Comparison of clinical efficacy of diode laser and erbium, chromium: Yttrium, scandium, gallium, and garnet for implant stage 2 recovery procedure - A randomized control clinical study.

AIM: The aim is to compare the clinical efficacy of diode laser and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) laser for implant stage 2 recovery procedure.
MATERIALS AND METHODS: A total of 30 patients who had undergone dental implant placement were included in this study. The subjects were randomly allocated into three groups. Group 1 patients (n = 10) had implant recovery using diode laser, Group 2 (n = 10) implant recovery with Er, Cr:YSGG and conventional scalpel method (n = 10) was the third group. The pain assessment was recorded using visual analog scale (VAS scale), time taken for the procedure, intra-operative bleeding, time taken for healing were recorded for the three groups.
RESULTS: Data were tabulated and the results were analyzed using SPSS software version 26. Mann-Whitney U-test was used to compare the postoperative analgesic used, postoperative VAS score, the time taken for recovery and time taken for healing between the three study groups. Results were considered to be statistically significant when P < 0.05. Operation duration under Er, Cr:YSGG were much faster than the diode laser, however the results were not statistically significant (P = 0.051). The operation time under Er, Ch: YSGG and laser were faster than the conventional scalpel group (P = 0.000). The time taken for healing was faster in the Er, Cr:YSGG laser group than the diode laser and the scalpel group (P = 0.000). VAS scale at day 0 was higher in the conventional group than the two laser groups (P = 0.000).
CONCLUSION: Considering the advantages of both these laser systems such as less anesthesia, less surgical trauma and faster healing, and post-operative comfort, lasers are an effective tool for implant stage two recovery techniques. However, since diode lasers are more cost effective when compared to Er, Cr:YSGG, diode lasers may meet the clinical needs when compared to hard-tissue lasers. Copyright:

INTRODUCTION

Implants when placed in the oral cavity can follow one-stage or two-stage protocol.[1] In one-stage protocol, implants are placed along with healing abutment, known as the “submerged” or “delayed” approach. The two-stage implant placement was the original Brånemark et al. procedure and was advocated by this pioneer as a way of promoting stress-free integration of implants within the mandible.[2] The implant was inserted in a first surgery and submerged for three to 6 months to permit osseointegration. In a second surgical procedure, the implant is exposed, its cover screw removed, and the implant was then fitted with an abutment and the prosthetic phase of treatment was completed.

Lasers in the field of dentistry have been used for a plethora of treatments involving the hard tissues and soft tissues.[3] There are two types of lasers used in dentistry, soft-tissue dental lasers that have been cleared by the Food and Drug Administration include carbon dioxide lasers (CO2), argon lasers, diode lasers, and hard-tissue lasers which include the neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers, Ho:YAG lasers, and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) lasers.[34] Lasers have been used for periodontal procedures, for endodontic canal disinfection during root canal treatment, for the preparation of cavities and for excision of minor soft-tissue lesions in the oral cavity.[5] Lasers largely decrease the pain as compared with the conventional treatment options available.[6]

Lasers have been used widely in implant dentistry for placing incision, debridement of an infection before implant placement, disinfection of the sockets in immediate implant placement, implant surface decontamination, and for the stage two recovery of implant.[4] Advantages of lasers are that there is potentially a decreased need for sutures with no bleeding and reduced need of anesthesia.[7] The chance for microbial infections is lower due to its bactericidal effect. The increased postoperative comfort provided to the patient makes lasers an effective alternative treatment to the conventional scalpel techniques.

The critical factor to be considered when lasers are used in oral Implantology is the peri–implant bone temperature. Eriksson and Alberktsson concluded that a temperature rise over 47°C for 1 min can cause irreversible bone damage which can affect osseointegration.[5] Lasers such as carbon dioxide and Nd:YAG have been shown to cause structural damage to both the implants and peri implant bone.[8] However, both Er:YAG and Er, Cr:YSGG lasers have been used successfully in various implant surgical procedures without affecting osseointegration. Kreisler et al. compared the effects of different laser systems on dental implant surfaces and reported that Er:YAG and gallium-aluminum-arsenide diode lasers does not produce excessive heat in the peri-implant tissue, hence can be used safely.[9]

The use of diode lasers for implant stage 2 recovery procedures has been studied by several authors.[9101112] Er, Cr:YSGG laser system is highly versatile which enables the treatment of both hard (enamel, dentin, bone) and soft tissues. They also have excellent tissue ablative properties and can aid in faster healing due to minimal tissue trauma.[13] The aim of the study is to compare the clinical efficacy of diode laser (940 nm) and Er, Cr:YSGG (2780 nm) laser with conventional scalpel procedure for implant stage two recovery.

