In vitro comparative study between adhesion forces obtained on zirconia ceramic micromechanically treated with femtosecond laser (1027 nm), carbon dioxide laser (10,600 nm), and aluminum-oxide particles.

Conventional surface roughening treatments used for silica-based ceramics in order to improve subsequent adhesion become unreliable for zirconia ceramics. Laser conditioning can be a good alternative. The purpose of this in vitro study was to compare conventional (macro) shear bond strength (SBS) values obtained between resin composite and zirconium oxide ceramic samples grouped according to different micromechanical treatments received, and examine differences in surface roughness. One-hundred and fifty disks of sintered zirconia were randomly divided into 5 groups and roughened as follows: (1) Group NOT, no surface treatment; (2) Group APA, abraded with 50-µm aluminum-oxide (Al2O3) particles; (3) Group TBS, abraded with 30-µm aluminum-oxide particles covered with silica; (4) Group CO2, irradiated with a CO2 laser which emitted in continuous wave mode at 3 W of power; and (5) Group FEM, irradiated with a pulsed femtosecond laser, with an incident energy of 10 µJ, a frequency of 1000 Hz, and a fluence of 1.3 kJ/cm2. All surfaces were treated with a MDP-containing adhesive/silane coupling agent mixture upon which were prepared and light polymerized composite resin cylinders. Shear bond strength was measured and samples were observed by scanning electron microscopy (SEM). Statistically significant differences (p < 0.05) were found among all groups, except between CO2 and FEM, which showed the highest adhesion values (15.12 ± 2.35 MPa and 16.03 ± 2.73 MPa). SEM revealed differences in surface patterns. CO2 laser irradiation can be an alternative to sandblasting, although it could also weaken the ceramic. Suitable surface patterns on zirconia ceramics can be obtained with ultrashort pulsed radiation emitted by a pulsed femtosecond laser.

Post-endodontic pain evaluation after different intracanal laser assisted disinfection techniques. A Systematic Review.

Background: Post-endodontic pain (PEP) management is an important factor to be considered in endodontic treatment. Several risk factors have been described that can attribute to its appearance. Laser-assisted disinfection has been described by many authors for its antimicrobial effect. Few studies described the relation between laser disinfection and its effect on PEP. The objective of this review is to describe the relation between different intracanal laser disinfection techniques and their effects on PEP. Material and Methods: An electronic search strategy was performed in Pubmed, Embase, and Web of Science (WOS) databases without restrictions as to the date of publication. Eligibility criteria were randomized controlled clinical trials (RCT) that used one of the different intracanal laser disinfection techniques in their experimental groups evaluating PEP outcome were included. Risk of bias analysis was performed by the Cochrane risk of bias tool. Results: The initial research identified 245 articles from which 221 were excluded and 21 studies were sought for retrieval and 12 articles met our inclusion criteria for the final qualitative analysis. The laser systems used were Nd:YAG, Er:YAG and, diode lasers including photodynamic therapy. Conclusions: The diode lasers showed the most promising results in terms of PEP reduction while Er:YAG showed more short-term efficacy (6 hours postoperative interval). The variables could not be analyzed homogenously due to the differences in the study designs. More RCT are needed comparing different laser disinfection techniques with the same baseline endodontic pathology to establish a specific protocol for the best outcome. Key words:Root canal treatment, Post-endodontic pain, Intracanal laser disinfection, laser dentistry.

Comparative Study of Transmission of 2940 nm Wavelength in Six Different Aesthetic Orthodontic Brackets.

