Evaluation of Bone Regeneration around Implants with and Without Flap Elevation.

BACKGROUND: The aim of this study is to clinically evaluate and compare the clinical success and the relative bone healing of the implants which are placed using a flapless procedure and compare it to those placed by the conventional flap technique.
MATERIALS AND METHODS: This study was conducted with ten patients that were randomly divided into two groups. Group A included patients with immediately placed implants after extraction with flap elevation. Group B included patients with immediately placed implants after extraction without any flap elevation. The clinical parameters recorded were Plaque index, Modified Gingival Index, Early Wound Healing Index, Buser's criteria, Distance between implant shoulder and the crestal bone (DIB), and Radiographic Examination in a standardized manner to evaluate changes for the DIB values.
RESULTS: There was an improvement in Plaque Score from baseline to 1 month and baseline to abutment placement (6 months), which was statistically significant, but the plaque score from 3 months to abutment placement (6 months) was statistically nonsignificant in both the group. There was an increase in modified gingival score from baseline to 3 months, baseline to abutment placement (6 months), and 3 months to abutment placement (6 months), which was statistically significant in both the groups. The DIB scores in Group A recorded at baseline to 6 months were 2.80 ± 0.57 and 1.90 ± 0.42, respectively, showing a mean difference of -0.90 and P = 0.001 in comparison. Whereas, the DIB scores in Group B at baseline to 6 months were 3.20 ± 0.57 and 2.50 ± 0.50, respectively, showing a mean difference of -0.70 and P = 0.001 in comparison. The DIC scores in Group A at baseline to 6 months were 1.60 ± 0.54 and 0.00 ± 0.00, respectively, showing a mean difference of -1.60 and P = 0.003 in comparison, Whereas the DIC scores in Group B at baseline to 6 months were 1.40 ± 0.54 and 0.00 ± 0.00, respectively, showing a mean difference of -1.40 and P = 0.005 in comparison.
CONCLUSION: Implants placed in fresh extraction sockets with and without mucoperiosteal flap elevation can be successfully done with augmentation procedures. Short-term survival rates and clinical outcomes of both groups were similar and appeared to be predictable treatment modalities. Copyright:

INTRODUCTION

The First Oral dental implant was done by Branemark et al. in 1965.[12] Nearly after three decades, in 1985, Branemark, Leckholm, and Zarb revolutionized the field of implantology by publishing the implant designs, surgical protocol, and clinical results.[3]

In the original protocol, Adell and Lekholm[3] suggested a 6–12 months wait for healing of the extraction site before implant placement to give time and allow for the complete ossification of the socket. However, this protocol has been challenged within the past two decades by reducing the time between tooth extraction and implant placement. The modified protocol is known as immediate implants. Immediate implants were first clinically described by Schulte.[4]

Brånemark, in the late 1970s, approved the use of extensive flaps to gain access to the surgical field during the implant procedure.[5] In cases with poor bone quantity, the reflection of a mucoperiosteal flap can enable implant settlement by permitting the surgeon to visually calculate bone extent and morphology at the site. Furthermore, this may reduce the risk of the occurrence of bone fenestrations and dehiscences. A study in the year 1970 established a relationship between flap reflection and gingival recession, as well as bone resorption around normal teeth.[5] In addition, it has been reported that the postsurgical tissue loss from flap reflection, suggesting that the use of flap surgery for implant procedure may undesirably influence aesthetics results, particularly in the frontal maxilla. Over 30 years, flap strategies for implant operation have been modified, and more lately, the notion of implant placement without elevation of flap and exposure of the bony tissues was introduced. Flapless surgery had certain advantages, including (1) Decrease of hitches at the patient level, i.e., swelling and pain, (2) Decrease in intraoperative hemorrhage, (3) Decrease of surgical time and need for suturing, (4) Conservation of hard and soft tissues, and (5) Preservation of blood supply. Despite these compensations, the flapless method also has several potential inadequacies. These include (1) The incapability of the surgeon to envisage anatomical benchmarks and important structures, (2) The probability for thermal injury to the bone due to partial external irrigation during osteotomy with guided surgery, (3) Failure to perfectly see the vertical terminus of the implant placement, (4) Reduced access to the bony outlines for alveoloplasty, (5) Difficulties to perform an internal sinus lift with an alleviated template, and (6) Inability to operate the circumferential soft tissues to ensure the perfect dimensions of keratinized mucosa around the implant.[678]

The aim of the present study was to evaluate the clinical performance and bone healing of implants placed in fresh extraction sockets with a flapless procedure compared to those placed using flap elevation.

