A COMPARATIVE EVALUATION OF LASER ASSISTED & CONVENTIONAL OPEN FLAP SURGICAL DEBRIDEMENT PROCEDURE IN PATIENTS WITH CHRONIC PERIODONTITIS – A CLINICAL AND MICROBIOLOGICAL STUDY- A PILOT PROJECT

A COMPARATIVE EVALUATION OF LASER ASSISTED & CONVENTIONAL OPEN FLAP SURGICAL DEBRIDEMENT PROCEDURE IN PATIENTS WITH CHRONIC PERIODONTITIS – A CLINICAL AND MICROBIOLOGICAL STUDY- A PILOT PROJECT

Shreya Shetty ^{* 1}, Karunakar Shetty ¹, Saad Alghamdi ¹, Nouf Almehmadi ¹ and Tanya Mukherjee ²

Dentistry Program ¹, IBN Sina National College of Medical Sciences, Jeddah, KSA.

Government Hospital ², Kakching - 795103, Manipur, India.

ABSTRACT: Background and Objectives: Current research suggests several advantages of the adjunctive use of lasers in periodontal therapy. The aim of this study was to assess and evaluate the comparative therapeutic effects of laser-assisted and conventional open flap debridement procedures. Materials and Methods: 30 sites in 15 patients (9 males and 6 females), age range (25-50 yrs) with chronic periodontitis having probing depth ≥5 mm after phase I therapy were randomly assigned to test group (laser-assisted flap debridement) & control group (conventional open flap debridement) in a split-mouth design. Clinical and microbial parameters were analyzed at baseline, 3 months, and 6 months. In addition, Soft tissue healing was also assessed using the healing index at 1 week, 2 weeks, 1 month, 3 months & 6 months. Results: The change in clinical parameters in the test and control groups was not statistically significant at the various time intervals (p˂0.05). However, the microbiological analysis showed a significant reduction in the CFU counts of periodontal pathogens in the test sites when compared to the control sites at immediate post-op and 6 months (p>0.05). Conclusion: Laser assisted flap procedures showed better therapeutic outcomes when compared to the conventional open flap debridement with respect to microbial parameters; however, future long term RCTs (randomized clinical trials) with larger sample sizes need to be carried out to ascertain their benefits.

Laser-assisted flap surgery, Conventional flap surgery, Healing, Bacterial pathogens, Original research

INTRODUCTION: Periodontitis is the result of complex interrelationships between infectious agents such as bacteria and host factors. It is universally accepted that periodontal disease is the result of mixed bacterial infections that require the participation of a very limited number of the members of the anaerobic microbiota inhabiting the subgingival region, and results in the destruction of the supporting structures of the teeth ^{1, 2}.

Most conventional methods used to treat the disease involve disruption of the biofilm by the mechanical removal of subgingival plaque and, sometimes, the adjuvant use of antimicrobial agents and mechanical surgical debridement of pocket and root surfaces damaged as a result of periodontal disease. An alternative (ecological) approach would be to alter the environment of the pocket to prevent the growth of the putative pathogens, as suggested by Marsh (ecological plaque hypothesis) ³.

Nonsurgical therapy leads to resolution of inflammation, reduction in bacterial load, and reduction in probing pocket depth. However, the complete removal of bacterial toxins from the root surfaces in the deep periodontal pockets is not always achieved with nonsurgical therapy ⁴. 

Instrumentation is not possible in inaccessible areas such as furcation, grooves and concavities ⁴. In addition, it has also been suggested that sonic and ultrasonic instrumentation does not result in the killing of periodontopathogens ⁵. These instruments merely help to reduce the bacterial load by the mechanical removal of plaque and calculus.

Surgical therapy performed in cases with persistent inflammation, deep pockets, class II and III furcation defects, and intrabony defects provides better accessibility to root surfaces as well as osseous defects. However, periodontopathogens persist in the mixed-species plaque biofilm on tooth surfaces, adhere to and enter the epithelial cells, and are tissue invasive in nature ⁶. These are the major sources for re-colonization and reinfection. Therefore, the above methods may prove ineffective unless supplemented by concomitant use of systemic antibiotics, which again have their own share of adverse effects.

LASERS - an acronym for Light Amplification by Stimulated Emission of Radiation; have been used in periodontology to reduce periodontopathogenic bacteria, ^{7, 8, 9} remove the pocket epithelium, and retard epithelial migration into the pocket. If the wavelength is appropriate, it is also possible to remove the hard deposits (i.e., calculus) and to perform root planning ¹⁰. A significant reduction of periodontopathogenic bacteria has also been demonstrated, regardless of laser wavelength ^{7, 11, 12}.

