Lasers in periodontal therapy

Clinical parameters in soft tissue adjunctive periodontal procedures for orthodontic patients: surgical laser vs scalpel -: A systematic review

OBJECTIVES

To systematically review existing literature regarding clinical parameters comparing surgical laser and conventional surgery with scalpel for soft tissue adjunctive periodontal procedures in orthodontic patients.

METHODS AND MATERIALS

MEDLINE, Scopus, Web of Science, The Cochrane Library, LILACS, Bibliografia Brasileira de Odontologia (Brazilian Dental Literature - BBO), Embase, Open Grey, Portal de Periódicos da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Coordination for the Improvement of Higher Education Personnel - CAPES), and Google Scholar were searched up to December 2020 without language restriction. Clinical trials comparing clinical parameters from surgical laser and conventional surgery with scalpel for soft tissue adjunctive periodontal procedures in orthodontic patients were selected. Risk of bias (RoB) assessments were performed using the Cochrane RoB2 tool. Narrative syntheses were performed, and the certainty of evidence was determined using the GRADE tool.

RESULTS

Five randomized clinical trials were included. One study was rated as low RoB, whereas others presented some concerns or high RoB. The studies were highly heterogeneous in relation to the procedure performed, laser protocol, outcomes evaluated, and follow-up periods. In general, regardless of the procedure and laser protocol used, the studies did not show significant differences between laser and scalpel for the outcomes of probing pocket depth, clinical crown length, gingival index, and relapse rate. Pain and bleeding were significantly lower with the use of laser compared with the scalpel. The certainty of evidence ranged from moderate to very low.

CONCLUSIONS

The existing literature on the subject is scarce and very heterogeneous and has methodological limitations. Based on the available evidence, it is not possible to draw definitive conclusions about the beneficial effect of laser use in orthodontic patients.

Ex Vivo Evaluation of Gingival Ablation with Various Laser Systems and Electroscalpel

Objective: The aim of this study was to perform a systematic and multifaceted comparison of thermal effects during soft tissue ablation with various lasers and an electroscalpel (ES). Materials and methods: Er:YAG, Er,Cr:YSGG, CO₂, Diode, Nd:YAG lasers (1 W, pulsed or continuous wave), an ES, and a scalpel (Sc; control), were employed for porcine gingival tissue ablation. Temperature changes during ablation were measured by using an infrared thermal imaging camera and a thermocouple. After ablations, the wounds were observed using stereomicroscopy and scanning electron microscopy (SEM), and histological sections were analyzed. Compositional analysis was also performed on ablated sites by SEM wavelength dispersive X-ray spectroscopy. Results: The surface temperature during irradiation was highest with CO₂ (over 500°C), followed by Diode (267°C) and Nd:YAG (258°C), Er:YAG (164°C), ES (135°C), and Er,Cr:YSGG (85°C). Carbonization was negligible (Er:YAG), slight (Er,Cr:YSGG), moderate (Nd:YAG and ES), and severe (CO₂ and Diode). Under SEM observation, Er:YAG and Er,Cr:YSGG showed smooth surfaces but other devices resulted in rough appearances. Histologically, the coagulated and thermally affected layer was extremely minimal (38 μm in thickness) and free from epithelial collapse for Er:YAG. Compared with other devices, less compositional surface change was detected with Er:YAG and Er,Cr:YSGG; additionally, the use of water spray further minimized thermal influence. Conclusions: Among various power devices, Er:YAG laser showed the most efficient and refined gingival ablation with minimal thermal influence on the surrounding tissues. Er:YAG and Er,Cr:YSGG lasers with water spray could be considered as minimally invasive power devices for soft tissue surgery.

Management of massive peripheral ossifying fibroma using diode laser

Peripheral ossifying fibroma (POF) represents a non-neoplastic, reactive lesion of gingiva. The precise etiopathogenesis of POF is unclear; however, it is suggested to originate from the connective tissue of periodontal ligament. This lesion predominantly occurs in the maxillary anterior region. The standard treatment protocol involves surgical excision followed by the biopsy of lesion. The reactive nature and unpredictable course attribute to a high recurrence rate of the lesion; hence, proper postoperative monitoring and follow-up of the lesion are necessary. The present case was surgically managed using diode laser and did not show any sign of recurrence during the follow-up period of 6 months. Minimum intraoperative bleeding and postoperative pain, ease of operation, and patient's acceptance enable laser-assisted growth excision as a better treatment modality to other conventional surgical procedures, thus offering diode laser as a viable and effective treatment alternative in the management of massive overgrowth.