BACKGROUND: Previous studies have confirmed the superiority of using erbium lasers (2940, 2780 nm) over other lasers in the debonding of ceramic brackets due to their safety and effectiveness. The most important factor in the debonding of aesthetic brackets is the transmission of the erbium laser through the aesthetic bracket to the adhesive resin. OBJECTIVE: To identify the transmission of the 2940 nm wavelength through different types of aesthetic brackets. MATERIALS AND METHODS: A total of 60 aesthetic brackets were divided into six equal groups (10 monocrystalline sapphire brackets-Radiance, AO; 10 monocrystalline sapphire brackets-Absolute, Star Dentech; 10 polycrystalline brackets-20/40, AO; 10 polycrystalline brackets-3M Unitek Gemini Clear Ceramic; 10 silicon brackets-Silkon Plus, AO; 10 composite brackets-Orthoflex, OrthoTech). The aesthetic brackets were mounted in a Fourier transform infrared spectrophotometer (FTIR IRPrestige-21, SHIMADZU) following the typical spectroscopy lab procedure for such samples. The transmission ratio for the 2940 nm wavelength was obtained using IRsolution software. The mean transmission values of the tested groups were compared using a one-way analysis of variance (ANOVA) test followed by a Bonferroni test (post-hoc test). RESULTS: The highest transmission ratio was observed for the Radiance sapphire brackets (64.75%) and the lowest was observed for the 3M polycrystalline brackets (40.48%). The differences among the Aesthetic brackets were significant (p < 0.05). CONCLUSIONS: The thick polycrystalline and composite brackets have the lowest transmissibility, whereas the monocrystalline sapphire brackets have the highest transmissibility for the 2940 nm wavelength, meaning that there is a higher possibility of debonding them with a hard tissue laser through thermal ablation.

Parameters Used With Diode Lasers (808-980 nm) in Dentin Hypersensitivity Management: A Systematic Review.

Introduction: The present study aimed to describe parameters used with 808- to 980-nm wavelength diode lasers for managing dentin hypersensitivity and analyze their results. Methods: The inclusion criteria were based on randomized controlled clinical trials using diode lasers at an 808-980 nm wavelength range in patients with dentine hypersensitivity with a minimum of 1-month follow-up. An electronic search for articles on Medline, PubMed and Cochrane databases was performed. The risk of bias was assessed with the Cochrane collaboration tool. Results: Our electronic search resulted in 130 papers, of which 11 articles met the inclusion criteria. A majority of the studies assessed dentine hypersensitivity using the Visual Analogue Scale, which ranged between 2.3 and 8.8 before treatment and significantly reduced to a mean value of 0.45-3.7 after diode laser application. The power settings ranged between 1.5 mW and 3 W with an emission mode of continuous wave, except for 2 authors who used chopped mode. The energy density varied from 2.5 to 128 J/cm2, and the exposure time was between 10 and 120 seconds. The authors applied a minimum of 1 to 4 treatment sessions with a 2-day to 1-week interval between them. Most of the studies mentioned the tooth surface as the treatment site but without describing the specific irradiation points. Conclusion: Despite the heterogeneity of the analyzed variables, a statistically significant improvement in all laser groups was described. However, they cannot be compared homogenously.

Photobiomodulation therapy and endodontic treatment of teeth with apical periodontitis using 940-nm diode laser. Report of two cases.

Background: Diode laser (DL) can be used in endodontics both for its bactericidal effect inside the root canal system (RCS) and for photobiomodulation therapy (PBMT) to accelerate the repair of periradicular bone tissue. Clinical Cases: This work presents two cases of pulp necrosis/asymptomatic apical periodontitis (AAP) that were treated with 940-nm DL, administered both to disinfect the root canal and to apply PBMT to the periradicular tissues. The cases were analysed by Cone-Beam Computed Tomography (CBCT). Discussion: DL has become widely accepted due to its high antimicrobial effectiveness and its ability to accelerate the repair of large apical lesions by biostimulation. Nevertheless, differences of opinion persist within the scientific community due to the lack of standardized endodontic protocols. Conclusions: The application of 940-nm DL, both for disinfection of the RCS and for PBMT, is an effective treatment in non-vital teeth with large periapical lesions. In both cases reported, bone neoformation were found at the 6-month check-up. Key words:Low-level laser therapy, photobiomodulation therapy, diode laser, endodontics.