MATERIALS AND METHODS

A study was conducted with an informed consent which included a total of 10 patients, met the inclusion and exclusion criteria of the study protocol and divided in to 2 groups. Group-A included patients in whom implants were placed immediately after extraction with flap elevation. (Flap Elevation Group). Group-B included patients in whom implants were placed immediately after extraction without flap elevation (Flapless Group). A total of 10 implants were placed. Prior to the commencement of implant surgery a detailed history of the patients was carefully recorded. The inclusion criteria for the study were as follows age group was >20 years; Adequate patient's availability to meet the follow-up schedule; Healthy patient: American Society of Anesthesiologists I and II;[9] Patients with proper oral hygiene (checked by modified gingival index and modified plaque index) Adequate patient compliance; Patients neurologically and hemodynamically stable enough to undergo a lengthy surgical procedure; tooth/teeth indicated for extraction due to root fractures, endodontic failures, caries, periodontally compromised condition; Only Single Rooted Anterior teeth and premolars were included in the study; site indicated for extraction had ≥3 mm of bone beyond the root apex. The exclusion criteria consisted of patients with Uncontrolled Diabetes; Blood Dyscrasias; Patient with Psychiatric disorders; Alcoholic, Drug Abusers, and heavy smokers; Insufficient availability of bone between the apex of the tooth to be extracted and any limiting vital structure (inferior alveolar nerve, mental foramen, maxillary sinus) at the proposed site of implant placement; patient not willing to cooperate for the study.

Presurgical protocol

After an early investigation and treatment discussion, all the nominated patients will be given thorough instructions about plaque control procedures and will be then exposed to full mouth scaling and root planning. The patients who all will meet the inclusion criteria will be recalled after a week to record the preoperative parameters. A detailed case history will be taken, and diagnostic casts will be made. A cone-beam computed tomography will be taken and intra oral periapical radiographs will be taken of the site with a standardized grid.

Surgical procedure

Each case was accurately evaluated with periapical radiographs and computerized tomography where necessary. Subsequent to these analyses, all the patients undertook scaling, root planning, and oral hygiene directives, and any periodontal treatment essential to provide an oral atmosphere more promising to wound healing. Surgical procedure was performed under local anesthesia and in aseptic conditions all the implants used for the study were placed by the same surgeon. The sites were assigned either to the control or test group according to randomization list. The sites in the Group A (Flap Elevation group) received intrasulcular and vertical incisions to raise a mucoperiosteal flap that extended over the mucogingival junction. Subsequently, the implant sites were prepared using the standardized sequence of drills, and the implants were placed into the bone site at the planned depth [Figures 1 and 2]. All the immediate implants in the Group A (Flap Elevation group) were grafted with a bioactive glass (Perioglas™) bone graft material and covered with Resorbable collagen membrane (Healiguide™). Primary soft tissue closure will be achieved on implants.

Figure 1

Radiograph showing implant placement using flap elevation technique at baseline

Figure 2

Radiograph showing bone level of implant placed using flap elevation technique at 6 month

The sites in the Group B (Flapless group) did not receive any incision or flap elevation. The implant sites were prepared with standard drills using the bony walls as a guide. Thereafter, all the sites were grafted by filling the residual alveolus with bioactive glass (Perioglas™) bone graft material and subsequently followed by the implants into the prepared sites [Figure 3]. The surgical site was protected at the level of gingival wound with a Resorbable collagen membrane (Healiguide™). A follow-up was done after 6 months of the procedure and the clinical parameters were measured so as to compare the results [Figure 4].

