Low-power pulsed Nd:YAG laser irradiation for pre-emptive anaesthesia: A morphological and histological study

Effect of Various Protocols of Pre-Emptive Pulpal Laser Analgesia on Enamel Surface Morphology Using Scanning Electron Microscopy: An Ex Vivo Study

Achieving local anaesthesia for various clinical dental applications is a challenge that we encounter in our daily practice. Pre-emptive pulpal laser analgesia (PPLA) treatment strategy could be a promising non-pharmacological modality. Hence, our ex vivo laboratory study is aimed at evaluating the changes in enamel surface morphology when irradiated with various published PPLA protocols using scanning electron microscopy (SEM). To do so, 24 extracted healthy human permanent premolar teeth were collected, and each tooth was divided into equal halves randomised into six groups. The following laser parameter protocols based on published protocols of clinical Er:YAG laser-induced PPLA were randomly assigned for each group: 0.2 W/10 Hz/3 J/cm2 (Group A—100% water spray; Group B—no water); 0.6 W/15 Hz/10 J/cm2 (Group C—100% water spray; Group D—no water); 0.75 W/15 Hz/12 J/cm2 (Group E—100% water spray; Group F—no water); 1 W/20 Hz/17 J/cm2 (Group G—100% water spray; Group H—no water). Each sample was irradiated at an angle of 90° to the dental pulp, with a sweeping speed of 2 mm/s for a 30 s exposure time. Our results have shown, for the first time, no alteration to the mineralised tooth structure when irradiated with the following protocols: 0.2 W/10 Hz/3 J/cm2 with 100% water spray or without water spray with an irradiated area fixed at a 10 mm tip-to-tissue distance, sweeping motion with 2 mm/s speed of movement; average power output of 0.6 W/15 Hz/10 J/cm2, maximum water cooling of 100%, tip-to-tooth distance fixed at 10 mm, 30 s exposure time, sweeping motion with 2 mm/s speed of movement. The authors concluded that the current available proposed PPLA protocols in the literature might cause an alteration to the enamel surface. Hence, future clinical studies are warranted to validate our study’s PPLA protocols.

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.

The 1064-nm Nd: YAG Photobiomodulation vs. 20% Benzocaine Topical Gel in Inducing Mucosal Anesthetic Effect: A Double-Blind Randomized Clinical Trial

The periapical local anesthetic injection may be associated with fear of needles and pain administration. Dental topical anesthetic agents can help to reduce pain perception; however, adverse events can occur. To investigate the efficacy of 1064-nm photobiomodualtion (PBM) in inducing mucosal anesthesia delivered with a flat-top hand-piece compared to 20% Benzocaine topical anesthetic gel, sixty healthy patients were randomly allocated (1:1) to either 20% benzocaine topical gel + placebo laser (T group) or PBM + placebo gel (L group). The 1064-nm Nd:YAG laser was employed and is associated with a novel flat-top hand piece. The applied operational parameters were 0.5 W, 10 Hz, 100 µs pulse width, and 30 J/cm2 for one-minute single application time. The enrolled subjects were asked to assess pain intensity at the time of anesthetic injection with a Visual Analog Scale. Taking into consideration taste, undesirable numbness, and overall satisfaction, the patients were asked to rate their experiences according to a verbal rating scale. Statistical analysis showed no statistically significant difference between the T and L Groups for pain ratings (p = 0.0596). The L Group displayed significantly higher ratings than T Group for taste, undesirable numbness, and overall satisfaction (p < 0.001). The 1064-nm PBM delivered by flat-top hand piece is effective in inducing mucosal anesthesia, eliminating the adverse side-effects of the conventional topical anesthetic gel.

Efficacy of erbium-doped yttrium aluminium garnet for achieving pre-emptive dental laser analgesia in children: A study protocol for a randomized clinical trial

INTRODUCTION

A current non-pharmacological mean for attaining painless conservative treatment is presented by laser analgesia (LA), considered as bio-photomodulation of pulp reactivity aiming reduction of nociceptive impulse formation. Currently no consensus is reached regarding a detailed protocol with laser parameter settings for pre-emptive LA. The purpose of this study is determining the efficacy of erbium-doped yttrium aluminium garnet (Er:YAG) laser in achieving pulpal analgesia and quantifying duration and extent of any effects assessed.

METHODS AND ANALYSIS

The proposed study is a double-blind placebo-controlled randomized split-mouth clinical trial with 2-way repeated measures design. Eligible patients of age 10 to 12 years undergo 2 single-visit treatments, receiving LA or placebo analgesia (PA) prior to caries ablation, randomized via computer-generated, permuted-block sequence. Primary outcome measure is pain felt during treatment, reported by patient on visual-analogue scale.

SECONDARY OUTCOMES

changes in pulpal sensibility to electrical and cold-stimuli; patient experience during LA/PA; pain-related behavior according to Faces, Legs, Activity, Cry, Consolabilty (FLACC) scale; heart-rate dynamics. Data will be analyzed with intention-to-treat concept by Student t test for paired samples, P < .05. Pre-test on 20 subjects resulted in n = 41 patients needing to be recruited.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Committee for Scientific Research Ethics, Medical University - Plovdiv, Bulgaria (Reference number P-8604, Protocol of approval N:6/23.11.2017) and registered on a publically accessible database. This research received institutional funding from the Medical University - Plovdiv, Bulgaria under project SPD-03/2017. Findings will be reported in scientific publications and at research conferences, and in project summary papers for participants.

TRIAL REGISTRATION

ClinicalTrials.gov (Registration number: NCT03412721).