Laser-Assisted Esthetic Crown Lengthening: Open-Flap Versus Flapless.

This study compares the clinical outcomes of Er,Cr:YSGG (2,780 nm) laser-assisted open-flap (OF) and flapless (FL) esthetic crown lengthening (ECL) for the treatment of altered passive eruption. Thirty-six healthy patients requiring ECL were randomly divided into two groups: OF and FL. Gingivectomy and ostectomy were performed with an Er,Cr:YSGG laser in both groups. The periodontal condition and gingival margin level (GML) were assessed at baseline, immediately postsurgery, and at 1, 3, and 9 months postsurgery. The effect of periodontal phenotype and tooth location on GML and supracrestal gingival tissue dimension were evaluated. A significant difference was detected in the mean of GML at all time points, except between 3 and 9 months. The main tissue rebound after 9 months was 0.25 ± 0.3 mm in the OF group and 0.26 ± 0.3 mm in the FL group (no significant difference) and was significantly higher in thick periodontal phenotypes. Er,Cr:YSGG laser-assisted ECL is a predictable technique that achieved similar outcomes using flap and flapless approaches, providing esthetic and restorative opportunities for clinicians.

Photodynamic Therapy in Endodontics: A Helpful Tool to Combat Antibiotic Resistance? A Literature Review.

BACKGROUND: Antibiotic resistance has become a growing global problem where overprescription is a contributing factor for its development. In the endodontics field, complementary treatments, such as antimicrobial photodynamic therapy (aPDT), have been described to eliminate residual bacteria from the root canal space and reduce complications. The aim of this review is to describe the literature evidence up to now regarding the advantages, efficiency, and clinical outcomes of this therapy in endodontics as a possible tool to combat antibiotic resistance. METHODS: A review of the literature from 2010 to 2021 was carried out using the PubMed and Web of Science databases. Two steps were taken: First, articles were compiled through the terms and MeSH terms "Photochesdmotherapy" and "endodontics." Then, a second search was conducted using "photodynamic therapy" and "antibiotic resistance" or "drug resistance, microbial." RESULTS: A total of 51 articles were included for evaluation: 27 laboratory studies, 14 reviews, and 10 clinical studies. Laboratory studies show that aPDT achieves significant bacterial elimination, even against antibiotic-resistant species, and is also effective in biofilm disruption. Clinical studies suggest that aPDT can be considered a promising technique to reduce bacterial complications, and reviews about the issue confirm its advantages. CONCLUSION: The benefits of aPDT in reducing complications due to its antibacterial effects means a possible decrease in systemic antibiotic prescription in endodontics. In addition, it could be an alternative to local intracanal antibiotic therapy, avoiding the appearance of possible antibiotic resistance, as no bacterial resistance with aPDT has been described to date.

