Evaluation of papilla levels following three different techniques for the second stage of implants - A clinical and radiographic study.

OBJECTIVE: Papilla formation after placement of an implant is influenced by the underlying bone and the periodontal biotype. The second-stage surgery to uncover the implants may have an effect on the regeneration of papilla and various techniques such as the scalpel, diode laser, and punch technique are used. In the present study, an attempt has been made to evaluate papillary fill levels following three different techniques of second-stage implant surgery.
MATERIALS AND METHODS: A total of 35 patients with 45 implants (39 single implants and 3 sites with two adjacent implants) were randomly divided into three groups with 15 implants each: second-stage implant surgery with midcrestal incision using scalpel (Group I), with I-shaped incision using scalpel (Group II), and using diode laser (Group III). The mean papillary fill and mean crestal bone loss for all three groups were compared at baseline, 3 months, and 6 months of prosthesis delivery.
RESULTS: Complete papilla fill at 6 months was seen in 60% and 73.3% of sites in Group II and Group III, respectively. Bone level contacting implant and adjacent teeth was less in both Groups II and III. Bone level from the contact point to the bone crest was least in Groups II and III.
CONCLUSION: The use of diode laser during second-stage surgery showed maximum papillary fill and minimal crestal bone loss when compared with other two techniques. Irrespective of technique used for second-stage surgery, bone loss did occur after prosthesis delivery. Copyright:

INTRODUCTION

The primary goal of implant therapy is the provision of a restoration that reconstructs the form, function, and esthetics of the edentulous spaces.[1] The success of single-tooth replacement is influenced by implant survival factors that include changes in marginal bone level at the teeth adjacent to the implant, soft-tissue (ST) measurements, prosthetic complications, and esthetic measurements.[2] An emergence profile that creates a harmonic contour of the gingival margin at the level of ST needs to be formed after replacement with implants.[3] The papilla plays a protective role in the adjacent periodontium, including the alveolar bone crest, acting as a biological barrier against external aggressors and preventing food impaction. The level of the papilla is influenced by the interproximal bone between the implant and the tooth.[4] The papilla around implants should be regenerated not only to achieve optimal esthetics but also for adequate function as sluiceways preventing food impaction.[5]

When the implant is exposed to the oral cavity, changes in the peri-implant bone are seen primarily because of the creation of a biologic width like that of a natural tooth. Initial peri-implant bone loss has also been attributed to numerous other secondary factors, such as mechanical stress caused during implant insertion, periosteal reflection during second-stage surgery, implant collar design, and the presence of a microgap at the implant-abutment interface.[6] Peri-implant crestal bone loss of 1.5–2 mm is expected during the first year of loading, followed by 0.2 mm of bone loss every additional year for two-piece dental implants that are in function.[789]

Papilla formation in implant dentistry is known to be influenced by the underlying bone and the periodontal biotype.[10] During the second stage-implant surgery, the ST surgery which is performed to uncover the implant may have an effect on the regeneration of papilla. Various techniques like the use of a scalpel, diode laser, and the punch technique are mentioned in the literature for uncovering implant in two-stage surgery. The use of full-thickness flaps during second-stage surgery has reported to cause significant crestal bone loss.[1112] To overcome this, modifications have been suggested, which include the use of papilla preservation technique by the use of U-shaped incision, use of punch technique, I-shaped incision, and the use of laser. Studies to assess the difference in crestal bone levels after second-stage surgery with scalpel and use of laser do exist. However, the aim of the present study was to evaluate the papillary fill along with crestal bone levels using three techniques, i.e., midcrestal incision using a scalpel, I-shaped incision using scalpel, and laser for second-stage surgery.

With this background, the purpose of this prospective clinical study was to compare the papillary levels with three techniques in second-stage implant surgery in a 6-month clinical trial.