Effective management of focal reactive gingival overgrowths by diode laser: A review and report of two cases

Background

Focal reactive gingival overgrowths (FRGO) are a common observation in a clinical dental practice that may occur in response to external and internal chronic stimuli in form of fibrous connective tissue lesions in the oral mucosa. Gingiva is the most commonly involved site of oral reactive lesions. For the confirmed diagnosis of FRGO not only clinical, but the histopathological presentation of the lesion plays a vital role. Various surgical treatment modalities like a scalpel, cryosurgery, electrosurgery, and lasers have been applied in the management of FRGO. The laser is new treatment modality being employed for treatment of FRGO.

Case report

The purpose of this paper is to attempt short review on FRGO with the management of FRGO using diode laser. Here, we present effective management of peripheral giant cell granuloma and peripheral ossifying fibroma using diode laser. The follow-up of 01year showed no recurrence in both the cases.

Conclusions

Diode soft tissue laser has added advantages like a bloodless surgical field, reduced bacteremia, minimal intra and postoperative discomfort over conventional modalities. Thus it is highly effective in the surgical management of FRGO.

Immediate laser-induced hemostasis in anticoagulated rats subjected to oral soft tissue surgery: a double-blind study

Given the growing trend towards medical indications for continuous use of anticoagulants, the number of patients on these medications continues to rise. The management of patients on oral anticoagulants requiring oral surgical procedures has aroused much controversy. Changes in an anticoagulation regimen are associated with an increased risk of thromboembolism. However, it seems logical and advantageous for the patients' health if surgery could be performed without any change to the anticoagulation therapy. In dentistry, high-power lasers have been poorly explored in this field. The hemostatic properties of high-power lasers could be helpful during oral soft tissue surgeries in anticoagulated patients. The aim of this study was to compare bleeding time in anticoagulated rats after lingual frenectomy performed with a scalpel or diode laser with bleeding time in healthy animals. Twenty-four male Wistar rats were assigned to four groups (n = 6): (CS) Control-Scalpel Surgery; (AS) Anticoagulated-Scalpel Surgery; (CL) Control-Laser (diode laser 810 nm/1.5 W) Surgery; and (AL) Anticoagulated-Laser Surgery (diode laser 810 nm/1.5 W). Warfarin administration was used to induce anticoagulation. Blood was blotted every 30 seconds with filter paper until bleeding stopped to verify bleeding time. Two blinded researchers performed the surgeries and collected the bleeding time data. Diode laser surgery led to complete hemostasis in rats during and after lingual frenectomy. Zero bleeding was assessed during surgeries and after diode laser surgeries in anticoagulated rats. Laser-induced hemostasis offered an alternative solution to the controversial issue of intraoperative and postoperative bleeding control in patients on anticoagulation therapy.

Diode laser therapy in the management of chronic periodontitis - A clinico-microbiological study

Introduction

Chronic periodontitis (CP) is an infectious disease resulting in inflammation of the supporting tissues of the teeth with progressive attachment loss and bone loss. This study aimed to evaluate the effect of 980-nm diode laser, as an adjunct to scaling and root planing (SRP) in the management of CP.

Methodology

A total of 40 systemically healthy subjects diagnosed with CP were randomly assigned into two groups G1 (SRP and sham application of laser) and G2 (SRP and laser irradiation) with equal numbers in each. The levels of Porphyromonas gingivalis (Pg) were estimated from plaque samples using real-time polymerase chain reaction. Clinical and microbiological parameters were assessed at baseline, 4–6, and 12–14 weeks posttreatment in both groups.

Results

A gradual reduction in the levels of Pg and improvement in clinical parameters were observed from baseline to 4–6 and 12–14 weeks in both groups. However, the comparison between groups, although clinically relevant, was not found to be statistically significant.

Conclusion

Although a 980-nm diode laser may not have any added benefit compared with SRP, it may emerge as an effective non-surgical treatment option in advanced periodontitis with complex inaccessible subgingival niches where comprehensive periodontal care may not be feasible.

Lasers in Apicoectomy: A Brief Review

Since the invention of laser, various applications for lasers in endodontics have been proposed, such as disinfection of the root canal system, canal shaping, pulp diagnosis, and apico-ectomy. One of the major applications of laser in endodontics is apicoectomy. The aim of this article is to review the benefits and drawbacks of laser applications in apicoectomy, including effect on apical seal, effect on dentin permeability, effect on postsurgery pain, effect on crack formation, effect on root-end morphology, effect on treatment outcome, and connective tissue response to laser-treated dentin.