MATERIALS AND METHODS

This randomized control clinical study was carried out on patients who received dental implant placement at Department of Implantology, from the period May 2018 to May 2019. The study was reviewed and approved by the institutional review board (Ethical clearance number-IHEC/SDC/IMPLANT-1504/19/01). All patients were informed on the nature of the study and written informed consent was obtained from those showed willingness toward the study. All implants placed were of the same brand (Nobel Biocare.) Patients affected by severe systemic diseases, uncompensated diabetes or uncontrolled periodontal disease, and those smoking >10 cigarettes daily, were excluded from the study. Patients who had reduced keratinized gingiva, those with thin gingival biotype were excluded from the study. Patients who had peri-implant bone loss in the peri-apical radiograph were also excluded from the study.

Following preoperative assessment a total of 30 systemically healthy patients who had undergone mandibular posterior teeth implant placement were included in this study. The randomization method used was random chit method of allocation of the patients into the three different groups and sample size calculation was done with 80% power and 95% confidence interval. Patients were age and gender matched, the study included patients in the age group of 25–45 years. Implants in the first group (n = 10) were uncovered with soft-tissue laser (diode laser). Implants in the second group (n = 10) were uncovered with hard-tissue laser (Er, Cr:YSGG laser). Implants in the third group (n = 10) were uncovered with conventional scalpel method. Minimal institutional charge for the laser treatment was paid by the patients undergoing procedure.

The stage two recovery procedure for Group I patients were done using 940 nm wavelength diode laser (Ezlase 940; Biolase Technology, Inc., Irvine, CA) according to the guidelines recommended by the manufacturer (surgical E4 400 μm tip, 2.5 W power, average power: 1.25 W, pulse length CP2: 1.00 ms, pulse interval: 1.00 ms, duty cycle 50½, pulsative mode). In Group 2, implants were uncovered using the Er:YAG laser with the following fixed operation parameters: 300 mJ, 18 Hz, water cooling at 40%, energy density per pulse: 38.21 J/cm2, tip size: 1.0 mm × 17 mm, distance: 2 mm, tip angle set at 70°, no anesthesia. For implant recovery, laser-assisted incisions were expanded in a circular fashion, starting from the most likely position of the implant's closure screw in both the laser groups. In Group 3, patients following administration of 1:100000 lignocaine with adrenaline, a full-thickness muco-periosteal flap was raised and granulation tissue was removed using a plastic curette. The cover screw was replaced with respective healing abutments and the flaps were approximated using 3-0 black silk with simple interrupted sutures.

The postoperative instructions were given and the patients were advised to use paracetamol (500 mg) as an analgesic only when required. They were instructed to take a maximum of three tablets per day in case of persisting pain. The time taken for the procedure was noted with a stop clock. The total operation time was divided by the number of implants, and the mean operation time per implant was recorded. Immediately, after the procedure, the pain perception from the patient was noted using visual analog scale (VAS) values ranging from 0 to 10. Patients were recalled on every alternate day for a period of 10 days to assess the postoperative edema and soft-tissue inflammation. Time duration taken for healing following stage two recovery was also assessed in the study participants on regular recall visits.