MATERIALS AND METHODS

The study participants were selected from patients reporting to the outpatient department of implantology. The study was performed in accordance with the Declaration of Helsinki, as revised in 2000, and was approved by the institutional ethical committee. All the patients were informed about the study and written informed consent was obtained. Thirty-five patients who had already received 45 implants among which 39 were single implants and 3 were multiple two adjacent implants (MIS SEVEN Implant system) were included in the study. The present investigation was designed as a prospective single-blinded study at the time of second-stage (uncovering of implant) surgery. All implants were placed 4 months prior to uncovering in the mandible and 6 months prior to uncovering in the maxilla. Patients of both sexes (21 females and 24 males) in the age range of 23–59 years and those who had adequate keratinized gingiva (this was assessed by measuring from ST margin to the mucogingival junction using calibrated WHO probe by roll technique. A measurement of ≥2 mm was considered adequate) were included in the study. Implant sites with acute infection, pregnant women, and lactating women were excluded from the study.

All the patients were randomly allocated into three groups by the lottery method.

Group I – Mid crestal incision using scalpel (15 patients)

Group II/I – Shaped incision using scalpel (15 patients)

Group III – Incision using diode laser (15 patients).

A single examiner (KA) performed the second-stage surgery for all the groups. The clinical and radiographic parameters were assessed by another examiner (P) who was blinded with the type of second-stage surgery.

For implants in Group I, second-stage implant surgery was performed using scalpel with midcrestal incision continued with intrasulcular incisions at the adjacent teeth. After the flaps were reflected, conventional healing abutments were placed and the flaps were sutured with 4-0 silk sutures [Figure 1a].

Figure 1

Showing the three methods for second-stage implant procedure and the papilla fill with the corresponding procedures; (a) Uncovering using midcrestal incision and papilla fill at 6 months after prosthesis delivery; (b) Uncovering using I-shaped incision and papilla fill at 6 months after prosthesis delivery; (c) Uncovering using diode laser and papilla fill at 6 months after prosthesis delivery

For implants in Group II, the implants were exposed using an I-shaped incision which is a modification of U-shaped incision given by Shahidi et al. 2008.[13] An I-shaped incision was given by giving two horizontal incisions with a 15# blade mesiodistally 0.5–1.0 mm from labial border of the implant, i.e., one horizontal incision on the labial side and the other on the palatal/lingual side. Another incision was given buccolingually perpendicular to the two horizontal incisions over the midline. The flap was reflected with care and healing abutments were placed. Care was taken to protect the reflected flaps and they were folded adjacent to healing abutment and flap was allowed to heal without sutures [Figure 1b].

The implants in this group were uncovered using the diode laser (AMD Picasso Dental Diode Laser). It is made of gallium–aluminum–arsenide semiconductor of wavelength 810 nm and is used in a continuous mode with a power of 2W. The application fiber is of 300 μm diameter and it is used in continuous wave with contact mode which eliminates the bacteria on the implant surface. The implant sites were assessed and LASER was used to create a small hole, the size of which was increased to expose any part of the cover screw. Intermittent application of the laser was used every 20–30 s to visualize the burning effects of the gingiva. Ablation of the tissues was performed until the surgical opening was sufficient enough to facilitate the removal of the cover screw and replace it by healing abutment [Figure 1c].

All the patients were recalled after 2 weeks to check for the healing process and the prosthetic procedures were then carried out. The impressions were made by the closed tray technique using elastomeric impression materials. All the patients received conventional abutments. Permanent restorations were then fabricated and were delivered to the patients. Following placement of the permanent restoration, all the clinical and radiographic measurements were recorded. These measurements were considered as the baseline measurements (they are mentioned in each table) and they were repeated at 3 months and 6 months after prosthesis delivery. Modified plaque index (mPI), modified gingival index (mGI), Jemt index, and gingival biotype were the clinical parameters assessed. For radiographic analysis, intra-oral periapical radiographs were taken for each selected site using the long-cone paralleling technique using a film holder, with an “E” speed film mounted with mm grid scale.[14]

The following measurements were made to measure the amount of bone loss adjacent to implants. The horizontal measure of the implant shoulder at the fixture abutment junction (FAJ) was taken as a reference line to calculate the vertical measures and all the radiographic parameters listed below were measured using Image Analysis software[15] [Figure 2a].

Figure 2

showing the radiographic measurements made. (a) Schematic diagram showing measurement of radiographic parameters; (b) ImageJ analysis

The vertical distance from the shoulder of the implant (FAJ) and the most coronal part of bone contacting the implant was designated as FAJ-I

The vertical distance from the shoulder of the implant and the most coronal part of bone facing the adjacent tooth was designated as FAJ-Adj

The distance from the shoulder of the implant to the coronal papilla level was noted as ST height

The vertical distance from the crest of the bone to the contact point (CP) is CP-Bone crest.