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.

Laser-based Disinfection of the Root Canal System: An Update

Microorganisms have been considered to have played a critical role in the initiation and development of pulpo-periapical diseases. Some evidences have shown that mechanical instrumentation may leave considerable portions of canal surfaces undebrided. Therefore, some supplemental methods, such as the use of chemical solutions and/or lasers, have been introduced to further disinfect the complicated canal anatomy and destroy as many microorganisms as possible. The purpose of this review was to address a brief review of characteristics of lasers and their effects to disinfect the root canal in endodontics.

The Versatility of 980 nm Diode Laser in Dentistry: A Case Series

Introduction: Laser surgery has been considered a popular alternative over conventional modalities in dentistry during the last few years. Among different types of lasers, diode lasers have gained special attention in oral soft tissue surgery. Case Reports: Five patients were referred to a private office. After careful evaluation of medical history and oral examination, oral diagnosis and treatment plan of each patient was established as follows: (1) A 21-year-old female with ankyloglossia (tongue-tie); (2) A 65-year-old female with a poor denture fit needing vestibuloplasty and frenectomy; (3) A 10-year-old male patient with pigmented gingiva in mandible and maxilla; (4) A 14-year-old female needing exposure of maxillary right canine for bracket bonding; and (5) A 25-year-old female patient who has a gingival maxillary frenum with a nodule. The treatment plan for all the patients was laser surgery with diode laser at 980 nm, in continuous mode. Results: All the patients experienced normal healing process with no postoperative complications. Favorable outcomes of laser surgery were observed on follow-up sessions. Conclusion: Considering the versatility of the 980 nm diode laser in oral soft tissue surgeries and the advantages of laser surgery, this study suggests the use of 980 nm diode laser in this regard.

Commentary: Is There Clinical Benefit From Using a Diode or Neodymium:Yttrium-Aluminum-Garnet Laser in the Treatment of Periodontitis?

Despite a quarter of a century of laser research, there is a persistent debate regarding the efficacy of dental lasers in the treatment of periodontitis or periodontal maintenance therapy. There are many claims and much hyperbole surrounding the use of lasers, either as a monotherapy or adjunctive to scaling and root planing, to treat periodontitis. There is little evidence that using a diode or neodymium:yttrium-aluminum-garnet laser adds clinical value over and above conventional non-surgical or surgical periodontal treatment. There is a significant need for better designed human clinical trials. Data from such trials should be analyzed according to initial probing depth and characteristics of the treated sites, such as non-molar, molar flat surfaces, and molar furcations, and evaluated for long-term post-treatment results.

The extended tentacles of laser - From diagnosis to treatment in orthodontics: An overview

Since the introduction of lasers in dentistry in the mid-1990's, research in laser supported dental therapies is progressing at a rapid pace. Orthodontics is no exception. In orthodontics, lasers have many diagnostic, therapeutic, and biomodulating applications. To update the various applications of lasers in orthodontics. Lasers work by delivering energy in the form of light. Laser, striking the biological tissues can either get reflected, absorbed or scattered depending on several factors. Depending on the fate of the emitted laser, it can be applied for different diagnostic, therapeutic and surgical procedures. The knowledge and understanding of different types of lasers and its specific applications is a prerequisite before it can be applied beneficially. In Orthodontics, the versatility of laser has expanded into bonding, curing, debonding, imaging, growth modification, pain reduction, etc. Definitely laser has extended its tentacles from diagnosis to treatment in orthodontics.

Use of a Carbon Dioxide Laser as an Adjunct to Scaling and Root Planing for Clinical New Attachment: A Case Series

INTRODUCTION

Severe, chronic periodontitis (CP) is typically treated either with scaling and root planing (SRP) or surgical therapy in an effort to gain clinical attachment. The advantage of non-surgical therapy is decreased morbidity to the patient; however, the site typically heals by formation of a long junctional epithelium. The advantage of surgical therapy is access for debridement and the use of bone or bone substitutes in combination with a barrier membrane for epithelial exclusion. Compared with a non-surgical approach, surgical therapy is more invasive, and patient acceptance of treatment is typically more challenging. The use of lasers in dentistry appears to be rapidly increasing, as evidenced by the influx of new lasers into the dental market as well as numerous anecdotal reports of beneficial results with their use.

