Laser physics and a review of laser applications in dentistry for children

Clinical evaluation of pain perception and surgical wound healing after lower labial frenectomy with diode laser technique: pilot study

The aim of this study was to evaluate the postoperative period of diode laser frenectomies of the lower labial frenulum (LLF) with anomalous insertions and the perceptions of postoperative pain and wound healing. This cross-sectional pilot study evaluated 3 patients who underwent mandibular labial frenectomy with a diode laser between April 2024 and July 2024. Individuals were divided into two groups according LLF insertion type and the parameters evaluated were gender, age, traumatic brushing, dentin hypersensitivity (DH), traumatic brushing, postoperative pain presence, healing, analgesic use and periodontal parameters, with follow-up occurring up to 90 days after frenectomy. Statistical analyses were performed by frequency of categorical variables, Fisher's exact test and G test were used for intra and intergroup comparisons and the Wilcoxon test was used to compare different postoperative times, with the level of significance set at 0.05 (p < 0.05). The mean age of the sample was 34.6 years and there was a predominance of female participants (n = 2/ 66.6%), we verified that 2 (66.6%) patients presented a bifurcated frenulum insertion and 100% presented mild to intense DH and gingival recession. In the postoperative period, 100% of individuals reported pain and visual dissatisfaction with the scar until the 4th day of follow-up and after 30 days of follow-up only 1 individual remained with pain and visual dissatisfaction with the scar and no evaluated parameter showed statistical significance. Diode laser frenectomy proved to be effective in controlling postoperative pain, improving healing and reducing bleeding.

Diode Laser Intended Frenotomy Procedure for High Frenal Attachment Causing Gingival Recession: A Case Presentation

The alveolar mucous membrane, the gingiva, and the underlying bone are fixed to the lip and cheek by the frenum, a fold in the mucous membrane. The surgical process known as a frenectomy involves completely removing the frenum that connects it to the bone. Traditional frenectomy involves using a blade, while a more recent technique is frenectomy assisted by a laser. When the frenum has an atypical connection, a labial or lingual frenectomy is performed. In this instance, there is an abnormal frequency of attachment, which puts the patient's appearance, causing midline diastema and plaque control, at serious risk and could result in mucogingival impairment. This case study describes how diode laser therapy was used to successfully treat a female patient who was suffering from sensitivity.

Evaluation of the effect of self-assembling peptide and fluoride varnish, alone or in combination with laser irradiation, on artificial enamel caries: a SEM/EDS and Micro-CT study

OBJECTIVE

The aim of this study was to investigate the effect of remineralization agents such as fluoride varnish and P11-4, alone and in combination with Er: YAG laser, on in-vitro hard tissue repair in artificial enamel lesions.

MATERIALS AND METHODS

A total of sixty enamel surfaces of 4 × 5 mm in size were created on both the buccal and lingual sides of thirty extracted wisdom teeth. Remineralization agents were applied to the specimens that were grouped as follows: Group 1, control; Group 2, fluoride varnish (FV); Group 3, P11-4; Group 4, laser; Group 5, laser + FV; and Group 6, laser + P11-4. The fluorescence level was determined with DiagnoDent. The enamel mineral density, area and volume, and caries lesion area and volume were determined with micro-computed tomography (µCT), surface features were evaluated using scanning electron microscopy (SEM), and elemental analysis was performed using energy dispersive x-ray spectroscopy (EDS) .

