Use of laser in orthodontics: applications and perspectives

Vibrational Force on Accelerating Orthodontic Tooth Movement: A Systematic Review and Meta-Analysis

This study aimed to systematically gather and analyze the current level of evidence for the effectiveness of the vibrational force in accelerating orthodontic tooth movement (OTM). This systematic review was conducted using three electronic databases: Scopus, PubMed, and Google Scholar until March 2022. The search was done through the following journals: European Journal of Orthodontics, American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, Progress in Orthodontics, and Seminars in Orthodontics. Human or animal studies that have evaluated the effect of vibrational force on the rate of OTM were selected. A meta-analysis was performed for the rate of canine movement per month. Database research, elimination of duplicate studies, data extraction, and risk of bias assessment were performed by authors independently and in duplication. A fixed and random-effect meta-analysis was performed to evaluate the effect of vibrational forces. A total of 19 studies (6 animal and 13 human studies) that met the inclusion criteria were included. Meta-analysis was performed based on four human clinical trials. Three out of four studies showed no significant difference in the rate of canine movement between vibrational force and control groups. The limitation of this study was the small sample size and significant heterogeneity among the studies. Although vibrational forces have been shown to accelerate OTM in experimental studies, the results are inconsistent in clinical studies. The inability to apply desired peak load to the targeted teeth may be the main factor in inconsistent clinical outcomes.

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.

Utilisation of an 810 nm diode laser for surgical management of oral soft tissues related to orthodontic treatment: A case series

The present case series demonstrates the efficacy of an 810 nm diode laser for the surgical management of oral soft tissues related to orthodontic treatment. Three orthodontic patients aged 16-23 years underwent operculectomy, ablation of soft-tissue overgrowth over orthodontic appliance and gingivectomy along with gingival recontouring procedures, respectively, using the 810 nm diode laser. In each case, an initiated laser fibre tip was utilised to ablate the tissue at the treatment site by making a light contact with the tissue (average power output = 1-1.6 W, continuous wave emission mode, fibre diameter = 400 µm, spot size = 0.0013 cm², energy density = 124.9-199.9 J/cm², irradiance = 796-1273 W/cm², total energy dose = 300-480 J). The maximum total length of treatment was 300 s (5 min). None of the patients reported any instantaneous or delayed postoperative complications over six months. Utilisation of the 810 nm diode laser for surgical management of oral soft tissues related to orthodontic treatments can be considered safe, effective and justifiable over the conventional scalpel technique; however, it must be performed by trained and experienced clinicians only.

The Effect of Erbium-Doped Yttrium Aluminum Garnet Laser in Debonding of Orthodontic Brackets: A Systematic Review of the Literature

Objective: The purpose of this review is to systematically assess the existing literature and summarize the evidence regarding the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser on enamel surface roughness and pulp health compared with the conventional orthodontic debonding techniques. Materials and methods: Following the preferred reporting items for systematic reviews (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement, the electronic database, PubMed, Scopus, Web of Science, Google scholar, and Saudi Digital Library were searched for relevant published records. Data were collected following specific keywords: "debonding" "Er:YAG laser" etc. In vitro studies, and clinical randomized- and nonrandomized-controlled studies limited to the English language and published in peer-reviewed journals were included. Results: A total of 564 articles were identified as relevant to the topic. Duplicates were excluded resulting in 382 articles, out of which 374 articles were discarded upon screening titles and abstracts. The remaining eight articles were read to their entirety and included in the current qualitative review after fulfilling the eligibility criteria. In all the included studies, a total of 480 sound posterior teeth were used to evaluate the effect of Er:YAG laser on debonding of orthodontic brackets from the enamel surface. Conclusions: Er:YAG laser debonding has demonstrated a reduced risk of enamel damage (fracture or cracks) but resulted in increased enamel surface roughness and was time-consuming for adhesive removal procedures compared with the conventional debonding methods. Further, within the applied laser settings, Er:YAG lasers have found to exhibit low thermal exhaustion in relation to the pulp. The laser source with a wavelength of 2940 nm has been used with different setting ranges (power of 2.5-5 W, energy 125-600 mJ, frequency 4-30 Hz, and pulse duration 50-350 μsec) for debonding of orthodontic brackets.