CASE SERIES

This report presents a novel approach to the treatment of severe CP using a carbon dioxide (CO₂) laser in combination with SRP. This study presents the findings of 17 patients (nine males and eight females, aged 34 to 71 years; mean age: 54 years) that were compared in a split-mouth design and followed for 3 months. To the best of the authors' knowledge, this is the first reported case series using a CO₂ laser for de-epithelialization in combination with SRP for the treatment of CP.

CONCLUSION

Sites treated with the CO₂ laser tended to show a greater decrease in probing depths, greater amounts of recession, and greater gains in clinical attachment levels, but the results were not statistically significantly better than SRP alone.

Tissue restoration after improper laser gingivectomy: A case report

We report the case of 27-year-old female patient applied to our clinic with several pain at her upper teeth and weakness complaints. Anamnesis revealed that she experienced laser gingivectomy to have remarkable teeth. Clinical examination showed that maxillar alveolar bone was partially uncovered with gingivae and periosteum. Interproximal necrosed area was observed. She had sensitivity at her maxillar anterior teeth. Furthermore, she was so anxious and depressed. In order to ensure more blood supply and clot formation, perforations on uncovered cortical bone was prepared. Avoiding from infection antibiotic, antiseptic gel and for epithelization vitamin E gel were prescribed. During one month she was recalled every third day. Recall times diminished periodically, as new tissue evolves. Although laser’s irreversible photothermal effects on soft and hard tissue, after a year all denuded areas were covered with healthy tissues without any surgical procedures. Histopathologic comparing showed severe lymphocyte infiltration and increased fibrosis and kollagenization in restored gingiva, additionally epithelial loss was observed. Since there is not a case report about the complications of laser gingivectomy in literature, we tried to represent a treatment plan that may be elucidative for clinicians.

A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

BACKGROUND AND OBJECTIVES

Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG) laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation.

SUBJECTS AND METHODS

A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage.

RESULTS

Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change.

INTERPRETATION AND CONCLUSION

In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface, but removed more tooth structure. The laser treated specimens showed rough surfaces without much residual deposit or any other sign of morphological change.

Transcanalicular laser dacryocystorhinostomy using low energy 810 nm diode laser

Background:

Hypertrophic scarring may be a cause of failure after transcanalicular laser dacryocystorhinostomy (DCR) surgery. This hypertrophic scarring results from tissue charring and excessive coagulation, which may be caused by the high laser energy. We have evaluated the use of low energy settings to prevent hypertrophic scarring, for a successful outcome.

Aims:

To perform and evaluate transcanalicular laser DCR using low energy 810 nm diode laser.

Design:

Interventional, non-comparative, case series.

Materials and Methods:

Patients with nasolacrimal duct obstruction and chronic dacryocystitis, who needed DCR, and were fit for surgery under local anesthesia, were recruited to undergo transcanalicular laser DCR using a 810 nm diode laser. The outcome was measured by the patency of the lacrimal passage, as indicated by the relief in the symptoms and the patency on syringing at the last follow-up. The surgical time and surgical complications were noted.

Statistical Analysis Used:

Descriptive analysis.

Results:

The study included 94 patients. The average age was 30.1 years (range 15 - 69 years). Seventy (74.4%) patients were female. Eight patients had failed external DCR. Per-operative patency of the passage was obtained in all the patients. Average surgical time was seven minutes (5 – 18 minutes). At the end of the study period of one year, a successful outcome was seen in 85 patients (90.5%). There were eight patients of previous failed DCR surgeries, and six of them achieved a cure at the end of follow-up.

Conclusions:

Transcanalicular Laser DCR can be safely performed using a low power 810 nm diode laser. The surgery is elegant, minimally invasive, allows fast rehabilitation, and has an excellent success rate.

Perceptions of soft tissue laser use in orthodontics

OBJECTIVES

To compare attitudes of orthodontists, periodontists, and general dentists regarding the use of soft tissue lasers by orthodontists during the course of orthodontic treatment.

MATERIALS AND METHODS

An analogous survey was developed to evaluate and compare the current opinions of a representative sample (n  =  538) of orthodontists (61.3%), periodontists (24.3%), and general dentists (14.3%) regarding orthodontists' use of soft tissue lasers.

RESULTS

The majority (84%) of orthodontists, periodontists, and general dentists regarded the use of a soft tissue laser by orthodontists as appropriate. When compared to orthodontists and general dentists, a lower percentage of periodontists indicated that soft tissue laser use by orthodontists was appropriate (P < .01). For each of the eight specific soft tissue laser procedures investigated, periodontists reported a significantly lower level of appropriateness than did orthodontists and general dentists (P < .01). Around 75% of the total sample believed that referral would not be affected by the use of soft tissue lasers by orthodontists.