Diode laser with a wavelength of 810 nm or 910–980 nm, does not interact with dental hard tissues and therefore, is an excellent soft tissue surgical laser, indicated for cutting and coagulating gingiva and oral mucosa, and for soft tissue curettage or sulcular debridement with an additional bactericidal effect ¹¹.

The principal goal of periodontal therapy is the elimination of bacterial plaque and also prevention of its accumulation. Conventional open flap surgery in conjunction with mechanical debridement has been shown to effectively achieve this goal. However, incomplete removal of pathogens from the base of deep pockets & tissue penetrating organisms along with other inherent drawbacks such as lack of hemostasis, intraoperative and postoperative pain & discomfort with this technique have led to the popularity of laser-assisted procedures ¹³ which have claimed to overcome the above shortcomings and effectively achieve the goal of plaque elimination by completely sterilizing the periodontal pocket.

The purpose of this study was, therefore, to comparatively assess and evaluate clinically and microbiologically the treatment outcomes following laser-assisted and conventional open flap surgical procedures.

MATERIALS AND METHODS: Following an initial screening, 15 patients (9 males and 6 females) with chronic periodontitis involving two or more quadrants in the mouth were selected from the outpatient department of a dental institute for the study based on the following criteria:

Inclusion Criteria:

1. Patients willing to sign on a written consent form.
2. Male and female patients aged between 25-50 years.
3. Patients with suprabony pockets with probing pocket depth ≥ 5mm in 1 or more teeth in two or more quadrants evidenced clinically and radiographically.
4. Number of teeth present ≥ 20.

Exclusion Criteria:

1. Presence of any systemic or debilitating diseases.
2. Pregnant or lactating women.
3. A recent history or presence of any acute or chronic infections.
4. Patients with history of any drug intake including antibiotics, analgesics or any other drugs three months prior to study.
5. Patients who have undergone periodontal therapy in the last six months.
6. Patients who are smokers/paan/tobacco/ betelnut users.
7. Patients who are physically or mentally challenged.

After obtaining the required permissions and consent from the institutional Ethical Committee, (IEC NO - VEF/14112013), the selected patients were randomly divided into two groups following the split-mouth/arch study design thereby comprising of 15 patients in each group- Test (n=15) & Control (n =15).

The following clinical parameters where recorded at baseline, 3 months & 6 months in both the groups:

1. Gingival index (GI) by Loe and Sillness (1963) ^14.
2. Plaque index (PI) by Turesky-Gilmore-Glickman modification of the Quigley Hein Plaque index (1970).
3. Probing pocket depth (PPD).
4. Relative attachment level (RAL) (using an acrylic stent).
5. Soft tissue healing using healing index ¹⁵ was assessed at day 1, 1 week, 2 weeks, 1 month, 3 month, and 6 months following therapy.

Treatment Procedure: All periodontal surgical procedures were performed on an outpatient basis under aseptic conditions. Standardized surgical procedures for the test and control sites were performed as follows

The surgical area was anesthetized using local anesthetic 2% lignocaine with adrenaline 1:80,000 (Lignox 2%)^α. Intracrevicular incisions were made and full-thickness mucoperiosteal flaps were elevated, granulation tissue was collected in an Eppendorf tube, and refrigerated at- 20 °C till microbial analysis was performed. Following flap reflection, the hard tissue deposits were debrided using an ultrasonic scaler and Gracey curettes.

In the test sites, granulation tissue debridement using soft tissue diode (980nm) laser*  was done by lasing the tissue for 3 min at 2.5 watts, and at the end of all possible debridement, the residual granulation tissue was collected and stored in a seperate Eppendorf tube till microbial analysis was performed. In the control sites, following flap reflection, the granulation tissue and hard tissue deposits were debrided using an ultrasonic scaler and Gracey curettes. At the end of all the possible debridement, the residual granulation tissue was collected and stored in another separate Eppendorf tube for microbial analysis.

In both the sites, surgical flaps were repositioned to the presurgical level and sutured with 3-0 silk suture utilizing an interdental, direct suturing technique achieving primary closure. No periodontal dressing was given as healing had to be assessed.