The effect of the local administration of biological substances on the rate of orthodontic tooth movement: a systematic review of human studies

BACKGROUND

The influence of different biological agents on the rate of orthodontic tooth movement (OTM) has been extensively reviewed in animal studies with conflicting results. These findings cannot be extrapolated from animals to humans. Therefore, we aimed to systematically investigate the most up-to-date available evidence of human studies regarding the effect of the administration of different biological substances on the rate of orthodontic tooth movement.

METHODS

A total of 8 databases were searched until the 16th of June 2020 without restrictions. Controlled randomized and non-randomized human clinical studies assessing the effect of biological substances on the rate of OTM were included. ROBINS-I and the Cochrane Risk of Bias tools were used. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 11 studies (6 randomized clinical trials and 5 prospective clinical trials) were identified for inclusion. Local injections of prostaglandin E1 and vitamin C exerted a positive influence on the rate of OTM; vitamin D showed variable effects. The use of platelet-rich plasma and its derivatives showed inconsistent results, while the local use of human relaxin hormone showed no significant effects on the rate of OTM.

LIMITATIONS

The limited and variable observation periods after the administration of the biological substances, the high and medium risk of bias assessment for some included studies, the variable concentrations of the assessed biological agents, the different experimental designs and teeth evaluated, and the variety of measurement tools have hampered the quantitative assessment of the results as originally planned.

CONCLUSIONS AND IMPLICATIONS

Despite the methodological limitations of the included studies, this systematic review provides an important overview of the effects of a variety of biological agents on the rate of tooth movement and elucidates the deficiencies in the clinical studies that have been conducted so far to evaluate the effectiveness of these agents in humans, providing some guidelines for future robust research.

TRIAL REGISTRATION

PROSPERO ( CRD42020168481 , www.crd.york.ac.uk/prospero ).

Application of the diode laser for soft-tissue surgery in orthodontics: Case series

Referral to an oral surgeon for soft-tissue surgery before, during or after orthodontic treatment is not uncommon. This process may delay treatment and could potentially increase the risk of complications. In addition, seeing multiple specialties in different environments may demotivate paediatric or anxious patients from pursuing orthodontic treatment and could also adversely affect patient compliance and satisfaction. The development of laser technology provides a safe and effective alternative, allowing the orthodontic clinician to perform soft-tissue surgery. To date, there are no laser exposure protocols or UK guidelines regarding the use of laser surgery in orthodontics. This case series reports four clinical cases that demonstrate potential advantages of using a diode laser for the management of soft tissue in the field of orthodontics.

Applications of Laser Welding in Dentistry: A State-of-the-Art Review

The dental industry without lasers is inconceivable right now. This captivating technology has outlasted other possible alternative technologies applied in dentistry in the past due to its precision, accuracy, minimal invasive effect as well as faster operating time. Other alternatives such as soldering, resistance (spot) welding, plasma (torch) welding, and single pulse tungsten inert gas welding have their pros and cons; nevertheless, laser welding remains the most suitable option so far for dental application. This paper attempts to give an insight into the laser principle and types of lasers used for dental purposes, types of dental alloys used by the dentist, and effect of laser parameters on prosthesis/implants. It is apparent from the literature review that laser assisted dental welding will continue to grow and will become an unparalleled technology for dental arena.

Can We Improve the Laser Etching with the Digitally Controlled Laser Handpiece-Xrunner?

OBJECTIVE

The aim of this study was to compare the shear bond strength (SBS), enamel surface characteristics, and the adhesive remnant index (ARI) scores of different etching methods.

BACKGROUND DATA

Laser etching changes the physical characteristics of the enamel surface and these alterations hold promise for the conditioning of enamel for bonding procedures. A new Er:YAG laser handpiece is unique in its ability to digitally control size, shape, and depth of irradiated enamel area.