RESULTS

For specimens treated only with self-assembling peptide P11-4, the caries lesion area (mm2) values were 38.19 and 21.62, and the caries lesion volume (mm3) values were 6.27 and 2.99, respectively for pre- and post-treatment. In combination usage of self-assembling peptide P11-4 and laser, the caries lesion area (mm2) values were 38.39 and 16.91, and the caries lesion volume (mm3) values were 11.15 and 3.64, respectively for pre- and post-treatment. In the application of the P11-4 alone and in combination with laser, there was a statistically significant decrease in DiagnoDent values, an increase in enamel volume(mm3),enamel area(mm2) and mineral density(g/cm3) values and a decrease in caries lesion volume(mm3) and area(mm2) obtained by µCT, and an increase in %Ca and %F values obtained by SEM/EDS analysis (p < 0.05). It was discovered that the samples treated with P11-4 had a considerably higher rise in the Ca/P ratio than the samples treated with FV (p < 0.05). The calcium content increased significantly more when P11-4 application was combined with laser irradiation (p < 0.05).

CONCLUSIONS

The combined use of self-assembling peptide P11-4 and laser accelerated the remineralization process and increased the remineralization capacity.

CLINICAL RELEVANCE

FV and P11-4, alone or in combination with laser, can be successfully used as remineralization agents in initial enamel caries.

Advanced Applications in Pediatric Dentistry: A Worldwide Perspective of the Last 13 Years

The enhancement of the clinical management of growing patients has always been a great challenge for orthodontists and pediatric dentists [...].

Surgical treatment of hereditary gingival fibromatosis by diode laser: Report of five rare cases in the same family

The pathogenesis of hereditary gingival fibromatosis (HGF) is largely unknown; however, the removal of excess tissue may often be necessary as it often causes aesthetic and functional problems. Gingivectomy is usually a treatment option that can be performed using a scalpel, cryotherapy, electrosurgery, or laser. This paper aims to evaluate the results of HGF treatments using a diode laser of five people from the same family. Three members of a family of five (two females and three males; 9-36 years old) underwent gingivectomy with a 3 W 300-micron fiber-tipped diode laser (Doctor Smile, Vicenza, Italy) at 810 nm wavelength. While all teeth of one member were extracted, the other member refused treatment. Relapse occurred in three members due to poor oral hygiene. The diode laser was reapplied and oral hygiene instructions were repeated. Patients were followed during the postoperative period for up to two years. HGF is a rare condition that clinicians should pay attention to in the diagnosis, treatment, and follow-ups. Since recurrences are due to dental plaque, oral hygiene instructions are essential and compliance is mandatory. Although there are many treatment approaches, the diode laser is the most indicated method due to many advantages such as providing a bloodless and more sterile operation field, performing an atraumatic surgery, ensuring earlier and ideal recovery, and minimizing postoperative pain.

Labial Frenectomy using Laser: A Scoping Review

Labial frenectomy is a surgical technique, that aims to remove the frenulum with its attachment to the underlying bone. Frenectomy, is indicated if the frenulum attachment causes midline diastema, gingival recession, hindrance in maintaining oral hygiene, or if it interferes with lip movements and for prosthetic needs. A labial frenectomy can be performed either by the routine scalpel technique, electrocautery, and most recently medical lasers. The aim of this study was to evaluate, whether the laser technique is more effective than the conventional surgical technique, and whether there are differences between the different types of lasers. The scoping review was conducted and prepared on the basis of the indications of the PRISMA guidelines (PRISMA Extension for Scoping Reviews, PRISMA-ScR) of PRISMA checklist, and nine papers were considered admissible to the qualitative analysis for the following outcomes: bleeding during intervention, use of sutures, duration of the intervention, and use of analgesic drugs in the days following the intervention. This review suggests that laser-performed labial frenectomy is faster and offers better intra- and postoperative management; however, due to the limited number of available papers, the final results of the present review are not absolute.

Does luminosity and smear layer influence 810 nm laser energy transmission through human dentine?

PURPOSE

The aim of this study was to evaluate the influence of luminosity values and smear layer on transmission characteristics of 810 nm near infrared laser energy through dentine, using extracted human teeth.