All radiographic measurements such as FAJ-I, FAJ-Adj, ST height, and CP-Bone crest were carried out using software, ImageJ, which was designed by the National Institute of Health, USA, as shown in Figure 2b. The scale tool in the software was used, it was binarized and checked again for further readings.

Statistical analysis

The sample size was calculated using formula, n = 2 (Z1 + Z2)2 σ2 ÷ d2; where n = total sample size, Z1 = 0.8416 (80% power), Z2 = 1.96 (95% confidence limit), σ = 0.316 (anticipated standard deviation) and d = 0.89 (mean of test value of difference).

Intergroup comparison for clinical parameters (crestal bone levels) at baseline, 3 months, and 6 months was done using one-way ANOVA. Statistical significance was evaluated using post hoc power analysis by Tukey test. Papilla fill was assessed using frequencies in all the three groups. McNemar test was used to assess the effect of biotype on papilla fill. Intragroup analysis was done at baseline, 3 months, and 6 months using paired t-test. P < 0.001 was considered as statistically significant. Intragroup comparison of mPI and mGI at different time periods was done using paired t-test. Statistical software SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. was used for all the statistical calculations.

RESULTS

A total of 35 patients, with 45 implants were included in the study. Of the 45 implants, 39 were single implants and 3 had 2 adjacent implants placed. Of 35 patients, 21 were females (46.6%) and 24 were males (53.3%). The study participants were aged between 23 and 59 years, with the mean age of the patients in all the three groups being 36.22 ± 9.88 (P = 0.177, NS).

Of the 45 implants placed in the 35 patients, 36 (80%) were in the mandible and 9 (20%) were in the maxilla sites; there was no difference between implant sites in all the three groups (P = 0.245, NS). Most of the implants were placed in the mandible in the region of 36 in all the three groups.

When clinical parameters mGI and mPI were assessed, all the three groups showed a statistically significant difference from baseline to 3 months and baseline to 6 months (P < 0.001). Within the group, in the group where midcrestal incision was given, there was no statistically significant change from baseline to 3 months and 6 months, and hence, P value was not applicable.

Crestal bone fill, papilla fill and gingival biotype were also assessed. Inter- and intragroup comparisons for the same were made. Location comparisons based on the implants in maxilla/mandible and anterior/posterior region were also made. The diameters of the implant were also taken into consideration.

Among the 45 implants placed, only 2 implants were in the anterior region, it was noted that in the anterior region, 100% of the sites showed complete papilla fill at all the time periods. However, no difference was noted in crestal bone levels in anterior or posterior teeth at all time periods.

Intergroup comparison of crestal bone levels has been depicted in Table 1. For single implants, when crestal bone levels were compared between three groups, it was observed that there was a statistically significant difference in the mean crestal bone level as measured from FAJ-I, at baseline and 3 months in all the three groups. However, no change was observed at the end of 6 months.

Table 1

Intergroup comparison of crestal bone levels between the three groups at baseline, 3 months and 6 months

Radiographic parameters	Groups			Significance
	I (n=15)	II (n=15)	III (n=15)	ANOVA	Post hoc
FAJ – I
Baseline	2.12±0.32	1.47±0.34	0.09±0.32	t=43.452 ≤0.001	<0.001* 0.001** <0.001***
3 months	2.35±0.33	1.84±0.54	1.48±0.31	t=26.005 ≤0.001	0.003* 0.042** <0.001***
6 months	2.41±0.27	2.13±0.63	2.03±0.45	t=25.136 0.105	0.29* 0.826** 0.099***
FAJ – Adjacent
Baseline	1.68±0.30	1.59±1.07	1.03±0.43	t=24.756 <0.001	0.932* 0.082** 0.037***
3 months	2.03±0.31	1.74±0.99	1.56±0.43	t=25.122 0.009	0.461* 0.735** 0.138***
6 months	2.12±0.42	1.89±0.99	1.64±0.34	t=25.654 0.01	0.602* 0.555** 0.123***
Soft tissue height
Baseline	4.62±0.72	5.03±0.32	5.43±0.27	t=10.503 <0.001	0.063* 0.073** <0.001***
3 months	4.42±0.71	4.84±0.35	5.12±0.24	t=25.118 0.001	0.061* 0.25** 0.001***
6 months	4.21±0.86	4.68±0.36	4.98±0.20	t=23.506 0.002	0.064* 0.307** 0.001***
CP – bone crest
Baseline	5.97±0.7	5.25±0.69	4.44±1.27	t=26.754 <0.001	0.104* 0.056** <0.001***
3 months	5.97±0.93	5.63±0.63	5.13±1.21	t=26.133 0.133	0.595* 0.343** 0.055***
6 months	6.08±0.94	5.87±0.80	5.46±1.19	t=27.332 0.236	0.829* 0.51** 0.217***

