Osseointegration of Dental Implants in Ridges with Insufficient Bones using Different Membranes for Guided Bone Regeneration.

BACKGROUND: The use of membrane with the guided bone regeneration (GBR) has been a controversial aspect of the implant placement, which helps achieve the primary graft stabilization and inhibit early graft loss.
OBJECTIVES: The present clinical trial was aimed to determine the results of GBR with nonresorbable (expanded polytetrafluoroethylene [e-PTFE]) and resorbable (collagen) membrane both clinically and radiographically for 2 years with dental implant placement.
MATERIALS AND METHODS: 16 subjects having 32 sites for implant placement in a split-mouth pattern were included in the study. The sites for implant was prepared and grafted with the autogenous graft procured from the mandibular ramus area followed by graft coverage with either e-PTFE or collagen membrane. Various radiographic and clinical parameters were assessed for 2 years at an interval of 6 months each. The collected data were recorded for each study subject for all the implant sites and were statistically analyzed.
RESULTS: The mean values for periodontal probing depth at 6 months, 12 months, 18 months, and 24 months were 2.25 ± 0.17, 2.67 ± 1.84, 2.64 ± 1.21, and 3.01 ± 0.52, respectively, for the e-PTFE group. For the collagen group, the probing depth mean values at 6 months, 12 months, 18 months, and 24 months were 2.30 ± 0.14, 2.59 ± 1.76, 2.62 ± 1.30, and 2.98 ± 0.81, respectively. The corresponding clinical and radiographic parameters at all time intervals were nonsignificant on the intergroup comparison.
CONCLUSION: Dental implants placed with simultaneous GBR have an acceptable survival rate at the end of 2 years irrespective of the resorbable or non-resorbable membrane used. Copyright:

INTRODUCTION

V arious regenerative membranes and bone grafts are being used for a long time in dentistry for the preservation and augmentation of the alveolar ridge.[1] Furthermore, various modifications and advancements are being introduced in membranes as well as bone grafts. In the recent past, there has been a drastic advancement in the implantology along with the introduction of different bone grafts.[2] These bone grafts are widely used in dental implant placement for bone regeneration, augmentation, and bone preservation.[3] For the success of bone grafting in implant placement assisting the aforementioned procedures, various materials are used.[4] They include allograft, autograft, xenografts, and substitute for bone grafting, synthetic grafts, composite grafts, block grafts, and barrier membranes (resorbable and nonresorbable). Bone morphogenic proteins are also recently approved by the USFDA as a material for bone grafting and sinus augmentation as they show the osteoinductive phenomenon.[5]

The main aim to be achieved with the bone grafting remains the generation of a scaffold strong enough to provide the support for the dental implant osseointegration and preserve the remaining alveolar bone in the socket.[6] To achieve acceptable osseointegration for dental implants is necessary as they restore the speech, phonetics, and esthetics encountered by the people with missing teeth. The success of various bone grafting materials plays a vital role in assessing the implant function in the future.[7]

The use of guided bone regeneration (GBR) in implant placement procedure helps achieve the primary graft stabilization and inhibit early graft loss. 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.[8]

Various resorbable and nonresorbable membranes have shown success when employed in GBR. Expanded polytetrafluoroethylene (e-PTFE) membranes were considered as gold standard for GBR in the early literature.[910] Hence, the present clinical trial was aimed to determine the results of GBR with nonresorbable (e-PTFE) and resorbable (collagen) membrane both clinically and radiographically over 2 years with dental implant placement.

MATERIALS AND METHODS

The present clinical study was carried out on 16 subjects in total. The age range of the study subjects was between 22 years to 68 years with the mean age as 47 years. A total of 32 implants were placed in 16 subjects following a split-mouth pattern. Among 16 subjects, 9 were female and 8 were male. The patients included in the study 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.).

After implant placement, patients were recalled every 6 months for 2 years. The dental implants used were Osstem® having different diameters and lengths depending on the bone availability at the implant site. All the sites were augmented with the autogenous graft procured from the mandibular ramus areas of the subjects intraoperatively. Following graft placement, sites were covered by e-PTFE (Gore-Tex) on one side and collagen membrane Bio-Gide on the other site. Both e-PTFE and collagen were placed on 16 implant sites. The selection as to which site will be treated with collagen or e-PTFE was completely random to avoid bias.

The sites for implant placement were prepared and grafted. Postoperative instruction regarding tooth brushing and oral hygiene maintenance were given along with antibiotics and nonsteroidal anti-inflammatory drugs for 3 days. Surgical reentry to remove e-PTFE was done at the end of 16 weeks for the mandible and 24 weeks in the maxilla. Various radiographic and clinical parameters were assessed for 2 years at an interval of 6 months each. Any exposed membrane or if membrane caused an inflammatory reaction was removed and was not included for the data analysis statistically.

Clinical parameters assessed at recall were probing depth at 4 sites (mesial, distal, buccal, and palatal/lingual) using UNC-15 probe and bleeding on probing at the same four sites. Concerning the radiographic parameters, the level of change in the marginal bone at mesial and distal aspects, changes in bone defects dimensions, and percentage gain in bone were measured and recorded. All the measurements for both the clinical and radiographic parameters were performed by the single operator to avoid interoperator bias. The collected data were recorded for each study subject for all the implant sites and were statistically analyzed (P ˃ 0.05).

RESULTS

The demographic characteristics of the study subjects are summarized in Table 1. The clinical and radiographic parameters were recorded separately for 16 implant sites treated with e-PTFE and other 16 sites treated with collagen membranes. The values of these two groups were statistically analyzed. Clinical parameters such as bone level (marginal) at baseline, changes in bone level (from baseline), and percentage of bone gain (from baseline) are shown in Table 2.