RESULTS

A total of 30 patients participated in this study and they were treated alike except for the recovery technique followed. Each group was allocated 10 patients. In all the three groups there were 6 male and 4 female patients. A total of 16 implants were uncovered in Group 1 (diode laser), 18 implants in Group 2 (hard tissue laser), and 18 implants in Group 3 (conventional scalpel method). Data were tabulated and the results were analyzed using SPSS (Statistical Package for Social Sciences) Version 26.0 statistical Analysis Software. (IBM, Chicago, United States of America). The descriptive statistics of the three groups is shown in Table 1. Mann–Whitney U-test was used to compare the postoperative analgesic used, postoperative VAS score, the time taken for recovery and time taken for healing between the three study groups. Results were considered to be statistically significant when P < 0.05.

Table 1

Descrıptıve statıstıcs of the study groups

Parameters	Group 1 (diode laser) (n=10)	Group 2 (Er, Cr:YSGG) (n=10)	Group 3 (scalpel) (n=10)
Age (years) (mean±SD)	37±7	36±7	35±7
Gender
Male	6	6	6
Female	4	4	4
Number of implants recovery done	16	18	18
LA used (ml), mean±SD	0.00	0.22±0.428	1.39±0.608
VAS scale (day 0)	0.25±0.447	0.28±0.461	1.44±1.042
Time taken for recovery (min), mean±SD	13.6±4.4	8.3±4.8	19.8±5.9
Intra operative bleeding, mean±SD	0.44±0.629	0.61±0.850	2.111±0.900
1 - No bleeding	8	6	-
1 - Minimal	6	10	4
2 - Normal	2	2	14
3 - Excessive bledding	-	-	-
Time taken for healing (number of days)	4.5±0.632	3.22±0.428	8.5±1.618
Postoperative edema/soft-tissue inflammation on the 3rd day	0.00	0.00	0.61±0.608
Total number of analgesics used	0.19±0.403	0.67±1.283	3.06±0.938

SD – Standard deviation; VAS – Visual analog scale; LA – Local anaesthesia; Er, Cr:YSGG – Erbium, chromium- doped yttrium, scandium, gallium, and garnet; n – number of patients

Operation duration under Er, Cr:YSGG were much faster than the diode laser, however the results were not statistically significant (P = 0.051). The operation time under Er, Cr:YSGG and diode laser were faster when compared with the conventional scalpel group (P = 0.00) [Tables 2–4 and Figure 1]. Immediately, after the procedure, the patient was shown the VAS scale and was asked about the amount of pain and the values were noted down. VAS scale at day 0 was higher in the conventional group than the two laser groups (P = 0.000). The VAS score between the two laser groups did not show any significant difference (P = 0.993). The intra-operative bleeding was less in the diode laser group when compared with Groups 2 and 3 [Table 1]. There was no statistically significant difference in the intra operative bleeding between the diode laser and Er, Cr:YSGG laser group (P = 0.807), however when compared with the conventional scalpel group, the results were statistically significant (P = 0.000) [Tables 2–4 and Figure 2].

Table 2

Comparison of clinical parameters between the Group 1 and Group 2

Outcome	Groups	Mann-Whitney U-test value	P
Time taken for recovery	Group 1 (Diode laser)	11.00	0.001**
	Group 2 (Er, Cr:YSGG)
Time taken for healing	Group 1 (Diode laser)	23.00	0.001**
	Group 2 (Er, Cr:YSGG)
Intraoperative bleeding	Group 1 (Diode laser)	133.50	0.67
	Group 2 (Er, Cr:YSGG)
Analgesics	Group 1 (Diode laser)	133.00	0.59
	Group 2 (Er, Cr:YSGG)
LA	Group 1 (Diode laser)	112.00	0.04*
	Group 2 (Er, Cr:YSGG)
VAS 0	Group 1 (Diode laser)	140.00	0.85
	Group 2 (Er, Cr:YSGG)

P value < 0.05 should be statistically significant. VAS – Visual analog scale; LA – Local anesthesia; Er, Cr:YSGG – Erbium, chromium- doped yttrium, scandium, gallium, and garnet; *P value less than 0.05 as statistically significant; **P value less than 0.01 as highly statistically significant

