; antibiotics and analgesics were prescribed for 3 days. After 1 week, sutures were removed and any surgical complication was recorded if present.

The stability of implants was measured and using the same method as employed at the time of the GBR, the periodontal probe was used to measure defect from all four sites (buccal, lingual, distal, and mesial). Bone gain and bone levels were analyzed for all the patients of both groups.

The data were collected individually for all the study participants in terms of mean and standard deviations. All the collected data were analyzed statistically. The level of significance was kept at the value of P ˃ 0.05.

RESULTS

The present clinical trial was aimed at evaluating the results of GBR with and without the bioresorbable membrane in the dental implant placement. The demographic characteristics of the study participants are summarized in Table 1

Table 1

Demographic characteristics of the study participants

Characteristic	Group I	Group II
Mean age (in years)	43.7	51.1
Gender
Male (n)	6	4
Female (n)	3	7
Membrane use with GBR	BioGide™ (resorbable collagen membrane)	None
Number of implants placed (n)	14	15
Implant site
Maxilla (n)	6	7
Mandible (n)	8	8

GBR: Guided bone regeneration

The percentage of bone gain for both groups was assessed at 3 months from baseline values. All values were statistically analyzed using one-way ANOVA and statistical significance was kept at P ˃ 0.05. These values are summarized in Table 2.

Table 2

Bone parameters assessed

Parameter	Group I (with membrane)	Group II (without membrane)	P
Bone defects (at baseline during GBR)	2.201±0.168	2.325±0.257	0.2188
Bone defects at 3 months surgical re-entry	0.25±0.17	0.38±0.24	0.1756
Changes in bone level at 3 months	2.45±0.349	2.58±0.304	0.3723
Bone gain percentage at 3 months	89.15±0.678	88.68±0.503	0.0982

GBR: Guided bone regeneration

However, changes in the bone levels on intragroup comparison from baseline to 3 months showed significant improvement for both the groups with P < 0.0001. Concerning the postoperative complications assessed, one patient in Group I showed wound dehiscence and suture loss after 2 days of implant placement and GBR in the mandibular anterior region. However, no surgical intervention was needed and the defect was treated well conservatively with uneventful healing with adequate bone gain. For Group II, two patients reported continuous pain at the implant site at the maxillary anterior region and premolar region. In one patient, the pain was relieved with anti-inflammatory analgesics after 3 days, whereas another patient showed a failure to osseointegrate and was not included in statistical analysis.

DISCUSSION

The present clinical trial was aimed at evaluating the results of GBR with and without the bioresorbable membrane in the dental implant placement. The percentage of bone fill at 3 months was 89.15 ± 0.678 and 88.68 ± 0.503, respectively, with P = 0.0982 which was nonsignificant. These findings suggest sufficient and significant bone gain in both the groups with the graft irrespective of the membrane use. One such study was conducted by Funato et al.[12] in 2013 where authors suggested a significant bone gain of 8.6 mm with only one graft with the use of growth factors, ramus bone graft, and bovine bone. Another study by Beitlitum et al.[13] in 2010 showed a bone gain of 5.63 mm with a collagen membrane compared to 4.25 mm without collagen membrane.

Various studies have reported that greater wound opening is encountered with the use of membranes. Studies by Moses et al.[14] in 2005 showed that wound exposure with membrane use may result in fewer tissues peri-implant and might decrease the regeneration of alveolar bone by 80% around the dental implants. These results were contradictory to the present trial where only one patient presented with early wound opening and that too was managed uneventfully with successful osseointegration conservatively. These findings of the present study were consistent with the study of Gotfredsen et al.[15]

The results of the present study showed that there was a significant gain in the bone from baseline to the 3 months post-GBR with BioGide resorbable collagen membrane as well as without using membrane. However, when compared intergroup between Group I and Group II, the gain in bone was statistically nonsignificant with P = 0.0982. One such study was done by Aaboe et al.[16] in 2000 where the authors reported that regarding the buccal dehiscence type defects higher gain in alveolar bone was seen in patients in whom the membrane was not used with GBR compared to the membrane. In contrast, various other studies were like Rasmusson et al.[17] in agreement with the present trial where similar results were reported.

CONCLUSION

The present study shows a significant reduction in bone defect and significant bone gain after GBR. However, the use of the membrane does not govern this improvement in the bone parameters. The nonsignificant difference was observed between the two groups with and without membrane in terms of changes in bone level, percentage of bone gain, and bone defect reduction. This study concludes that the use of bone grafts significantly improves residual alveolar ridge irrespective of membrane used.

The study had few limitations in terms of the monitoring period, smaller sample size, and histological bone evaluation which are considered as the gold standard. To reach a definitive conclusion, studies with a larger sample size and longer monitoring periods are warranted.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.