Irrigación Activada por Láser en Endodoncia

RESUMEN: El objetivo de la endodoncia es prevenir o curar la periodontitis apical. Por lo tanto, los microorganismos que han colonizado el sistema de canales radiculares deben ser eliminados para promover la regeneración y cicatrización. Desafortunadamente, la existencia de canales accesorios, anastomosis, istmos, así como ramificaciones apicales, genera una compleja red tridimensional en el interior de la raíz, lo que dificulta la eliminación total de bacterias y detritus. La te rapia endodóntica convencional utilizada actualmente presenta una serie de limitaciones.Se ha demostrado que los instrumentos endodónticos dejan un 35 % o más de superficie dentinaria sin tratar. Por otro lado, la imposibilidad de generar un flujo turbulento en el interior de los canales, impide que el irrigante llegue a zonas de difícil acceso. Esto facilita la persistenc ia de biopelículas bacterianas y la supervivencia de un número importante de bacterias viables. La irrigación activada por láser (LAI) ha sido propuesta como una tecnología co-adyuvante a la terapia quimio-mecánica para optimizarla limpieza y desinfección. Los láseresde Er,Cr:YSGG (2780nm) y Er:YAG (2940nm) son los más utilizados. Estas dos longitudes de onda son capaces de ser absorbidas ampliamente por diferentes soluciones irrigantes, teniendo en cuenta un uso seguro y respetando los parámetros clínicos aceptados. La absorción de la energía del láser por parte de los irrigantes, genera burbujas de vapor en el interior del fluido, que liberan fuerzas de cizalla al implosionar. Este fenómeno, denominado cavitación, genera mayor limpieza y desinfección del interior del sistema de canales radiculares, incluso en zonas de difícil acceso. Diversos estudios microbiológicos y microscópicos, han demostrado la efectividad antibacteriana de LAI. Recientemente, se ha publicado que LAI tendría la capacidad de incrementarla capacidad antibacteriana del hipoclorito de sodio a baja concentración (un buen desinfectante pero extraordinariamente tóxico), lo que permitiría trabajar con concentraciones menores y por lo tanto más seguras para el paciente.

ABSTRACT: The goal of endodontics is to prevent or cure apical periodontitis. Therefore, microorganisms that have colonized the root canal system must be eliminated to promote regeneration and healing. Unfortunately, the existence of accessory canals, anastomoses, isthmus, as well as apical ramifications, form a complex three-dimensional network inside the root, which makes difficult the total elimination of bacteria and detritus. Conventional endodontic therapy has several limitations. Endodontic instruments have been shown to leave 35 % or more of the dentin surface untreated. On the other hand, the inability of generating a turbulent flow, prevents the irrigant from reaching areas that are difficult to access. This facilitates the persistence of bacterial biofilms and the survival of a significant number of viable bacteria. Laser-activated Irrigation (LAI) has been proposed as a co-adjuvant to chemo-mechanical therapy to improve cleaning and disinfection. Er, Cr: YSGG (2780nm) and Er: YAG (2940nm) lasers are the most widely used. These two wavelengths are capable of being widely absorbed by different irrigating solutions, taking into account safe use and respecting accepted clinical parameters.The deep absorption of laser energy generates steam bubbles inside the fluid, which release shear forces when imploding. This phenomenon, called cavitation, is responsible for greater cleaning and disinfection within the root canal system, even in areas difficult to access. Several studies have demonstrated the antibacterial effectiveness of LAI through microbiological methods and microscopic techniques. Recently, it has been reported that LAI would have the ability to increase the antibacterial capacity of low concentration of sodium hypochlorite (a good disinfectant but extremely toxic), which would allow working with concentrations that are safer for the patient.

Laser dentistry in daily practice during the COVID-19 pandemic: Benefits, risks and recommendations for safe treatments.

The COVID-19 pandemic forced dental professionals to cope with an unexpected challenge and caused an abrupt cessation of conventional care practices. The high degree of contagiousness as well as the diffusion of the virus through the air and droplets via respiratory transmission placed dental professionals at top-level risk of contracting and spreading the disease. General recommendations were announced in different countries, including patient distancing, air ventilation, surface and instrument sanitization, and the wearing of suitable masks and shields. However, many dental treatments are performed using lasers, and some specific precautions must be added to conventional procedures to ensure the advantages of this technology to patients because of the particular tissue­matter interaction effects of laser wavelengths. Based on the literature, the authors evaluated all of using laser wavelengths to analyze the risk and the benefits of using lasers in daily dental practice, and to provide safety recommendations during pandemic. An unrestricted search of indexed databases was performed. Laser use effects were categorized into: 1) explosive processes that produce tissue ablation and aerosol formation; 2) thermal actions that create vaporization and smoke plume; 3) photobiomodulation of the cells; and 4) enhanced chemical activity. Knowledge of the device functions and choice of adequate parameters will reduce aerosol and plume formation, and the application of suction systems with high flow volume and good filtration close to the surgical site will avoid virus dissemination during laser use. In the categories that involve low energy, the beneficial effects of lasers are available and sometimes preferable during this pandemic because only conventional precautions are required. Lasers maintain the potential to add benefits to dental practice even in the COVID-19 era, but it is necessary to know how lasers work to utilize these advantages. The great potential of laser light, with undiscovered limits, may provide a different path to face the severe health challenges of this pandemic.