*Group I – Group II; **Group II – Group III; ***Group I – Group III. P<0.001 was considered as statistically significant. FAJ – Fixture abutment junction; CP – Contact point; n – number of implants; t – test statistic value

Crestal bone loss as measured from FAJ-Adj showed statistically significant differences at baseline, in groups with midcrestal incision and laser. However, no difference was noted in the three groups at 3 and 6 months. There were statistically significant differences noted for ST height at baseline, 3 months, and 6 months in Group I and Group III. However, there were no statistically significant differences noted in Groups I and II and II and III at all the time periods.

Depending on the location of implant placement either in the maxilla or mandible, percentage of sites with papillary fill and mean crestal bone levels as measured radiographically as FAJ-I, FAJ-Adj, ST height, and CP-bone crest was not statistically different at all time periods.

When crestal bone levels are compared within each group, in Group I, there was a statistically significant difference between the parameters FAJ-Adj and ST height between baseline to 3 months and baseline to 6 months (P < 0.001), as shown in Table 2. In Group II, there was a statistically significant difference between the parameters FAJ-I between baseline to 3 months and baseline to 6 months and ST height between all the time periods (P < 0.001), as shown in Table 2. In Group III, there was a statistically significant difference of FAJ-I from baseline to 3 months and baseline to 6 months (P = 0.002), as shown in Table 2.

Table 2

Intragroup comparison of differences of crestal bone level from baseline to 3 months and 6 months in Group I, Group II and Group III

Groups	Radiographic parameters	Difference between different time periods	Mean difference	t-test	P
Group I	FAJ - I	3 months - Baseline	−0.211	−3.16	0.007
		6 months - Baseline	−0.276	−2.174	0.047
		6 months - 3 months	−0.065	−0.809	0.432
	FAJ - Adjacent	3 months - Baseline	−0.349	−4.243	0.001
		6 months - Baseline	−0.441	−3.801	0.002
		6 months - 3 months	−0.092	−0.769	0.455
	Soft tissue height	3 months - Baseline	0.198	9.539	<0.001
		6 months - Baseline	0.413	8.243	<0.001
		6 months - 3 months	0.214	4.125	0.001
	CP - Bone crest	3 months - Baseline	−0.006	−0.039	0.97
		6 months - Baseline	−0.116	−0.735	0.475
		6 months - 3 months	−0.11	−0.846	0.412
Group II	FAJ - I	3 months - Baseline	−0.369	−3.687	0.002
		6 months - Baseline	−0.663	−4.561	<0.001
		6 months - 3 months	−0.293	−2.871	0.012
	FAJ - Adjacent	3 months - Baseline	−0.154	−2.054	0.059
		6 months - Baseline	−0.301	−2.609	0.021
		6 months - 3 months	−0.147	−1.813	0.091
	Soft tissue height	3 months - Baseline	0.196	5.672	<0.001
		6 months - Baseline	0.353	10.659	<0.001
		6 months - 3 months	0.156	5.718	<0.001
	CP - Bone crest	3 months - Baseline	−0.375	−2.475	0.027
		6 months - Baseline	−0.615	−3.664	0.003
		6 months - 3 months	−0.239	−1.764	0.1
Group III	FAJ - I	3 months - Baseline	−0.494	−6.664	<0.001
		6 months - Baseline	−1.039	−9.244	<0.001
		6 months - 3 months	−0.545	−5.783	<0.001
	FAJ - Adjacent	3 months - Baseline	−0.533	−7.548	<0.001
		6 months - Baseline	−0.611	−4.35	0.001
		6 months - 3 months	−0.077	−0.674	0.511
	Soft tissue height	3 months - Baseline	0.311	4.363	0.001
		6 months - Baseline	0.45	9.346	<0.001
		6 months - 3 months	0.139	2.371	0.033
	CP - bone crest	3 months - Baseline	−0.69	−2.806	0.014
		6 months - Baseline	−1.019	−4.368	0.001
		6 months - 3 months	−0.328	−4.461	0.001