Table 4

Comparison of clinical parameters between the Group 1 and Group 3

Outcome	Groups	Mann-Whitney U-test value	P
Time taken for recovery	Group 1 (Diode laser)	84.50	0.03*
	Group 3 (Scalpel)
Time taken for healing	Group 1 (Diode laser)	0.001	0.001**
	Group 3 (Scalpel)
Intraoperative bleeding	Group 1 (Diode laser)	25.00	0.001**
	Group 3 (Scalpel)
Analgesics	Group 1 (Diode laser)	9.50	0.001**
	Group 3 (Scalpel)
LA	Group 1 (Diode laser)	8.00	0.001**
	Group 3 (Scalpel)
VAS 0	Group 1 (Diode laser)	50.00	0.001**
	Group 3 (Scalpel)

P<0.05 was considered statistically significant. VAS – Visual analog scale; LA – Local anesthesia. *P < 0.05 – Statistically significant; **P < 0.01 – Highly statistically significant

Figure 1

Comparison of the time taken for the recovery procedure between the study groups

Figure 2

Comparison of the intra-operative bleeding between the study groups

The amount of local anesthesia (ml) used during the implant recovery procedure was more in the Group 3 when compared to Group 2 and Group 1 [Table 1]. The results were statistically significant [Tables 2–4]. Postoperative analgesics used were highest in the conventional scalpel method and least when lasers were used (P = 0.000) [Table 2]. Postoperative complications were seen only in the conventional scalpel method. Postoperative edema and inflammation was noted on the 3rd day after the procedure and was only evident in the Group 3 and the mean ± SD was 0.61 ± 0.608 [Table 1]. Time taken for healing/impression making was recorded in days and the impressions were taken as early as the 4th day in Group 1 followed by Group 2 and in Group 3 between 8 and 10 days [Table 1]. The time taken for healing was faster in the Er, Cr:YSGG laser group than the diode laser and the scalpel group (P = 0.000) [Tables 2–4 and Figure 3].

Figure 3

Comparison of the time taken for the peri-implant soft-tissue healing between the study groups

When comparing the VAS scored between day 0 and at day 3, there was a significant difference in the VAS score at day 3 between the conventional scalpel group and the two laser groups [Figure 4].

Figure 4

Comparison of vas score at day 0 and at day 3 between the study groups. VAS – visual analog scale

DISCUSSION

Various laser systems have been studied for their efficacy on the implant surfaces. Romanos et al. on evaluating Nd:YAG laser on three titanium discs observed severe damage, porosity, fusion, microfracture, and cratering even at minimum power settings.[14] Park et al. did a similar study from which the authors suggested that Nd:YAG laser was not adviced, but the CO2 lasers with controlled power settings between 1.0W and 2.0W did not seem to induce morphological changes in surfaces studied.[15] Oyster et al. studied the thermal changes of the CO2 laser on titanium implants placed in the pig mandibular bone and concluded that there was not damage on the study surfaces but there was temperature increase of about 50°C in the peri implant bone and the lasers were not able to remove the blood and saliva from the previously contaminated surfaces even at maximum power settings.[16] Both Er:YAG and diode lasers did not cause surface alterations on titanium implant surfaces even when used at higher power settings.[17]

The stage 2 implant recovery can be done using a scalpel, electrocautery, or lasers. When electrocautery is used there is a higher chance of damaging the surface of the implant which might affect the osseointegration and leading to implant failure. The current study had compared the efficacy of two different laser systems with different wavelengths for implant Stage 2 recovery procedures. Several studies have proven that diode lasers do not impair the implant surface; however, more frequent resting periods are required when operating in contact mode with diode lasers.[1018] This may prevent more than a 10 degree temperature rise, thus not altering the clinical parameters. The cooling requirement during the use of Er, Cr:YSGG laser offers an advantage in having positive effects on the soft tissue healing around implants. In the present study, the time taken for healing was faster in the Er, Cr:YSGG group than the other two groups (P = 0.000). This could be attributed to the cooling system used in the Er, Cr:YSGG lasers resulting in minimal tissue trauma and lesser postoperative complications when compared with the diode lasers.

In the study done by Tunc et al., using the diode and Er, Cr:YSGG laser systems for implant recovery, the VAS was noticed to be increased as the time taken for the procedure was increased.[19] In the current study, the VAS scale was higher in the conventional group than the two laser groups (P = 0.000), however the VAS score between the two laser groups did not show any statistically significant difference.