METHODS

A total of 200 teeth treated with endodontic medicaments to cause discolouration (Ledermix, Doxypaste or Odontopaste) were selected, to give a range of values for tooth shade (luminosity values). Sectioned teeth had smear layer created or removed. Near-infrared laser energy transmission was assessed using an 810 nm diode laser (90 mW, CW mode) with the tip placed at 2 mm and 4 mm from the external root surface, and a laser power metre.

RESULTS

Both tooth shade and smear layer had independent attenuating effects. Transmission of laser energy was significantly lower in teeth with darker shades. There was a strong positive correlation between relative luminosity (lighter tooth colour) and transmitted laser power (r = 0.9271 for the Spearman rank correlation, P = 0.0022). When a smear layer was present, this significantly reduced the transmission of laser energy through the sample, compared to when no smear layer was present.

CONCLUSION

The results of this laboratory study highlight the attenuating influence of a darker tooth shade and the presence of smear layer on the transmission of 810 nm light when directed onto the surface of human dentine. Such effects may be relevant to photo biomodulation, Photodynamic Therapy and other dental laser treatments.

Impacted Palatal Canines and Diode Laser Surgery: A Case Report

INTRODUCTION

Maxillary canine is the most frequent dental element that could likely remain impacted in the bone structure, with a percentage between 1 and 5%. This study presents a case report using a diode laser for surgical-orthodontics disinclusion of a palatal mucosal impacted permanent left upper canine (2.3) and the simultaneous application of an orthodontic bracket.

METHODS

After cementation of the trans-palatal bar to the upper first molars with a hook for orthodontic traction, local anaesthesia with articaine was performed, followed by surgical operculectomy using a diode laser (810 nm wavelength, continuous wave mode with a power output of 3 W, and a 0.4 mm diameter optical fiber), and the orthodontic bracket with a passive metal looped ligature was applied. Subsequently, active elastic traction was applied on 2.3 and the upper arch was bonded for the application of a series of orthodontic wires, lace-back, and metal ligatures. A progressive reactivation of the elastic traction and extraction of 6.3 was necessary to translate the canine into the correct arch position.

RESULTS

Diode laser surgical-orthodontic disinclusion of impacted upper canine was performed successively, resulting in a dry surgical field ideal for orthodontic bracket adhesion. No pain and no swelling have been reported from the patient. The orthodontic treatment allowed the canine to be moved to the correct position in the arch.

CONCLUSIONS

This case showed that the diode laser is a valid alternative for the surgical-orthodontic disinclusion of an included tooth element.

Expert consensus on early childhood caries management

Early childhood caries (ECC) is a significant chronic disease of childhood and a rising public health burden worldwide. ECC may cause a higher risk of new caries lesions in both primary and permanent dentition, affecting lifelong oral health. The occurrence of ECC has been closely related to the core microbiome change in the oral cavity, which may be influenced by diet habits, oral health management, fluoride use, and dental manipulations. So, it is essential to improve parental oral health and awareness of health care, to establish a dental home at the early stage of childhood, and make an individualized caries management plan. Dental interventions according to the minimally invasive concept should be carried out to treat dental caries. This expert consensus mainly discusses the etiology of ECC, caries-risk assessment of children, prevention and treatment plan of ECC, aiming to achieve lifelong oral health.

Effect of Photobiomodulation on Periodontal Ligament Cells Under Inflamed and Nutrient-Deficient Conditions Simulating Damaged Cells of Avulsed Teeth: An In Vitro Study