Figure 3

Radiograph showing implant placement using flapless technique at baseline

Figure 4

Radiograph showing bone level of implant placed using flapless technique at 6 month

On completion after 5 months, the surgical cover screws were removed, and healing abutments were placed. The flaps were then adapted back to positions and sutured to the healing abutments. The implant was said to be a success when there was absence of any mobility and it fulfilled the criteria of Buser et al.[10] Implant was considered to be a failed implant if there was presence of mobility or bone less greater than one-third of entire length though still not mobile.

RESULTS

The intergroup comparison between Group A and Group B for plaque index at baseline, 3 months and at time of abutment placement (6 months) had P = 0.766, 0.763 and 0.686 respectively which was >0.05 and hence were statistically insignificant [Table 1].

Table 1

Inter group comparison of all of the parameters of Group A and Group B (independent t-test)

Group characteristics		n	Mean±SD	SEM	Mean difference	P	Significance
Plaque index baseline	A	5	0.564±0.18	0.082	−0.036	0.766	NS
	B	5	0.600±0.19	0.083
Plaque index 3 month	A	5	0.634±0.18	0.081	−0.034	0.763	NS
	B	5	0.668±0.16	0.073
Plaque index abutment placement	A	5	0.702±0.22	0.098	−0.050	0.686	NS
	B	5	0.752±0.15	0.068
Modified gingival index baseline	A	5	0.598±0.19	0.083	−0.032	0.727	NS
	B	5	0.630±0.07	0.031
Modified gingival index 3 month	A	5	0.672±0.21	0.093	−0.040	0.698	NS
	B	5	0.712±0.08	0.034
Modified gingival index abutment placement	A	5	0.742±0.22	0.098	−0.048	0.656	NS
	B	5	0.790±0.08	0.034
Early wound healing index 1 week	A	5	3.200±0.45	0.200	0.200	0.347	NS
	B	5	3.000±0.00	0.000
Early wound healing index 2 weeks	A	5	2.200±0.45	0.200	0.200	0.608	NS
	B	5	2.000±0.71	0.316
Early wound healing index 4 weeks	A	5	1.400±0.55	0.245	0.200	0.545	NS
	B	5	1.200±0.45	0.200
DIB baseline	A	5	2.800±0.57	0.255	−0.400	0.299	NS
	B	5	3.200±0.57	0.255
DIB abutment placement	A	5	1.900±0.42	0.187	−0.600	0.074	NS
	B	5	2.500±0.50	0.224
DIC baseline	A	5	1.600±0.55	0.245	0.200	0.580	NS
	B	5	1.400±0.55	0.245
DIC abutment placement	A	5	0.000±0.00	0.000	0.000	NP	NP
	B	5	0.000±0.00	0.000

NP: P value cannot be computed because the standard deviations of both groups are 0. SD: Standard deviation, SEM: Standard error of mean, DIB: Distance between implant shoulder and the crestal bone, DIC: Disseminated intravascular coagulation, NS: Not significant

The intergroup comparison between Group A and Group B for modified gingival index at baseline, 3 months and at time of abutment placement had P = 0.727, 0.698, and 0.656, respectively, which was >0.05 and hence were statistically insignificant [Table 1].

The Intergroup comparison between Group A and Group B for early wound healing index at 1 week, 2 weeks and 4 weeks had P = 0.347, 0.608 and 0.545, respectively, which was <0.05 and hence were statistically insignificant [Table 1].

The DIB scores in Group A recorded at baseline to 6 months were 2.80 ± 0.57 and 1.90 ± 0.42, respectively, showing a mean difference of −0.90 and P = 0.001 in comparison. Hence, a gradual decrease in DIB is seen from baseline to 6 months. Also as P ≤ 0.05, it was statistically significant [Table 2]. The DIB scores in Group B at baseline to 6 months were 3.20 ± 0.57 and 2.50 ± 0.50, respectively, showing a mean difference of −0.70 and P = 0.001 in comparison. Hence, a gradual decrease in DIB is seen from baseline to 6 months [Table 3]. On comparison, as P ≤ 0.05, it was statistically significant. The Intergroup comparison of Group A and Group B for DIB scores at baseline and at time of abutment placement (6 months) had P = 0.299 and 0.074, respectively, which was >0.05 and hence was statistically insignificant [Table 1].