P<0.001 was considered as statistically significant. FAJ – Fixture abutment junction; CP – Contact point; P – Calculated probability

When papillary fill was compared between the three groups, it was observed that 60% and 73.3% of the sites in the Group II and Group III showed complete papilla fill at 6 months, as shown in Table 3.

Table 3

Intergroup and intragroup comparison of papillary fill score (Jemt) on mesial and distal sides between groups

Groups	Jemt Scores	Mesial, n (%)			Distal, n (%)
		Baseline	3 months	6 months	Baseline	3 months	6 months
Group I (n=15)	0	-	-	-	-	-	-
	1	3 (20)	3 (20)	3 (20)	3 (20)	3 (20)	3 (20)
	2	10 (66.6)	12 (80)	12 (80)	10 (66.6)	12 (80)	12 (80)
	3	2 (13.3)	-	-	2 (13.3)	-	-
Group II (n=15)	0	-	-	-	-	-	-
	1	-	-	-	-	-	-
	2	6 (40)	6 (40)	6 (40)	6 (40)	7 (46.6)	7 (46.6)
	3	9 (60)	9 (60)	9 (60)	9 (60)	8 (53.3)	8 (53.3)
Group III (n=15)	0	-	-	-	-	-	-
	1	1 (6.66)	1 (6.66)	1 (6.66)	1 (6.66)	1 (6.66)	1 (6.66)
	2	2 (13.3)	3 (20)	3 (20)	4 (26.6)	4 (26.6)	4 (26.6)
	3	12 (80)	11 (73.3)	11 (73.3)	10 (66.6)	10 (66.6)	10 (66.6)

n – number of implants

Interimplant parameters were assessed separately in each group. The number of sites with papilla fill between two adjacent implants in Group I and Group III is shown in Table 4. The four radiographic parameters for crestal bone levels when assessed between two adjacent implants, it was observed that ST height was more and other three parameters were less in Group III.

Table 4

Comparison of papillary fill index between Group I and Group III on mesial and distal sides of two adjacent implants

Sites with 2 adjacent implants n (3) and group	Jemt scores			Biotype
	Baseline	3 months	6 months
Group I - 45/46 (tooth number)	1	1	1	Thick
Group III - 46/47 (tooth number)	3	3	3	Thick
Group III - 36/37 (tooth number)	1	1	1	Thick

n – Number of sites with adjacent implants

It was also noted that the diameter of the implant did not affect the papilla fill with no difference in the papilla fill and crestal bone level from baseline to 3 and 6 months.

Thick biotype was observed in 31 implant sites (68.9%), whereas thin biotype was seen in remaining implant sites (31.1%). The papillary fill between thick and thin biotype in all the groups were assessed. There was no statistically significant difference between thick and thin biotype in all the three groups (P = 0.484). There were no statistically significant differences noted for gingival biotype with respect to papillary fill and crestal bone levels in anterior (n = 02) and posterior teeth (n = 43), as the number of implants placed in the anterior region was less. Similarly, there was no statistically significant difference noted for gingival biotype in the maxilla and mandible with respect to papillary fill and crestal bone loss.

DISCUSSION

Crestal bone is an important indicator for implant health, and the preservation of crestal bone is essential for the success of dental implants.[16] The height of the papillae between implant and adjacent tooth or between implants is related to the interproximal crestal bone levels. Hence, the preservation of the papillae height and crestal bone is crucial for successful esthetic and functional outcomes of implant treatment. The maintenance of optimal oral hygiene is also essential in implant patients during all the phases. In the present study, patients were followed at 1, 3, and 6 months after Stage 1 implant surgery, wherein oral hygiene instructions were reinforced and care was taken to maintain fair oral hygiene.