Background: The prognosis of replanted teeth is depended on the vitality of periodontal ligament cells residual on the root surface. Photobiomodulation has photobiological effects that can promote cell vitality. The study aimed to explore the effect of photobiomodulation on the periodontal ligament cells under inflamed or starved conditions mimicking clinically damaged periodontal ligament cells of avulsed teeth and provide the adjuvant procedure for tooth replantation. Materials and methods: Normal, starved, or inflamed periodontal ligament cells were irradiated with an 808 nm laser at densities of 0, 1, 3, 5, or 10 J/cm². The cell counting kit-8 (CCK-8) assay and scratch test were applied to determine the effects on the proliferation and migration of cells. Anti-inflammatory effects were assessed according to the mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) measured by reverse-transcription polymerase chain reaction. Osteogenic capacity was evaluated by alkaline phosphatase (ALP) staining, ALP activity assay, Alizarin Red S staining, and ALP and osteocalcin (OCN) mRNA expression. Results: The CCK-8 assay and scratch test demonstrated that the 808 nm laser significantly promoted proliferation and migration of normal condition periodontal ligament cells at a density of 3 J/cm² versus 5 J/cm² under the starved and inflamed conditions. Moreover, the 808 nm laser had anti-inflammatory effects and promoted osteogenesis of periodontal ligament cells at 3 J/cm² under normal conditions, while photobiomodulation at 5 J/cm² upregulated the osteogenesis of periodontal ligament cells under starved and inflamed conditions. Conclusions: The photobiomodulation of 808 nm laser reduced inflammation and improved the proliferation, migration, and osteogenesis of normal, starved, and inflamed periodontal ligament cells. These effects required a higher energy density under starved or inflamed conditions compared with normal conditions. The photobiomodulation of 808 nm has a potential application in root surface treatment for replanted teeth.

Surface Modifications for Zirconia Dental Implants: A Review

Zirconia-based bioceramic is a potential material for dental implants developed and introduced in dentistry 30 years ago. However, some limitations still exist for zirconia implants caused by several factors, such as manufacturing difficulties, low-temperature degradation (LTD), long-term stability, and clinical experience. Several studies validated that some subtle changes on the zirconia surface might significantly impact its mechanical properties and osseointegration. Thus, attention was paid to the effect of surface modification of zirconia implants. This review generally summarizes the surface modifications of zirconia implants to date classified as physical treatment, chemical treatment, and surface coating, aiming to give an overall perspective based on the current situation. In conclusion, surface modification is an effective and essential method for zirconia implant application. However, before clinical use, we need more knowledge about these modification methods.

Evaluation of the bond strengths of restorative materials to primary tooth dentin treated with different pulpotomy techniques

The aim of this study was to investigate the changes of different pulpotomy techniques on the primary tooth dentin and to evaluate the effects of these pulpotomy methods on the shear bond strength of restorative materials to primary tooth dentin. Two hundred and forty dentin specimens were distributed randomly to the study groups as; control, ferric sulphate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma (APCP). After the application of pulpotomy methods, samples were again randomly divided to two restorative materials (glass hybrid and composite resin) (n = 20) and shear bond strength (SBS) test was performed. Then, 12 new dentin specimens were prepared for all groups for surface analysis. Surface examination (n = 12) and fracture analyses (n = 240) were carried out with scanning electron microscope (SEM). Statistical significance range was accepted as α <.05 for all data. A statistically significant difference was obtained among all study groups for glass hybrid material as well as composite material (p <.05). While the highest mean SBS value was obtained with Nd:YAG laser (7.58 ± 0.60 MPa), the lowest value was observed with Biodentine® (6.70 ± 0.91 MPa; p = .001) for glass hybrid material. For composite material, the highest mean SBS value was calculated for Nd:YAG laser (13.79 ± 1.24 MPa), while the lowest value was obtained with ferric sulphate (10.17 ± 1.45 MPa; p = .001). Fracture modes were mainly adhesive and mixed type according to SEM analysis. Moreover, morphological changes were observed with SEM on the dentin surfaces of ferric sulphate, Biodentine® and Nd:YAG laser. Within the limitations of this study, Nd:YAG laser increased the shear bond strength values in groups of composite resin. RESEARCH HIGHLIGHTS: In this article, we report the results of the shear bonding strength test of two restorative materials (glass-hybrid vs. composite resin) to primary tooth dentin following the application of five different pulpotomy techniques (ferric sulfate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma) were reported. This article will contribute to the literature that there are considerably limited researches concerning the bond strength of glass hybrid to primary dentin and also atmospheric pressure cold plasma in pulpotomies. The SEM examination was performed in two stages in this study; the morphological changes in both treated dentin surfaces and the surfaces of the samples subjected to the shear bond strength test.