CONCLUSIONS

Orthodontists, periodontists, and general dentists differed in their opinions of the perceived appropriateness of soft tissue laser use by orthodontists, with periodontists reporting a lower level of appropriateness. Clinicians need to communicate effectively to ensure that orthodontic patients in need of adjunctive soft tissue surgery are treated to the accepted standard of care.

Photodynamic therapy in the treatment of chronic periodontitis: a systematic review and meta-analysis

This meta-analysis was conducted to investigate the efficacy and safety of antimicrobial photodynamic therapy used alone or adjunctive to scaling root planing in patients with chronic periodontitis. The meta-analysis was conducted according to the QUOROM statement and recommendations of the Cochrane Collaboration. An extensive literature search was performed on seven databases, followed by a manual search. Weighted mean differences and 95% confidence intervals were calculated for clinical attachment level, probing depth and gingival recession. The I(2) test was used for inter-study heterogeneity; visual asymmetry inspection of the funnel plot, Egger's regression test and the trim-and-fill method were used to investigate publication bias. At 3 months, significant differences in clinical attachment level (p = 0.006) and probing depth reduction (p = 0.02) were observed for scaling root planing with antimicrobial photodynamic therapy, while no significant differences were retrieved for antimicrobial photodynamic therapy used alone; at 6 months no significant differences were observed for any investigated outcome. Neither heterogeneity nor publication bias was detected. The use of antimicrobial photodynamic therapy adjunctive to conventional treatment provides short-term benefits, but microbiological outcomes are contradictory. There is no evidence of effectiveness for the use of antimicrobial photodynamic therapy as alternative to scaling root planing. Long-term randomized controlled clinical trials reporting data on microbiological changes and costs are needed to support the long-term efficacy of adjunctive antimicrobial photodynamic therapy and the reliability of antimicrobial photodynamic therapy as alternative treatment to scaling root planing.

Management of ear lobule keloids using 980-nm diode laser

The objective of the study was to evaluate the 980-nm diode laser in conjunction with corticosteroids in the treatment of ear lobule keloids. Several methods have been described for the treatment of keloid scars, but none of them have been 100% successful. Advances in laser techniques have enabled surgeons to define the most appropriate lasers for use in the treatment of different scar types. The diode laser pulses are delivered interstitially in a single repeated mode in non-overlapping sites using a bare optical fiber, followed by intralesional triamcinolone acetonide injection. The number of sessions varies between two to five for the management of more than 75% of keloid size, with a total success rate of 75% and no recurrence in the follow-up of 12 months. The technique used proved to be effective in the treatment of ear lobule keloids.

Soft tissue laser in orthodontics

Today a lot of minor cosmetic surgery operations on the gingiva can easily be carried out directly by the orthodontist with a small quantity of topical anaesthetic and the use of a soft tissue laser. The Diode laser is the most commonly used laser in dentistry for minor surgery to the soft tissues. This kind of laser offers numerous advantages with respect to traditional or electric scalpels. In this article the authors will analyse several typical uses of the diode laser in daily orthodontic practice.

Evaluation of pain levels after Nd: YAG laser and scalpel incisions: an experimental study in rats

BACKGROUND

Postoperative pain is a recognized sequel of periodontal surgery. The pain experience has been shown to peak in the first 24 hours following the procedure, and to decrease rapidly in subsequent days. The aim of the present study was to evaluate the pain levels following scalpel- and laser-incision of rat hind paws.

METHODS

The study was carried out on 10 albino Wistar male rats. Rats were randomly assigned to two groups: Group I (n = 5, laser surgery), or Group II (n = 5, conventional surgery with scalpel). For measuring mechanical hyperalgesia, the nociceptive threshold of the hind paw after mechanical stimulation was quantified using a Basile algesimeter. The measurements were done before the surgery and on the postoperative 1(st), 2(nd), 3(rd), and 7(th) days.

RESULTS

While the pain levels of the groups were similar before the surgical procedures, the laser-applied rats had significantly fewer nociceptive thresholds of the hind paw after mechanical stimulation compared with the scalpel-incised rats on the postoperative 1(st), 2(nd), 3(rd), and 7(th) days. Functional complications were not observed in the laser groups at three days after the surgery.

CONCLUSION

The results suggested that, for soft tissue surgery, Nd: YAG lasers have often led to shorter operative times, less pain, and fewer postoperative adverse events.