The use of I-shaped incision and diode laser for exposure of implant in the present study has shown to reduce the scores of mPI and mGI from baseline when compared with the midcrestal incision (mean difference of 0.44 for I-shaped incision and 0.11 for diode laser). This reduction in the scores could possibly be because of an increase in the papilla height which would reduce the plaque accumulation. Similar improvement in plaque scores (mean difference of 0.58 for U-shaped incision) was noted when a U-shaped incision was used.[13]

Significant volume of crestal bone loss is seen in the early phase of healing that is within 1 year after implant placement which accounts to 1.5–2 mm in the 1st year followed by 0.2 mm annually, and this has been observed in long-term studies.[78] When crestal bone loss occurs, the ST, i.e., the papillae, would also recede, leading to plaque accumulation and unesthetic appearance. One of the reasons could be attributed to the type of incision design in second-stage implant surgery. In the present study, crestal bone height and papilla fill were assessed at the baseline (on the day of prosthesis delivery), 3 months, and 6 months using three different incision designs for second-stage surgery.

The bone quality varies in maxilla and mandible and in anterior and posterior teeth due to difference in the density of bone, it being more cancellous in the maxilla. To avoid the confounding effect of occlusal loading on crestal bone resorption, all patients were given the superstructure according to delayed loading protocol, thus standardizing the loading protocol. In the present study, the lesser mean difference was noted for all the parameters of crestal bone loss at 6 months after prosthesis delivery. These differences cannot be attributed to type of exposure of implant, as the total number of implants placed in the maxilla was 9, and hence, the number in each group was less. Similar results were found in the longitudinal study by Cochran et al. 2009.[17] Furthermore, the mean crestal bone loss for anterior and posterior regions differs with a mean difference of 1.2 mm. The papilla fill around implants depends on the diameter of implants in the anterior region. In the present study, complete papilla fill was seen in the anterior region (both mesial and distal), and in 35% and 46.5% of mesial and distal sides, respectively, complete fill was seen in the posterior region at 6 months. The difference in percentage of the papilla fill in the present study could be because of the less number of implants placed in the anterior region (n = 2).

In the present study, the patients were randomly allocated into three groups by the lottery method based on implant uncovering technique using either scalpel with midcrestal incision, scalpel with I-shaped incision, or using diode laser. All the parameters assessed showed increased values in the group with midcrestal incision compared to I-shaped incision and diode laser at 6-month follow-up (P ≤ 0.002). The crestal bone which is in contact with adjacent teeth (FAJ-Adj) influences the interproximal ST dimensions between the implant and natural teeth. Similar results have been obtained by Choquet et al. in 2001 who said that the amount of bone loss occurring with the use of mid crestal incision is said to be ≥0.5 mm when compared with techniques that involve modification of incisions.[15] In the present study, it shows that the parameter, i.e., bone level contacting adjacent teeth, was higher in midcrestal incision than I-shaped incision and diode laser [Table 1]. When crestal bone loss occurs, the distance from the CP to the bone crest increases which leads to receding of peri-implant papilla leading to unesthetic appearance. Complete papilla fill was not seen in any of the patients in whom midcrestal incision was given, whereas 60% and 73% of the sites in patients with I-shaped incision and diode laser, respectively, showed complete papilla fill at the end of 6 months [Table 3]. There was no difference in the number of sites with 50% papilla fill in any of the groups at any time period.

Various modifications of incisions in second-stage implant surgery have been tried and a comparison of crestal bone levels has been done. One of the techniques used was the Punch technique and was compared to using the mid crestal incision. A mean difference of bone loss between two groups was 0.49 ± 0.96 mm at the time of crown placement and 0.83 ± 1.23 mm after 1 year of crown placement indicating a lesser degree of bone loss in punch technique in the second stage surgery.[18] Shahidi et al. in 2008 used a U-shaped incision and observed that the mean difference of bone loss between two groups (midcrestal and U-shaped incision) was 0.1 mm at 3 months after crown delivery and 0.02 mm at 6 months after crown delivery.[13] The present study showed that ST height in I-shaped incision was 0.353 at 6 months. Similar results were obtained with U-shaped incision.[13] Reduced bone loss and increased papilla fill in the modified techniques could be because the papillae are preserved, and hence, their nutrition is not disturbed; and no sutures are required after second-stage implant surgery. There have been no studies comparing I-shaped incision for second-stage surgery except for a case report. Hence, it was not possible to make any comparison.