Table 2

Intra group comparison of all of the parameters of Group A (flap elevation Group) (paired t-test)

Characteristics	Mean	n	SD	SEM	Mean difference	P	Significance
Plaque index baseline	0.564	5	0.184	0.082	−0.070	0.003	S
Plaque index 3 month	0.634	5	0.182	0.081
Plaque index baseline	0.564	5	0.184	0.082	−0.138	0.010	S
Plaque index abutment placement	0.702	5	0.219	0.098
Plaque index 3 month	0.634	5	0.182	0.081	−0.068	0.054	NS
Plaque index abutment placement	0.702	5	0.219	0.098
Modified gingival index baseline	0.598	5	0.185	0.083	−0.074	0.007	S
Modified gingival index 3 month	0.672	5	0.208	0.093
Modified gingival index baseline	0.598	5	0.185	0.083	−0.144	0.004	S
Modified gingival index abutment placement	0.742	5	0.219	0.098
Modified gingival index 3 month	0.672	5	0.208	0.093	−0.070	0.013	S
Modified gingival index abutment placement	0.742	5	0.219	0.098
Early wound healing index 1 week	3.200	5	0.447	0.200	1.000	0.001	S
Early wound healing index 2 weeks	2.200	5	0.447	0.200
Early wound healing index 1 week	3.200	5	0.447	0.200	1.800	0.001	S
Early wound healing index 4 weeks	1.400	5	0.548	0.245
Early wound healing index 2 weeks	2.200	5	0.447	0.200	0.800	0.016	S
Early wound healing index 4 weeks	1.400	5	0.548	0.245
DIB baseline	2.800	5	0.570	0.255	−0.900	0.001	S
DIB abutment placement	1.900	5	0.418	0.187
DIC baseline	1.600	5	0.548	0.245	−1.600	0.003	S
DIC abutment placement	0.000	5	0.000	0.000

SD: Standard deviation, SEM: Standard error of mean, DIB: Distance between implant shoulder and the crestal bone, DIC: Disseminated intravascular coagulation, NS: Not significant, S: Significant

Table 3

Intra group comparison of all of the parameters of Group B (flapless Group) (paired t-test)

Characteristics	Mean	n	SD	SEM	Mean difference	P	Significance
Plaque index baseline	0.600	5	0.185	0.083	−0.068	0.022	S
Plaque index 3 month	0.668	5	0.163	0.073
Plaque index baseline	0.600	5	0.185	0.083	−0.152	0.003	S
Plaque index abutment placement	0.752	5	0.152	0.068
Plaque index 3 month	0.668	5	0.163	0.073	−0.084	0.001	S
Plaque index abutment placement	0.752	5	0.152	0.068
Modified gingival index baseline	0.630	5	0.069	0.031	−0.082	0.008	S
Modified gingival index 3 month	0.712	5	0.077	0.034
Modified gingival index baseline	0.630	5	0.069	0.031	−0.160	0.003	S
Modified gingival index abutment placement	0.790	5	0.076	0.034
Modified gingival index 3 month	0.712	5	0.077	0.034	−0.078	0.026	S
Modified gingival index abutment placement	0.790	5	0.076	0.034
Early wound healing index 1 week	3.000	5	0.000	0.000	1.000	0.034	S
Early wound healing index 2 weeks	2.000	5	0.707	0.316
Early wound healing index 1 week	3.000	5	0.000	0.000	1.800	0.001	S
Early wound healing index 4 weeks	1.200	5	0.447	0.200
Early wound healing index 2 weeks	2.000	5	0.707	0.316	0.800	0.016	S
Early wound healing index 4 weeks	1.200	5	0.447	0.200
DIB baseline	3.200	5	0.570	0.255	−0.700	0.005	S
DIB abutment placement	2.500	5	0.500	0.224
DIC baseline	1.400	5	0.548	0.245	−1.400	0.005	S
DIC abutment placement	0.000	5	0.000	0.000

SD: Standard deviation, SEM: Standard error of mean, DIB: Distance between implant shoulder and the crestal bone, DIC: Disseminated intravascular coagulation, S: Significant