Soft-tissue lasers in orthodontics: an overview

Soft-tissue lasers have numerous applications in orthodontics, including gingivectomy, frenectomy, operculectomy, papilla flattening, uncovering temporary anchorage devices, ablation of aphthous ulcerations, exposure of impacted teeth, and even tooth whitening. As an adjunctive procedure, laser surgery has helped many orthodontists to enhance the design of a patient's smile and improve treatment efficacy. Before incorporating soft-tissue lasers into clinical practice, the clinician must fully understand the basic science, safety protocol, and risks associated with them. The purpose of this article is to provide an overview regarding safe and proper use of soft-tissue lasers in orthodontics.

Lasers and soft tissue: periodontal therapy

Periodontology exists as a major specialty within clinical dentistry that has developed through the extensive research carried out into all parameters pertaining to a 'best practice' approach. With the advent of surgical lasers into clinical dentistry, considerable interest has been shown in the possible benefits that might be derived from the adjunctive effects of bacterial control and haemostasis that are associated with laser use. Despite the number of publications on the subject, there is still controversy over the use of lasers in periodontology. The following paper will outline the procedures that have been advocated for laser use and provide a review of the literature.

Long-term effect of pulsed Nd:YAG laser irradiation on cultured human periodontal fibroblasts

BACKGROUND AND OBJECTIVES

The purpose of this study was to investigate the long-term effect of Nd:YAG laser irradiation on cultured human periodontal fibroblasts (hPF).

STUDY DESIGN/MATERIALS AND METHODS

The cultured hPF were irradiated by pulsed Nd:YAG laser. The power delivery was 50 mJ x 10 pps (pulse per second) with irradiation duration 60, 120, 180, or 240 seconds. The viability and collagen content of laser-irradiated hPF were assessed on day 5 after laser treatment. Light microscope and transmission electron microscope (TEM) were used to observe cytomorphological change. The irradiated hPF cultured in mineralizing medium for 28 days were examined by alizarin red S and Von Kossa stain.

RESULTS

The cellular viability and collagen content of hPF decreased after Nd:YAG laser irradiation. Cell damage was noted with retraction of cellular processes, loss of normal architecture, and lysis of some cells. However, survived hPF proliferated and migrated to the cell-debris-associated deposits. The electron-dense cytoplasm and amorphous organelles in laser-damaged cells was revealed by TEM. In vitro mineralization was demonstrated in the long-term laser-irradiated hPF cultured in mineralizing medium.

CONCLUSION

Nd:YAG laser irradiation induced partial loss of cellular viability and collagen content. The co-existence of viable cells and progressive degeneration of laser-damaged cells was associated with the in vitro mineralization of hPF.

Histologic Evaluation of Three Methods of Periodontal Root Surface Treatment in Humans

BACKGROUND

Removing subgingival plaque and calculus is a major goal of periodontal treatment. Few attempts have been made to evaluate the use of lasers for root surface debridement in periodontal therapy. The aim of the present study was to compare, histologically, the effects of hand instrumentation, ultrasonic instrumentation, and CO2 lasers on the root surfaces of teeth treated in situ.

METHODS

A total of 33 teeth scheduled for extraction due to severe periodontal disease were divided into three groups. In the first group, teeth were treated by ultrasonic bactericidal curettage (UBC) with an ultrasonic scaler; in the second group, teeth were treated by hand instrumentation; and in the third group, after hand instrumentation, roots were lased by a CO2 laser. The samples were then processed for histological examination.

RESULTS

In the first and second groups, plaque and calculus were present in interradicular septa, lacunae, and surface concavities. In the third group, surfaces of specimens treated by a low-power defocused CO2 laser showed areas devoid of cementum, with completely sealed dentinal tubules, and no bacterial cell remnants.

CONCLUSIONS

The CO2 laser treatment, used at low power and in the defocused mode, combined with traditional mechanical instrumentation, could improve root surface debridement of periodontally involved teeth. More extensive, long-term studies are needed to confirm this hypothesis.

Effect of Low-Level Er:YAG Laser Irradiation on Cultured Human Gingival Fibroblasts

BACKGROUND

Low-level laser irradiation has been reported to enhance wound healing. Activation of gingival fibroblasts (GF) has a potential for early wound healing in periodontal treatment. The present study aimed to investigate the direct effect of low-level Er:YAG laser irradiation on gingival fibroblasts proliferation in order to clarify the laser effect on healing.