Removal of Composite Restoration from the Root Surface in the Cervical Region Using Er: YAG Laser and Drill-In Vitro Study

Background: Recently, the defects of the tooth surface in the cervical region are often restored using composite filling materials. It should meet the needs of the patients regarding esthetics and material stability. The aim of the study was to analyze the tooth root surface at the cervical region after the removal of the composite filling material by means of the Erbium-doped Yttrium Aluminium Garnet (Er: YAG) laser or drill using the scanning electron microscopy (SEM) and fluorescence microscopy. Materials and Methods: For the purposes of this study, 14 premolar teeth (n = 14) were removed due to orthodontic reasons. The rectangular shape cavities with 3 mm in width and 1.5 mm in height were prepared with a 0.8 mm bur on high-speed contra-angle in the tooth surface just below cemento-enamel junction (CEJ) and filled with the composite material. The composite material was removed with the Er: YAG laser at a power of 3.4 W, energy 170 mJ, frequency 20 Hz, pulse duration 300 μs, tip diameter 0.8 mm, air/fluid cooling 3 mL/s, and time of irradiation: 6 sec, at a distance from teeth of 2 mm (G1 group, n = 7) or a high-speed contra-angle bur (G2 group, n = 7). After the removal of composite material, the surfaces of teeth were examined using the scanning electron microscopy (SEM) and fluorescence microscopy. Results: The Er: YAG irradiation allowed to remove completely the composite material from the tooth cavity. The study confirmed, that the ends of collagen fibers were only partially denatured after the Er: YAG laser application. Conclusion: It has been proved that using the Er: YAG laser is an effective and safe method of composite removal for the dentin surface.

[Advanced research on root canal therapy for primary teeth]

Primary tooth root canal therapy is a treatment performed on primary teeth diagnosed with pulpitis or periapical periodontitis. This procedure requires perfect instrumentation, disinfection, and filling of root canals to eliminate infection, control inflammation, relieve pain, prevent pathological effects on inherited permanent tooth, and prolong primary tooth preservation. This paper reviews the research history on primary tooth root canal treatment and summarizes the progress on primary tooth root canal treatment, including anatomical morphology, root canal preparation, root canal disinfection, root canal filling, and application of antibiotics.

Effect of Er:YAG laser irradiation on deciduous enamel roughness and bacterial adhesion: An in vitro study

Laser irradiation has been proposed as a preventive method against dental caries since it is capable to inhibit enamel demineralization by reducing carbonate and modifying organic matter, yet it can produce significant morphological changes. The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on superficial roughness of deciduous dental enamel and bacterial adhesion. Fifty-four samples of deciduous enamel were divided into three groups (n = 18 each). G1_control (nonirradiated); G2_100 (7.5 J/cm² ) and G3_100 (12.7 J/cm² ) were irradiated with Er:YAG laser at 7.5 and 12.7 J/cm² , respectively, under water irrigation. Surface roughness was measured before and after irradiation using a profilometer. Afterwards, six samples per group were used to measure bacterial growth by XTT cell viability assay. Adhered bacteria were observed using confocal laser scanning microscopy (CLSM) and a scanning electron microscopy (SEM). Paired t-, one-way analysis of variance (ANOVA), Kruskal-Wallis and pairwise Mann-Whitney U tests were performed to analyze statistical differences (p < .05). Before treatment, samples showed homogenous surface roughness, and after Er:YAG laser irradiation, the surfaces showed a significant increase in roughness values (p < .05). G3_100 (12.7 J/cm² ) showed the highest amount of Streptococcus mutans adhered (p < .05). The increase in the roughness of the tooth enamel surfaces was proportional to the energy density used; the increase in surface roughness caused by laser irradiation did not augment the adhesion of Streptococcus sanguinis; only the use of the energy density of 12.7 J/cm² favored significantly the adhesion of S. mutans.