MATERIALS AND METHODS

Ninety-eight premolar teeth were used in this study. Eighty of 98 teeth were divided into four experimental groups of 20 teeth each for SBS testing: (1) 37% phosphoric acid, (2) manual Er:YAG laser (120 mJ, 10 Hz, and 1.2 W), (3) manual Er,Cr:YSGG laser (45 mJ, 50 Hz, and 2.25 W), and (4) digitally controlled Er:YAG laser (Xrunner; 100 mJ, 10 Hz, 1 W). The SBS values and ARI scores were recorded. Eighteen teeth were used to evaluate the surface morphology with scanning electron microscopy and atomic force microscopy after etching and following debonding and restoration.

RESULTS

Mean SBS value was 7.75 ± 2.5 MPa for Xrunner and 8.11 ± 3.5, 9.47 ± 3.3, and 7.11 ± 3.7 MPa for the acid, Er,Cr:YSGG, and Er:YAG groups, respectively (p = 0.148). However, the acid etching group demonstrated significantly higher ARI scores (p < 0.001).

CONCLUSIONS

All etching methods caused enamel surface irregularities and were effectively restored to its original gloss. Laser etching was found to be an alternative to acid etching; however, the clinical success should be evaluated with further studies.

Histomorphometric assessment of the influence of low-level laser therapy on peri-implant tissue healing in the rabbit mandible

OBJECTIVE

The purpose of this study was to demonstrate the effect of low-level laser therapy (LLLT) on the peri-implant bone healing process in the rabbit mandible.

BACKGROUND DATA

LLLT has been shown to accelerate tissue repair and osseointegration of implants placed into the rabbit tibia. However, the beneficial effects of LLLT have never been tested in the rabbit mandible, which would more closely mimic the human situation.

MATERIALS AND METHODS

Twenty-four male New Zealand rabbits were randomly divided into four groups of six animals each. All animals had their left mandibular incisors extracted, followed by immediate insertion of a titanium dental implant in the fresh socket. Three groups received LLLT [aluminum-gallium-arsenide (AlGaAs), λ=830nm, 50 mW, continuous wave (CW)] at three different energy densities per treatment session (E-5, 5 J/cm(2); E-10, 10 J/cm(2); and E-20, 20 J/cm(2)). Irradiation was performed every 48 h for 13 days, totaling seven sessions. One group received sham treatment (controls). Histological sections were obtained from each of the 24 mandibles dissected, without first decalcifying the specimens, and were stained with hematoxylin and eosin and Picrosirius red for histomorphometric evaluation. Bone-to-implant contact (BIC), bone formation area, and collagen fiber area were assessed by light microscopy.

RESULTS

Significant differences were found between group E-20 and all other groups (p<0.05). Histomorphometric evaluation showed significantly higher BIC and significantly more collagen fibers in group E-20.

CONCLUSIONS

Photobiostimulation with LLLT at an energy density of 20 J/cm(2) per session had a significant positive effect on new bone formation around dental implants inserted in the rabbit mandible.

450 nm Blue Laser and Oral Surgery: Preliminary ex vivo Study

INTRODUCTION

Dental diode lasers were started to be used at the end of the 1990s and were shown to possess several important characteristics, such as small size and low cost, as well as the advantage of optic fibers delivering system. Although only two wavelengths (810 and 980 nm) had been the most used dental diode lasers, a wavelength emitting in the blue portion of the spectrum has recently been proposed.

AIM

The aim of this ex vivo study was to compare the effectiveness of five different fiber-delivered laser wavelengths (450, 532, 808, 1064, and 1340 nm) in the oral soft tissue ablation.

MATERIALS AND METHODS

Specimens were surgically collected from the dorsal surface of four bovine tongues and, while deep thermal increase was measured by two thermocouples at 0.5 and 2 mm depth, surface temperature was recorded by an infrared thermometer. Subsequently, specimens were fixed in 10% buffered formalin solution, cut into slices, and embedded in paraffin blocks, and a pathologist made a morphological analysis by optic microscope assigning a score based on the quality of the cut and tissue damage.