Table 1

Demographic characteristics of the study subjects

Characteristic	Subgroups	Value
Mean age (years)		48.6
Gender	Male (n)	8
	Female (n)	9
Membrane use with GBR	e-PTFE	Nonresorbable membrane
	Biogide™	Resorbable collagen membrane
Number of implants placed	n	32
Implant site	Maxilla	15
	Mandible	11

GBR: Guided bone regeneration, e-PTFE: Expanded polytetrafluoroethylene

Table 2

Clinical parameters

Parameter	Follow up (months)	Group I (with e-PTFE membrane) at 24 months	Group II (with collagen membrane) at 24 months	P
Periodontal probing depth	6	2.25±0.17	2.30±0.14	0.3710
	12	2.67±1.84	2.59±1.76	0.9008
	18	2.64±1.21	2.62±1.30	0.9644
	24	3.01±0.52	2.98±0.81	0.9016
Bleeding on probing sites % (n)	6	59.37% (n=38)	60.93% (n=39)	-
	12	60.93% (n=39)	60.93% (n=39)
	18	56.25% (n=36)	54.68% (n=35)
	24	50.0% (n=32)	48.43% (n=31)

e-PTFE: Expanded polytetrafluoroethylene

About radiographic parameters, the level of change in the marginal bone at mesial and distal aspects, changes in bone defects dimensions, and percentage gain in bone were measured and recorded. All the parameters at all time intervals were nonsignificant on the intergroup comparison. The values of changes in radiographic parameters in the e-PTFE and collagen membrane group are depicted in Table 3.

Table 3

Bone parameter changes

Parameter	Follow up (months)	Group I (with e-PTFE membrane)	Group II (with collagen membrane)	P
Bone level (marginal) at baseline	6	2.198±0.434	2.225±0.257	0.8319
	12	2.227±1.176	2.265±1.802	0.9442
	18	2.183±2.434	2.179±2.348	0.9963
	24	2.461±0.265	2.442±0.301	0.8510
Changes in bone level (from baseline)	6	2.36±0.289	2.38±0.304	0.8500
		2.22±0.174	2.20±0.186	0.7556
		2.21±0.458	2.23±0.120	0.8670
		2.43±0.128	2.42±0.131	0.8286
Percentage of bone gain (from baseline)	6	89.13±0.678	88.88±0.803	0.3489
	12	88.21±1.123	88.18±1.246	0.9434
	18	87.92±1.168	87.86±1.162	0.8852
	24	87.12±0.894	87.11±0.901	0.9751

e-PTFE: Expanded polytetrafluoroethylene

DISCUSSION

The present clinical trial was aimed to determine the results of GBR with nonresorbable (e-PTFE) and resorbable (collagen) membrane both clinically and radiographically for 2 years with dental implant placement. The present trial comprised 16 subjects in total. The age range of the study subjects was between 22 years to 68 years with the mean age of 48.6 years. A total of 32 implants were placed in 16 subjects following a split-mouth pattern. Among 16 subjects, 9 were female and 8 were male. All the sites were augmented with the autogenous graft procured from the mandibular ramus areas of the subjects intraoperatively. Following graft placement, sites were covered by e-PTFE (Gore-Tex) on one side and collagen membrane Bio-Gide on the other site.

Comparable parameters were recorded for both e-PTFE and collagen membranes in simultaneous GBR both clinically and radiographically for 2 years postoperatively. Two other studies were comparable to the present study in terms of follow-up. A review by Sbricoli et al.[6] in 2020 followed up implants with GBR and membranes for their survival rates for 12–59 months. Furthermore, another study had a 1-year follow-up by Benic et al.[11] in 2002. Another study where e-PTFE was used in implants was by Wang et al.7 in 2016.

The present study also assessed the radiographic parameters including the marginal bone level changes, and the values were found nonsignificant at 6 months, 12 months, 18 months, and 24 months with the P values of 0.8319, 0.9442, 0.9963, and 0.8510, respectively. It was observed that the changes occur until 18 months after implant placement and GBR. Thereafter, some amount of bone loss (marginal) was observed in both the groups. The findings of the present study were in agreement with the studies by Zhang et al.[8] in 2019 and Benic et al.[11] in 2009 where marginal bone loss observed was 2.05 mm and 1.83 mm, respectively, in dental implants simultaneously treated with GBR.

Scarce data in the literature comments on the radiographic and clinical parameters after dental implant placement and GBR. Few studies in the literature document no difference in marginal bone levels in dental implants with and without GBR. These findings are similar to the findings of the present study where no changes in the radiographic bone loss (marginal) were observed between the two groups with e-PTFE and collagen membrane. The studies in the agreement were by Wang et al.[9] in 2013 and Blanco et al.[10] in 2005 and Benic et al.[11] in 2009. At 18 months and 24 months recall, slightly higher bone loss was observed with e-PTFE than the collagen membrane. This can be attributed to more membrane exposure and inflammatory reactions seen with e-PTFE than with the collagen membrane. Similar results were reported by the study Donos et al. in 2008 and Zitzmann et al.[1213] in 2013 where more bone loss and more soft-tissue complications were seen with the e-PTFE membrane use.

CONCLUSION

Dental implants placed with simultaneous GBR have an acceptable survival rate at the end of 2 years irrespective of the resorbable or nonresorbable membrane used. The nonsignificant difference was observed between the two groups with and without membrane in both clinical and radiographic parameters. The study had few limitations in terms of the monitoring period, smaller sample size, and histological bone evaluation (considered as gold standard). To reach a definitive conclusion, studies with the larger sample size and longer monitoring periods are warranted.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.