Success Rate of Benign Oral Squamous Papilloma Treatments After Different Surgical Protocols (Conventional, Nd:YAG, CO2 and Diode 980 nm Lasers): A 34-Year Retrospective Study.

Objective: The aim of our retrospective study is to compare the long-term recurrence rate of the benign oral squamous papilloma (OSP) with different laser-assisted treatments and conventional procedures (use of scalpels) aiming to suggest the most suitable surgical protocol showing the lowest recurrence rate. Background: A retrospective multicenter DATA collection between 1985 and 2019 covering 781 OSP cases concerning different surgical protocols used for the treatment of OSP was done and included the use of different laser wavelengths [neodymium-doped yttrium-aluminum-garnet (Nd:YAG), carbon dioxide (CO2), and Diode 980 nm] and the conventional surgeries using the scalpel. The age, sex, and the oral location of the OSP were noted. Methods: Three different surgical protocols were selected in our study: protocol 1 regrouped surgical procedures performing the excision of OSP with an in-depth safety margin of 1 mm and just at the base of the tumor with reduced excision of the grossly normal marginal mucosa around the tumor (0-1 mm). Protocol 2 and 3 were similar to protocol 1, but with an additional excision of 1-2 mm and ≥3 mm of the grossly normal marginal mucosa, respectively, for group 2 and 3. All laser-treated OSP wounds were left without sutures. In the conventionally treated OSP, sutures were regularly performed. Follow-up was done after 15 days and at 1, 6, and 18 months. The three included wavelengths were Nd:YAG (1064 nm), CO2 laser (10,600 nm), and diode laser (980 nm). Results: After 18 months of follow-up, the highest success rate was obtained with protocol 3 (100% with Nd:YAG, 99% with CO2, 98.4% with diode, and 99% with the scalpel), which was significantly higher than the values of protocol 2 (96.6% with Nd:YAG, 91% with CO2, 96% with diode, and 95% with the scalpel) and the protocol 1 (38% with Nd:YAG, 29% with CO2, 33% with diode, and 30% with the scalpel). The oral locations of OSP were 30% on palates, 30% on the tongue, 16% on cheek, 14% on lips, and 10% on other locations. Conclusions: The lowest recurrence rate was observed when a minimum of three millimeters (≥3 mm) of grossly normal aspect mucosa around the OSP was included in the excisions. The laser wavelengths and the use of scalpel did not show any significant difference in terms of recurrence.

Aerosols generation using Er,Cr:YSGG laser compared to rotary instruments in conservative dentistry: A preliminary study.