RESULTS

The analysis showed the best quality of the cut and the lowest temperature increase on the specimens obtained with the shortest laser wavelength (450 nm).

CONCLUSION

Even considering this as preliminary study, the use of 450 nm blue diode laser in oral surgery may be suggested to the clinician in their daily practice.

CLINICAL SIGNIFICANCE

This study opens a new perspective in oral surgery. Blue diode laser has demonstrated a good quality of the cut with a low energy causing a minimal thermal damage to the tissue, promising a better comfort to patients.

Four different diode lasers comparison on soft tissues surgery: a preliminary ex vivo study

Objectives: The introduction of diode lasers in dentistry had several advantages, principally consisting on the reduced size, reduced cost and possibility to beam delivering by optical fibbers. Up today only the wavelengths around 810 and 980 nm were the most utilized in oral surgery but recently more different lasers had been proposed. The aim of this study was to compare the efficacy of four diode laser wavelengths (810, 980, 1470 and 1950 nm) for the ablation of soft tissues. Material and methods: Specimens were surgically collected from the dorsal surface of four bovine tongues and irradiated by four different diode wavelengths. Thermal increase was measured by two thermocouples, the first at a depth of 0.5 mm, and the second at a depth of 2 mm. Initial and final surface temperatures were recorded by IR thermometer. Epithelial changes, connective tissue modifications, presence of vascular modification and incision morphology were histologically evaluated by two blind pathologists. Results: The time necessary to perform the excision varied between 271 seconds (808 nm, 2W) and 112 seconds (1950 nm, 4W). Temperature increase superficial level varied from 16.3° (980 nm, 4W) and 9.2° (1950 nm, 2 W). The most significant deep temperature increase was recorded by 980 nm, 4 W (17.3°) and the lowest by 1950 nm, 2 W (9.7°). The width of epithelial tissue injuries varied between 74 pm from 1950 nm diode laser at 2 W to 540 pm for 1470 nm diode laser at 4 W. Conclusion: The quality of incision was better and the width of overall tissue injuries was minor in the specimens obtained with higher wavelength (1950 nm) at lower power (2W).

Effect of femtosecond laser treatment on the shear bond strength of a metal bracket to prepared porcelain surface

OBJECTIVE

The aim of this study was to investigate the effects of femtosecond laser treatment (Group FS) on the shear bond strength (SBS) of a metal bracket to prepared porcelain surface, and to compare it with other surface treatment techniques [50 μm Al2O3 sandblasting (Group SB), 9.6% hydrofluoric acid gel (Group HF), and neodymium-doped yttrium aluminium garnet (Nd:YAG laser) (Group NY)].

BACKGROUND DATA

Because of the increasing number of adult patients in current orthodontic practice, achieving sufficient bond strength of composite resin to porcelain restorations without bond failure during the treatment is a challenge for orthodontists.

METHODS

In total, 80 glazed feldspathic porcelain samples were prepared and randomly assigned to four groups of 20. Treated surfaces were treated with a silane agent. Brackets were bonded to porcelain samples. The specimens were stored in distilled water for 24 h and then thermocycled for 500 cycles between 5° and 55°C. The SBS of the brackets was tested with a universal testing machine at a crosshead speed of 1 mm/min, until bonding failure occurred. The data were analyzed statistically using analysis of variance (ANOVA) and Tamhane multiple comparisons tests. The results of ANOVA indicated that the SBS values varied according to the surface treatment method (p<0.001).

RESULTS

Results of the Tamhane post-hoc tests indicated that the bond strength in Group NY (5.11±1.53) was significantly lower than the other groups (p<0.05). There were no statistically significant differences among Groups SB (9.07±3.76), HF (9.09±3.51), and FS (11.58±4.16) (p=0.28).

CONCLUSIONS

The results of this study showed that FS treatment produced high SBS of the processes assessed; therefore, it appears to be an effective method for bonding orthodontic metal brackets to prepared porcelain surfaces.