METHODS

Cultured human gingival fibroblasts (hGF) were exposed to low-power, pulsed Er:YAG laser irradiation with different energy densities ranging from 1.68 to 5.0 J/cm(2). The cultures were analyzed by means of trypan blue staining and counted under a light microscope. The effect of Er:YAG laser on hGF was also evaluated using a transmission electron microscope (TEM).

RESULTS

Cultures irradiated with Er:YAG laser presented faster cell growth when compared with untreated controls. This difference was statistically significant. Transmission electron microscopy revealed rough endoplasmic reticulum, prominent Golgi complexes, and mitochondria after laser irradiation.

CONCLUSIONS

Our results showed that the low-level Er:YAG laser irradiation stimulates the proliferation of cultured gingival fibroblasts. The optimal stimulative energy density was found to be 3.37 J/cm(2). This result suggests that Er:YAG laser irradiation may be of therapeutic benefit for wound healing.

Removal of Epithelium in Periodontal Pockets following Diode (980 nm) Laser Application in the Animal Model: Anin VitroStudy

OBJECTIVE

The purpose of this study was to examine the removal of the epithelium in the periodontal pocket using a diode (980 nm) laser in comparison with the conventional techniques in an animal experimental model.

BACKGROUND DATA

The goal of periodontal therapy is to reduce the bacterial deposits in the pockets and to enhance the clinical attachment. Different surgical techniques have been used in the past, which control the epithelial migration and promote the connective tissue formation.

MATERIALS AND METHODS

The buccal pockets of the posterior teeth in 10 freshly sacrificed adult pigs were scaled by three different examiners (with different levels of experience in periodontal surgery) using conventional curettes. The lingual pockets were treated using a diode (980 nm) laser. The laser was used in a continuous wave (c. w.) mode with two different power settings (2 and 4 Watts) with a 300-microm-thick glass fiber. The instrumentation period revealed 15 sec in all of the sites. Soft tissue biopsies of the instrumented sites were removed and examined histologically.

RESULTS

In all of the lased sections, no epithelial remnants were found. The laser with a low power was able to remove the thin pocket epithelium in the same way regardless of the level of surgical experience of the examiner. A high-power setting presented significant damage to the underlying connective tissues. The sites, which were instrumented with the conventional curettes, demonstrated significant epithelial remnants in all of the tissues regardless of the level of periodontal surgical experience.

CONCLUSION

The histological findings presented in this study showed that instrumentation of the soft periodontal tissues with a diode laser (980 nm) leads to a complete epithelial removal in comparison to conventional treatment methods with hand instruments (independent of the clinician's experience).

Ultrastructural analysis of bone tissue irradiated by Er:YAG Laser

BACKGROUND AND OBJECTIVES

The use of erbium:yttrium aluminum garnet (Er:YAG) laser has been suggested for bone ablation, however, little is known about the nature of the tissue after irradiation. This study was aimed to analyze the ultrastructure of bone tissue treated with Er:YAG laser, as compared to those treated with CO(2) laser and bur drilling.

STUDY DESIGN/MATERIALS AND METHODS

Parietal bones of Wistar rats were treated and analyzed by light microscopy, transmission electron microscopy (TEM), electron diffraction analysis and energy dispersive X-ray spectroscopy (SEM-EDX).

RESULTS

This study demonstrated that Er:YAG laser irradiation resulted in a very thin changed layer of approximately 30 microm thickness, which consisted of two distinct sub-layers: a superficial, greatly altered layer and a deep, less affected layer.

CONCLUSIONS

The major changes found on bone surface after Er:YAG laser irradiation consisted of micro-cracking, disorganization, and slight recrystallization of the original apatites and reduction of surrounding organic matrix.

Effects of Nd:YAG and CO2Laser Treatment and Ultrasonic Scaling on Periodontal Pockets of Chronic Periodontitis Patients

BACKGROUND

The aim of the present study was to compare the effectiveness of Nd:YAG and CO2 laser treatment to that of ultrasonic scaling used as monotherapies by examining clinical parameters, subgingival microflora, and interleukin-1 beta (IL-1beta) in gingival crevicular fluid (GCF).