Laser Techniques or Scalpel Incision for Labial Frenectomy: A Meta-analysis

Introduction

Labial frenectomy is a common procedure in the oral surgery specialty. Nowadays, laser surgery seems to provide better post-operative results than scalpel surgery. Thus, the aim of this study was to analyze whether trans-surgical and postoperative variables of labial frenectomy are better when performed with laser than with conventional scalpel.

Materials and Methods

A systematic review has been performed based on PRISMA criteria. The search included three databases, with no limitations of time or language. After screening, seven papers were included in qualitative analysis and six in meta-analysis. Bias analysis was performed according to Cochrane Handbook. Pain during the first (MD - 3.18, 95% CI - 4.03 to - 2.32) and seventh post-surgical days (MD - 1.04, 95% CI - 1.45 to - 0.64); discomfort during speech on the first (MD - 2.15, 95% CI - 3.94 to - 0.37) and the seventh post-surgical days (MD - 1.60, 95% CI - 1.96 to - 1.24); discomfort during chewing on the first (MD - 2.90, 95% CI - 3.35 to - 2.45) and the seventh days (MD - 1.56, 95% CI - 2.21 to - 0.91); and average surgery time (MD - 1.84, 95% CI - 3.22 to - 0.46) were lower in the laser group than in the scalpel group.

Conclusion

The results of this systematic review have shown better results to laser group in the following variables: pain, discomfort during speech and chewing. However, the evidence is limited due the high risk of bias.

Effect of Phototherapy on Masseter and Anterior Temporal Muscles Before Induction of Fatigue: A Randomized, Sham-Controlled, Blind Clinical Trial

OBJECTIVE

This is a randomized, sham-controlled, blind clinical trial that aimed to evaluate the effect of phototherapy on bite force, mandibular range of motion, sensitivity to palpation, and fatigue in the masseter and anterior temporal muscles of young patients when administered before the induction of fatigue.

MATERIALS AND METHODS

Fifty-two healthy volunteers aged 18-23 years were randomly allocated to a laser group and sham group. Both groups were submitted to a clinical evaluation to record mandibular range of motion, bite force, muscle sensitivity to palpation, and muscle fatigue. The laser group was then submitted to phototherapy (780 nm, 25 J/cm², 50 mW, 20 sec, and 1 J per point) on three points of the masseter and one point of the anterior temporal muscle on each side. The sham group was submitted to the same procedure, but with the device switched off. The volunteers were then instructed to chew two pieces of gum (one on each side) for 6 min, with the pace set by a metronome calibrated to 80 bpm, followed by the reevaluation of all variables. The results were submitted to t-test and Wilcoxon test. A significance level of 5% (p < 0.05) was considered in all analyses.

RESULTS

No statistically significant intergroup or intragroup differences were found for the variables analyzed.

CONCLUSIONS

With the proposed protocol, phototherapy administered before the induction of fatigue did not lead to any changes in bite force and mandibular range of motion, indicating that further studies are needed with different phototherapy dosimetric parameters.

Paediatric dentistry- novel evolvement

Pediatric dentistry provides primary and comprehensive preventive and therapeutic oral health care for infants and children through adolescence, together with special health care needs. This specialty encompasses a variety of skills, disciplines, procedures and techniques that share a common origin with other dental specialties however these have been modified and reformed to the distinctive requirements of infants, children, adolescents and special health care needs. Disciplines comprise of behavior guidance, care of the medically and developmentally compromised and disabled patient, supervision of orofacial growth and development, caries prevention, sedation, pharmacological management, and hospital dentistry including other traditional fields of dentistry. The skills apply to the ever-changing stages of dental, physical, and psychosocial development for treating conditions and diseases distinctive to growing individuals. Hence with the changing scope of practice it is imperative that the clinician stays updated with the current evidence based trends in practice, collaborates with other disciplines and Imparts quality oral health care tailored to the specific needs of every child.