Lasers have let to reduction in the use of anesthesia and also the postoperative use of analgesics in addition to have accelerated the wound healing.[20] In the present study, the amount of postoperative analgesics used in the laser group was lesser as compared with the scalpel group. Eroglu et al. suggested that there was no statistically significant difference in the postoperative analgesics used between the Er, Cr:YSGG and the scalpel group.[21] Similar to the study by Tunc et al., in the current study there was not any statistically significant difference between the laser groups with respect to the use of postoperative analgesics.[19]

Few studies comparing the laser and the conventional scalpel had shown reduction in the postoperative pain and swelling using lasers.[222324] Thus, the procedure with lasers is more comfortable for both the clinician and the patient. The efficacy of different lasers depends on the depth of penetration to the underlying tissues. Lasers such as CO2, Er:YAG and Er, Cr:YSGG, the laser light is absorbed by the superficial layers and hence is advantageous for rapid vaporization of the soft tissues. However, lasers such as diode and Nd:YAG have deeply tissue penetrating ability, thus have greater thermal effects and thicker coagulation area on the treated surface. The Er, Cr:YSGG laser is to be less effective on preventing bleeding when compared with the diode laser.[252627] However in the present study, there was no significant difference in the hemostatic activity between the two laser groups. Thus, our findings suggest that the Er, Cr:YSGG laser does not present a high risk of bleeding complications when used for soft tissue surgeries. The main advantage of using lasers in stage two recovery procedures is the unnecessity to suture, which could save the clinical operatory time. Operation duration under Er, Cr:YSGG were much faster than the diode laser, however the results were not statistically significant (P = 0.051). The operation time under Er, Cr:YSGG and diode laser were faster when compared with the conventional scalpel group (P = 0.00).

The cases represented in this study took into consideration the adequate keratinized gingiva before the start of the procedure. Care was taken to avoid patients who had thin gingival biotype and also those who required additional soft-tissue augmentation procedure during implant recovery. Thus from the above findings, we can conclude that Er, Cr:YSGG laser resulted in faster healing and lesser waiting time for making the prosthetic impressions when compared to the diode laser and conventional scalpel group. The added benefit of using Er, Cr:YSGG than diode laser is that, the bone over the closure screw in cases of subcrestal implants can be removed with minima tissue trauma during the second-stage surgery. The post-operative discomfort for the patient was highly reduced, with minimal bleeding and also increased operator visibility in both the laser groups than the conventional scalpel method.

CONCLUSION

Within the limitation of the present study, the use of lasers was more advantageous than the scalpel method for Stage 2 recovery of implants. Diode lasers are more economical and easily available, smaller and can meet the needs of the patients and the dentists when compared with hard tissue lasers. Thus, both diode and Er, Cr:YSGG lasers can be preferred and used in regular practice pertaining to the implant dentistry due to faster healing and lesser shrinkage, prosthetic impressions can be taken earlier than with the conventional scalpel procedure.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Table 3

Comparison of clinical parameters between the Group 2 and Group 3

Outcome	Groups	Mann-Whitney U-test value	P
Time taken for recovery	Group 2 (Er, Cr:YSGG)	0.001	0.001**
	Group 3 (Scalpel)
Time taken for healing	Group 2 (Er, Cr:YSGG)	0.001	0.001**
	GROUP 3 (Scalpel)
Intraoperative bleeding	Group 2 (Er, Cr:YSGG)	43.00	0.001**
	Group 3 (Scalpel)
Analgesics	Group 2 (Er, Cr:YSGG)	37.00	0.001**
	Group 3 (Scalpel)
LA	Group 2 (Er, Cr:YSGG)	29.00	0.001**
	Group 3 (Scalpel)
VAS 0	Group 2 (Er, Cr:YSGG)	58.50	0.001**
	Group 3 (Scalpel)

P<0.05 was considered statistically significant. VAS – Visual analog scale; LA – Local anaesthesia; Er, Cr:YSGG – Erbium, chromium - doped yttrium, scandium, gallium, and garnet; *P < 0.01 – Highly statistically significant