METHODS

Eighteen patients, each of whom had 2 or more sites with probing depth measuring > 5 mm, were included this clinical trial. The 41 sites were randomly assigned treatment with either Nd:YAG laser alone (n = 14, 100 mj, 20 pps, 2.0 W, 120 seconds), CO2 laser alone (n = 13, 2.0 W, 120 seconds), or ultrasonic scaling alone (n = 14, maximum power, 120 seconds). At baseline and at 1, 4, and 12 weeks, clinical measurements (plaque index, PI; gingival index, GI; probing depth, PD; clinical attachment level, CAL; and bleeding on probing, BOP) were performed and subgingival plaque and GCF sampled. A quantitative analysis of Porphyromonas gingivalis was carried out using real-time polymerase chain reaction (PCR) procedures. The amounts of IL-1beta were estimated by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Decreased inflammation and PD were observed in all 3 groups after treatment. A microbiological analysis indicated significant decreases in P. gingivalis in the Nd:YAG and scaling groups at 1, 4, and 12 weeks compared to baseline (P < 0.05). The amount of GCF significantly decreased in the Nd:YAG and scaling groups at 12 weeks. The amount of IL-1beta increased in the CO2 group from baseline to 1 week (P < 0.05). The Nd:YAG group tended to show a decrease in IL-1beta from 1 to 12 weeks, although these data were not statistically significant.

CONCLUSIONS

Our data suggest that Nd:YAG laser and ultrasonic scaling treatments showed significant improvements regarding the clinical parameters and subgingival microflora compared to the baseline, but no significant difference was observed between the 3 groups.

Lasers in periodontics

Publicity about the use of lasers in dentistry has generated considerable interest in both professional and lay audiences. The purpose of this report is to provide information for members of the dental profession about the current and potential application of laser technology to periodontal practice. This report was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology.

Improvement of macromolecular clearance via lymph flow in hamster gingiva by low-power carbon dioxide laser-irradiation

BACKGROUND AND OBJECTIVE

Although therapeutic effects of low-power laser-irradiation on periodontal disease have been reported, little is known about the biological effects of laser-irradiation in the gingiva. Recently we reported that topical warming stimulated macromolecular clearance via lymph flow in hamster gingiva. This study was conducted to investigate whether low-power laser-irradiation affects macromolecular clearance via the lymph flow in the gingiva.

STUDY DESIGN/MATERIALS AND METHODS

We injected 14C-methylated albumin into the mandibular gingiva of anesthetized hamsters followed by topical carbon dioxide (CO2) laser-irradiation (30 seconds, 0.5-1.5 W). We measured the clearance of radiolabeled albumin from the gingiva and its drainage into submandibular lymph nodes during 10 minutes.

RESULTS

The clearance of the radiolabeled albumin from the gingiva and the influx into the submandibular lymph nodes were increased by CO2 laser-irradiation.

CONCLUSION

Low-power CO2 laser-irradiation improves macromolecular clearance via the lymph flow in hamster gingiva.

Effects of Nd:YAG laser irradiation on cultured human gingival fibroblasts

BACKGROUND AND OBJECTIVE

The Nd:YAG laser has been proposed to apply in minor soft tissue surgery, including various periodontal procedures. However, little information is available regarding the direct effect of Nd:YAG laser on gingival fibroblasts, which play an important role in the early healing processes of periodontal repair.

STUDY DESIGN/MATERIALS AND METHODS

Nd:YAG laser irradiation was performed in pulsed mode on human gingival fibroblasts, which was derived from healthy human gingiva by an explant method. The size of laser diode was 400 microm in diameter. The parameters in laser delivery were pulse energy (50-150 mJ), power output (1.0-3.0 W), pulse rate (10-30 pps), and fixed duration of irradiation (10 seconds). The cell cultures were analysed by cytomorphologic examination under phase-contrast and scanning electron microscope. The vitality was also examined with the help of MTT staining.

RESULTS

The area of laser damage on cell culture was circular in shape, with diameter beyond the size of laser diode. By scanning electron microscopy, we observed the cellular damage of cultured gingival fibroblasts induced by Nd:YAG laser irradiation, comparable with the progressive increased power settings. The cytomorphologic changes ranged from disappearance of cellular boundary, loss of identifiable cellular nucleus, and finally cell contraction and vacuolization. Significant decrease in cellular vitality (14% approximately 44%) after laser treatment with irradiation distance of nearly contact was noted. However, 2 mm defocusing irradiation with the same power settings did not significantly decrease cellular vitality.

CONCLUSION

Our study demonstrated the cell damaging effects of Nd:YAG laser, ranging from degeneratively cytomorphologic change to cell death, on the cultured human gingival fibroblasts. It provided the dentist a chance to understand the potential hazard of laser application in periodontal treatment. If the energy output is enough for the clinical purposes, Nd:YAG laser with lower pulse energy and corresponding pulse rate should be selected to minimize the damage on adjacent soft tissue.