Mid-Infrared Spectroscopy Analysis of the Effects of Erbium, Chromium:Yattrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) Laser Irradiation on Bone Mineral and Organic Components

The effects of varying the energy density of a high-intensity erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the mineral and organic components of bone tissue were evaluated using Fourier transform infrared spectroscopy. Bone samples obtained from the tibias of rabbits were irradiated with five energy densities (3, 6, 8, 12, and 15 J/cm(2)), and the effects on the carbonate to phosphate ratio and in the organic components were compared with those of nonirradiated samples. The increased temperature during the laser irradiation was also measured using infrared thermography to relate the observed spectral changes to the laser thermal effects. The analyses of the infrared spectra suggests that the irradiation with Er,Cr:YSGG promoted changes in bone tissue in both the mineral and organic components that depend on the laser energy density, pointing to the importance of using the proper energy density in clinical procedures.

Influence of the Nd:YAG laser pulse duration on the temperature of primary enamel

The aim of this study is to evaluate the temperature change on specimens of primary enamel irradiated with different pulse duration of Nd:YAG laser. Fifteen sound primary molars were sectioned mesiodistally, resulting in 30 specimens (3.5 × 3.5 × 2.0 mm). Two small holes were made on the dentin surface in which K-type thermocouples were installed to evaluate thermal changes. Specimens were randomly assigned in 3 groups (n = 10): A = EL (extra long pulse, 10.000 μs), B = LP (long pulse, 700 μs), and C = SP (short pulse, 350 μs). Nd:YAG laser (λ = 1.064 μm) was applied at contact mode (10 Hz, 0.8 W, 80 mJ) and energy density of 0.637 mJ/mm(2). Analysis of variance (ANOVA) was performed for the statistical analysis (P = 0.46). Nd:YAG laser pulse duration provided no difference on the temperature changes on primary enamel, in which the following means were observed: A = EL (23.15°C ± 7.75), B = LP (27.33°C ± 11.32), and C = SP (26.91°C ± 12.85). It can be concluded that the duration of the laser pulse Nd:YAG increased the temperature of the primary enamel but was not influenced by different pulse durations used in the irradiation.

Clinical and radiographic outcomes of the use of Low-Level Laser Therapy in vital pulp of primary teeth

AIM

This study aimed to compare the clinical and radiographic effectiveness of Low Level Laser Therapy in vital pulp of human primary teeth.

METHODS

Sixty mandibular primary molars of children aged between 5-9 years were assigned into four groups: Diluted Formocresol (FC), Calcium Hydroxide (CH), Low Level Laser Therapy (LLLT) and Calcium Hydroxide preceded by Low Level Laser Therapy (LLLT + CH). The clinical and radiographic evaluations were performed at 6, 12 and 18 post-operative months.

RESULTS

All the groups studied were successful in the clinical evaluation over the follow-up period. At 6 months, the radiographic success rate for FC group was 100%, 60% for CH group, 80% for LLLT group and 85.7% for LLLT + CH group. After 12 months, the radiographic success rate was 100% for FC group, 50% for CH group, 80% for LLLT group and 78.6% for LLLT + CH group. At the 18 months follow-up, 100% of the FC group, 66.7% of CH group, 73.3% of the LLLT group and 75% of the LLLT + CH group.

CONCLUSION

These findings suggest that Low Level Laser Therapy may be considered as an adjuvant alternative for vital pulp therapy on human primary teeth. Low Level Laser Therapy preceding the use of calcium hydroxide showed satisfactory results.