The DIC scores in Group A at baseline to 6 months were 1.60 ± 0.54 and 0.00 ± 0.00, respectively, showing a mean difference of −1.60 and P = 0.003 in comparison. Hence, a gradual decrease in DIC is seen from baseline to 6 months. Also as P = <0.05, it was statistically significant [Table 2]. The DIC scores in Group B at baseline to 6 months were 1.40 ± 0.54 and 0.00 ± 0.00, respectively, showing a mean difference of −1.40 and P = 0.005 in comparison. Therefore, a gradual decrease in DIC is seen from baseline to 6 months. Also, as P ≤ 0.05, it was statistically significant [Table 3]. The Intergroup comparison of Group A and Group B for DIC scores at baseline had P = 0.580, which was >0.05 and hence was statistically insignificant. For the intergroup comparison of Group A and Group B for DIC scores at abutment placement (6 months). P value could not be calculated because the standard deviation of both the groups was 0 and had a similar mean as well [Table 1].

Buser's Criteria were recorded at the baseline, 3 months, and at the time of abutment placement and all showed negative result.

DISCUSSION

Implant placement without mucoperiosteal flap elevation has not only been recognized as a successful procedure but also as a procedure that reduces postoperative swelling and patient discomfort.[9] Soft-tissue reflection to allow implant placement is generally associated with some degree of bone resorption. This phenomenon may be caused by the micro-architecture of the crestal bone, which is not well vascularized. When soft tissues are elevated, the blood supply to the bone is interrupted, predisposing the crestal (cortical) bone to resorption. In fact, it has been clearly demonstrated that mucoperiosteal flap elevation can stimulate a wound healing process along with the angiogenesis of the vascular plexus and the resorption of the alveolar bone.[1011]

Gomez-Roman[12] placed implants using two types of incisions, i.e., wide flap incision and limited flap incision and found that the interproximal bone loss is less in limited flap incision as there is denudation of the periosteum from the bone when the flap is elevated Sunitha et al.[13] also conducted a study in which implants are placed using flap design in which the interproximal soft tissues are preserved and it showed that there is more bone loss in the conventional flap design as compared to the minimal invasive flap design. Job et al.[14] did a similar study, in which implants were placed using flapless surgery and conventional flap surgery and found that significant bone loss occurs in conventional flap procedure while bone level remains stable in flapless procedure over a period of 3 months. They concluded that in a flapless technique, the intact blood supply from soft tissue facilitates maintenance of nutrition, which is a critical factor in preventing initial bone loss around the implant, while during the flap elevation in conventional flap procedure; the blood supply was disrupted from the bone resulting in lack of nutrition and some amount of initial bone resorption.

Postsurgical soft-tissue loss can result from flap reflection, implying that flap surgery for implant placement may negatively influence the esthetic outcomes. Flapless implant placement can be performed by minimum incision as in a study conducted by Jeong et al.[15] In the flapless approach, surgical trauma is minimal; hence, related postoperative pain and discomfort are greatly minimized. The study by Fortin et al.[16] showed that pain decreased faster with the flapless procedure and the number of patients who felt no pain was higher with the same procedure. Furthermore, the intact periosteum maintains a better blood supply reducing the likelihood of early bone resorption.

Jeong et al.[17] compared the flapless and flap groups and examined the effect of the surgical approach on crestal bone level and osseointegration and found that the mean peri-implant bone height was greater at the flapless sites compared to the sites with flaps. Barros et al.[18] and Fickl et al.[19] observed a loss of bone height at least two times more pronounced in the group where immediate implants were installed after the elevation of mucoperiosteal flap than in the group without flap elevation.

Flapless implantation has several advantages such as decreased surgical time, maintenance of both soft and hard tissues, decreased postoperative bleeding, faster recovery, and patient's comfort, which was also observed and documented in a study by Becker et al.[20]

CONCLUSION

Implants placed in fresh extraction sockets with and without mucoperiosteal flap elevation can be successfully done with augmentation procedures. The findings though being statistically insignificant, suggested more favorable outcomes for the flapless group. Short-term survival rates and clinical outcomes of both groups were similar and appeared to be predictable treatment modalities.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.