One week following surgery, sutures were removed, and the area was irrigated thoroughly with saline. Recall appointments were made at the scheduled time intervals, as mentioned earlier, and at each visit, clinical parameters were recorded, oral hygiene instructions were reinforced, and scaling was done whenever necessary.

The granulation tissue collected and stored in the Eppendorf tubes, and the plaque samples were sent for microbial culture (anerobic) in both test and control groups at said time intervals.

Statistical Analysis: The clinical and microbiological parameters in both the groups were statistically analyzed by Student’s ‘t’ test using SPSS V13 software. Paired ‘t’ tests were used to compare the intragroup and intergroup variations. A ‘p’ value of 0.05 or less was considered significant.

RESULTS: A significant improvement in clinical parameters viz, gingival index, plaque index, probing pocket depth and relative attachment level within both the test and control groups at all the time intervals throughout the study was observed (p˂0.001) Table 1A and B. However, the difference between the 2 groups was not statistically significant (p≥0.05) Table 1C. Similarly, the healing index scores showed significant changes within both groups (p<0.001) in Table 2A and 2B but did not show any significant differences between the groups (p>0.05) Table 2C.

The assessment of the microbial parameters, viz., P. gingivalis, P. intermedia, and A. comitans CFU counts showed statistically significant changes (p˂0.001) within both the groups Table 3A and B. However, a significant reduction in the CFU counts of periodontal pathogens were found in the test group when compared to the control group at immediate post-op and 6 months (p˂0.001) but not at the other time intervals (p≥0.05) Table 3C.

TABLE 1: COMPARISON OF CLINICAL PARAMETERS (GINGIVAL INDEX, PLAQUE INDEX, PROBING POCKET DEPTH AND ATTACHMENT LEVEL)

A. TEST GROUP

B. CONTROL GROUP

C. INTER-GROUP COMPARISON

TABLE 2: COMPARISON OF HEALING INDEX BETWEEN THE TWO GROUPS FOR DIFFERENT TIME INTERVALS

TABLE 3: COMPARISON OF MICROBIOLOGIC PARAMETERS

A. TEST GROUP

B. CONTROL GROUP

C. INTER-GROUP COMPARISON

DISCUSSION: Successful periodontal therapy depends on anti-infective procedures aimed at eliminating or suppressing pathogenic organisms found in dental plaque associated with the tooth surface and within other niches in the oral cavity. Laser-assisted periodontal therapy has attracted attention recently as a potential alternative or adjunct to conventional mechanical debridement ^16-18. Carbon dioxide (CO₂) laser, neodymium-doped: yttrium-aluminum-garnet (Nd:YAG) laser, and diode and erbium-doped: yttrium-aluminum-garnet (Er:YAG) laser have been used in the therapy of periodontal pocket for hard tissue as well as soft tissue management ^{7, 10}.

It has been suggested that a part of the laser energy scatters and penetrates during irradiation into periodontal pockets. The attenuated laser at a low energy level might then stimulate the cells of surrounding tissue resulting in a reduction of the inflammatory conditions, in cell proliferation, and an increased flow of lymph, improving the periodontal tissue attachment and possibly reducing postoperative pain ^19-21.

Soft tissue lasers such as diode and Nd: YAG have the potential for curettage of the pocket wall and disinfection of periodontal pockets ^{16, 17}. A search of literature reviews revealed very few reports of the use of CO₂ and Er:-YAG lasers in surgical pocket therapy. To the knowledge of the authors, there are few reports of the use of diode laser as an adjunct to mechanical debridement in access flap surgery, although it is the most commonly used laser ^{16, 17, 22,} and some provide mixed reports ²³. Most reports focus on the use of laser for non-surgical periodontal therapy ^{21, 24}.

In the present study, it was therefore decided to evaluate the adjunctive effects of a soft tissue diode laser in open flap debridement on the clinical and microbiological parameters.

Systemically, healthy patients with chronic periodontitis and presenting pockets on contralateral sites were recruited in this split-mouth designed study and randomly assigned to test and control groups to avoid bias. The clinical study was designed to compare the clinical treatment outcomes of laser-assisted flap debridement and conventional open flap procedures. A split-mouth design was used as this excludes the influence of individual patient characteristics and helps to obtain a more powerful estimate of treatment effect with a smaller sample size ²⁵. The sample size in this study was arrived at on consultation with the statistician, which was in accordance with a vast majority of clinical periodontal studies carried out in humans ²⁶. The gold standard for recording changes in periodontal status is the longitudinal measurements with clinical attachment level (CAL) from CEJ to the base of the pocket.