Effects of Er:YAG laser on mineral content of sound dentin in primary teeth

The aim of the present study was to evaluate the mineral content of sound dentin in primary teeth prepared using an Er:YAG laser at two different power settings. Thirty-six primary second molars were used in this study. Three dentin slabs were obtained from each tooth, and the slabs were randomly divided into three groups: Group A, control; Group B, Er:YAG laser at 3.5 W, 175 mJ, and 20 Hz, short pulse mode; and Group C, Er:YAG laser at 4 W, 200 mJ, and 20 Hz, medium-short pulse mode. One dentin slab per group was used to evaluate the dentinal morphology and surface roughness values using SEM and profilometer, respectively. Mineral content in the dentin slabs were calculated by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The data were analyzed by one-way analysis of variance and Tukey's HSD tests. No significant differences in Ca, K, Mg, Na, and P levels or Ca/P ratio were found among the groups (P > 0.05). SEM micrographs showed that surface irregularities increased with a higher power setting. The surface roughness after laser treatment in Group B and Group C was found to be similar, unlike Group A.

Effect of Nd:YAG laser pulse energy on mercury vapor release from the dental amalgam

OBJECTIVE

The aim of this study was to evaluate the effect of different pulse energies of Nd:YAG laser on the amalgam ablation, and its effect on the amount of mercury vapor release from amalgam.

BACKGROUND DATA

Toxic vapor release from amalgam restorations at the laser focus site is possible.

MATERIALS AND METHODS

Forty-five amalgam samples (4 mm in diameter and 5 mm in height) were placed in sealed containers and underwent Nd:YAG laser irradiation with pulse energies of 50, 150, and 250 mJ at a distance of 1 mm from the amalgam surface for 4 sec. Subsequently, 150 mL of air was collected from the inside of the container using an Apex Pump to analyze the amount of mercury vapor in the air samples using a mercury vapor analyzer. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests (p<0.05).

RESULTS

The amount of mercury vapor release significantly increased with an increase in the pulse energy of Nd:YAG laser (p<0.001). In addition, the amount of mercury vapor release with 250 mJ pulse energy was significantly higher compared with the standard mercury vapor concentration (50 μg/m(3)) (p<0.001). Nd:YAG laser produced cavities on the amalgam surface, which increased in size with an increase in the energy of the laser beam.

CONCLUSIONS

The amount of mercury vapor significantly increased with an increase in the pulse energy of the laser beam, and was significantly higher than the standard mercury vapor concentration with 250 mJ pulse energy.

Evaluation of effect of low-level laser therapy on adolescents with temporomandibular disorder: study protocol for a randomized controlled trial

Background

A number of problems involving the temporomandibular joint (TMJ) and associated structures can lead to temporomandibular disorder (TMD). The aim of the proposed study is to assess the effect of low-level laser therapy on occlusal contacts, mandibular movements, electromyography activity in the muscles of mastication and pain in adolescents with TMD.

Methods/Design

A randomized, controlled, double-blind, clinical trial will be carried out involving 85 male and female adolescents between 15 and 18 years of age. The research diagnostic criteria for TMD will be used to assess all individuals who agree to participate. All participants will be submitted to a clinical examination and electromyographic analysis of the masseter muscles and anterior bundle of the temporal muscles bilaterally, to determine TMD. Based on the clinical findings, the participants will be classified as having or not having TMD. Those with TMD will be divided into four groups, three of which will receive low-level laser therapy and one of which will receive a placebo treatment. The treatments will involve the TMJ region alone, the masseter and temporal muscles alone, or both these regions together. The data will be submitted to descriptive statistical analysis. The chi-square test and Fisher’s exact test will be used to determine associations among the categorical variables. The Student’s t test and analysis of variance will be used for the comparison of mean electromyographic signals. Pearson’s correlation coefficients will be calculated for the analysis of correlations among the continuous variables.

Trial registration

The protocol for this study has been submitted to Clinical Trials – registration number (NCT01846000).