Yeh et al., in 2005, were the first to use diode laser for uncovering implants.[19] Martin in 2004[20] and Lung et al. in 2012[21] used erbium (Er), chromium, and yttrium–scandium–gallium–garnet (YSGG) laser for second-stage surgery and observed that tissue stability appeared to be enhanced. Gianfranco et al. in 2010 compared Er: YAG laser and diode laser for exposure of implants and found that Er: YAG laser is known to modify titanium surfaces irrespective of power setting and also higher depth of penetration.[22] Diode LASERs are known to provide sufficient power to modify the ST in and around the implant for uncovery during the second-stage procedure. They help in alteration of the gingival margin, thereby improving esthetics, all while operating within the temperature range so that there is no negative effect to the bone around the implant. Furthermore, with the use of LASER, coagulation can be controlled. Hence, diode laser was used using the same wavelength and same power for all the patients in the present study.

El-Kholey in 2014 did a comparative study on the use of diode laser and reported that the use of diode laser reduces postoperative pain and discomfort, less chances of swelling and hematoma, and need for anesthesia is less.[23] In the present study, there was a statistically significant difference (P ≤ 0.001) of mean crestal bone loss at baseline, 3 months, and at 6 months between midcrestal incision and diode laser. The mean difference of all radiographic parameters from baseline to 3 months and 6 months is shown in Table 2. Using a diode laser, 66.6% and 73.3% of the sites on distal and mesial sides, respectively, at 6 months showed the complete papilla fill [Table 3]. However, no difference was found in all the parameters when I-shaped incision and diode laser were compared.

Inter-implant papilla (implant papilla) forms in between two adjacent implants when horizontal distance between the two adjacent implants is ≥3 mm and vertical distance from CP to the crest of the bone between adjacent implants is 3 mm. Gastaldo et al. in 2004[24] and Choquet et al. in 2001[15] described the effect of both horizontal and vertical distance between adjacent implants on the incidence of interproximal papilla. Studies have reported that when the vertical distance between 2 implants is 3 mm, 80% of the time complete papilla fill occurs. In the present study, only the vertical distance between the crest of the bone and CP was used to assess the papillary fill. In the present study, we had three sites where two implants were placed; among these three sites, it was seen that complete papilla fill was seen in the site with which diode Laser was used. Grossberg in 2001 found that 4 of 12 patients showed complete papilla fill between implants.[25] Lee et al. in 2005 found that ST height between two adjacent implants was 3.3 ± 0.5 mm.[26] Shahidi et al in 2008 compared the mid crestal incision and modified flap technique for second stage implant surgery. They found the papilla height to be 3.44 mm in the modified flap technique versus 2.66 mm when mid crestal incision was given. Similarly, the present study reported the ST height in between the implants in the Groups I and III [Graph 1].

Graph 1

Bar chart representing site of implant placement

Peri-implant mucosa level is said to be influenced by the biologic width around implants and the periodontal biotype. In the present study, we have considered gingival biotype, which was categorized as thick and thin. Gingival biotype influences facial marginal gingival levels rather than interproximal papillary level adjacent to dental implants. Nisapakultorn et al. in 2010[27] and Souza et al. in 2012[28] reported that peri-implant biotype does not influence the peri-implant papilla fill but has an influence on the peri-implant marginal mucosa. A thin biotype is said to lead to increased risk of recession. In the present study too, gingival biotype did not seem to influence the papilla fill or changes in crestal bone level at any time period, as in other studies.

In the present study, the number of implants included was less, which did not allow for comparison among the three techniques used for second-stage implant surgery. The parameters were evaluated after a short follow-up period of 6 months after placement of super structure.

CONCLUSION

Within the limitations of the present study, it can be concluded that diode laser when used during second-stage surgery will bring about maximum papillary fill and minimal crestal bone loss when compared to I-shaped incision and midcrestal incision.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.