Due to the relative inconsistencies in determining CEJ accurately at the selected sites, it was decided to use a customized acrylic stent and use the base of the stent as the fixed reference point and evaluate relative attachment level (RAL) and PPD.

To evaluate the antibacterial effect of lasers, it was decided to assess the debrided tissues and the plaque samples at regular intervals post- opera-tively by anaerobic culture. This was essentially carried out to ascertain whether reduced microbial counts enhanced clinical outcomes.

There was a significant improvement in clinical parameters (gingival index, plaque index and probing pocket depth and attachment levels) within both, the laser and conventional open flap treated groups from baseline to 3 months and up to 6 months which is line with various evidence ^{16, 17, 22} concluding similar findings.

On the contrary, no significant differences were observed at the various time intervals between the laser-assisted open flap debridement and open flap debridement procedure in accordance with Gokhale et al., 2012 ²² who also observed similar findings.

Interestingly, significant improvement in healing within both the laser-assisted open flap debridement & open flap debridement procedure was observed in this study, as evidenced by the healing index scores, thus suggesting that both the procedures lead to effective healing outcomes ^27-29. Additionally, healing outcomes may be better with laser because of enhanced reduction in inflammatory mediators ³⁰.

However, no significant differences were observed at the various time intervals between the laser-assisted open flap debridement surgery versus open flap surgery. This was in accordance with some evidence ^{31, 32,} and in contrast to the findings of Grzech et al., ³³ and Kripal et al., ³⁴ who reported delayed healing_.

Although the reliability and reproducibility of the index used for assessing healing in this study is not aptly justified, there is convincing evidence suggesting this index has been reliable to evaluate clinical soft tissue healing in periodontal studies ³⁵.

The soft tissue diode laser has been widely suggested to be safe to use as it does not react or adversely affect the dental hard tissues i.e. the tooth as well as the root surfaces ^{31, 34, 36}. In the present study, too, no untoward effects were reported.

With regard to the microbiological parameters, open flap debridement procedures have also shown to significantly reduce microbial counts of periodontal pathogens ^{37, 38,} which was also observed in our study. Similarly, there was also a significant reduction in CFU counts of P. gingivalis, P. intermedia & A. actinomycetem- comitans within the laser-assisted open flap debridement group at the various time intervals. This is in accordance with the findings of various investigators ^39-41 wherein; they observed that a laser facilitates bacterial elimination from periodontal pockets, resulting in better healing.

An interesting finding in this study was a significantly greater reduction in the CFU counts of P. gingivalis, P. Intermedia & A. Actino-mycetemcomitans, observed in the laser assisted open flap debridement compared to the open flap debridement procedure at immediate post-op and 6 months time intervals. This is in accordance with the findings of Gokhale SR et al., 2012 ²² where the greater reduction was found in CFU of obligate anaerobes in the laser group compared to the open flap debridement group. As concluded by various investigators, this could possibly be due to the direct cytopathic effects of the lasers on the periodontal pathogens ^{18, 41}. However, there were no significant differences observed in the various other time intervals, which was in accordance with the findings of Ren et al., ²¹ wherein they found no advantage was achieved with the additional use of laser.

CONCLUSION: Laser-assisted flap procedures have potentially better therapeutic outcomes when compared to the conventional open flap debridement, which is evident from the enhanced reduction in periodontal pathogens.

Limitations:

1. More sophisticated and sensitive healing assessment methods like fluorescein angiogram, flow cytometry using markers for various cells and cytokines, and also immunohistochemistry evaluation of healing using various MMPs as markers could also be done.
2. For more accurate microbiological assessment, an advanced diagnostic tool like PCR or ELISA kits could have been used, although they would have proved very expensive.
3. Larger sample size involving a larger cross-section of the population needs to be carried out.

ACKNOWLEDGEMENT: The services of Mr. Murthy, who performed the statistical analysis of the results of the study.

CONFLICTS OF INTEREST: The authors report no conflict of interest in this study.

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    How to cite this article:

    Shetty S, Shetty K, Alghamdi S, Almehmadi N and Mukherjee T: A comparative evaluation of laser assisted & conventional open flap surgical debridement procedure in patients with chronic periodontitis – a clinical and microbiological study- a pilot project. Int J Pharm Sci & Res 2020; 11(10): 4957-65. doi: 10.13040/IJPSR.0975-8232.11(10).4957-65.

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