BACKGROUND: In restorative dentistry, the use of high-speed air turbine, which generates aerosols, can be associated with the transmission of airborne diseases. New laser technologies could be useful in reducing the amount of aerosols, but there is a lack of scientific research on this topic. MATERIAL AND METHODS: This is a descriptive study to analyze the amount of aerosols produced after class I cavity preparation using high-speed air turbine (group 1) and Er,Cr:YSGG laser with two different parameters (groups 2 and 3). Fluorescein dye was incorporated into the coolant reservoir in order to visualize the production of aerosols during each procedure. Tooth preparation was performed in a typodont with human lower molar tooth under rubber dam isolation. The procedure was carried out in a transparent plastic box to avoid aerosols dispersion. Sixteen grade I cellulose filter discs were distributed along the surfaces of the box. The area contaminated with aerosols in the filters was measured using ultraviolet illumination. RESULTS: In group 1, the contaminated surface area covered with fluorescein dye reached 77.3% (1349 cm2) of the total; in group 2 (laser with 80% water) we observed 7.3% (128 cm2) and in group 3 (laser with 40% water) it was 3.8% (68 cm2). The reduction in water parameter from 80% to 40% coincided with 48% reduction of the contaminated area on the filter discs. Focusing on the surfaces of the box, we noted that the mean contamination on the left side was more than on the right side in all three experimental groups. In group 1 using air turbine, we measured a mean of 102.6[±7.5 SD]cm2 on the left side, compared to 70.6[±32.3 SD]cm2 on the right side. In laser groups 2 and 3, a mean of 12.8[±14.9 SD]cm2 and 6.8 [±5.7SD]cm2, respectively, was described on the left surface versus 0 cm2 of surface contamination on the right surface. CONCLUSIONS: The contaminated area during the procedure of class I cavity preparation, is reduced by 70% using Er,Cr:YSGG laser compared to high-speed turbine. A slightly higher contamination was observed between laser groups with 80% versus 40% water. The use of Er,Cr:YSGG laser in restorative dentistry can be a valid treatment alternative to reduce aerosols production compared to conventional high-speed rotary instruments. Key words:Er,Cr:YSGG laser, Aerosols, SARS-CoV-2, Rotary instruments, conservative dentistry.

Effect of Photobiomodulation (Diode 810 nm) on Long-Standing Neurosensory Alterations of the Inferior Alveolar Nerve: A Case Series Study.

Objective: To evaluate and describe the results of photobiomodulation (PBM) therapy on the treatment of long-standing neurosensory inferior alveolar nerve (IAN) alterations after third molar extraction. Background: The use of PBM is an acceptable alternative method to improve the therapeutic outcomes of neural lesions. Materials and methods: Longitudinal case study research. Patients with >6 months of inferior alveolar neurosensory disturbance after third molar extraction were included. Fifteen laser sessions were done, irradiating intra- and extraoral points along the distribution of this nerve area. A semiconductor Ga,Al,As diode laser (Thor laser®) was used. Before and after the treatment, variables such as Zuniga-Essick score, British Medical Research Council (BRC) scale, visual analog scale (VAS), and mapping of the affected area were described. Gender, age, and duration of the lesion were analyzed. Descriptive statistical study was carried out with SPSS 19.0. Results: Eleven patients with a mean age of 38.5 years [standard deviation (SD) ±15.22]. Average duration of the lesion was 13.2 (SD ±4) months. The results obtained with the Zuniga-Essick scale before treatment showed mild alteration in 36.3% (4), moderate in 18.2% (2), and severe in 45.4% (5). After treatment, the percentage score improved, obtaining normality in 54.5% (6) of the patients and mild degree in 27.2% (3). In the BRC score, before the treatment, 45.4% (5) of grade S2+ and 27% (3) of S3 and S3+ were obtained. The final percentage after treatment reached an improvement of S4 in a total of 36% (4) of cases and a recovery of S3+ in 54.5% (6). Reduction of the mapped altered area and an upturn of VAS were noted. Conclusions: The laser parameters and application protocol used result in subjective and objective improvement in mechanical sensory perception in long-standing neurosensory deficit in the IAN.

Aesthetic Treatment Outcomes of Capillary Hemangioma, Venous Lake, and Venous Malformation of the Lip Using Different Surgical Procedures and Laser Wavelengths (Nd:YAG, Er,Cr:YSGG, CO2, and Diode 980 nm).

Different approaches with different clinical outcomes have been found in treating capillary hemangioma (CH), venous lake (VL), or venous malformations (VM) of the lips. This retrospective study aims to assess scar quality, recurrence rate, and patient satisfaction after different surgeries with different laser wavelengths. A total of 143 patients with CH or VM were included. Nd:YAG laser was used for 47 patients, diode 980 nm laser was used for 32 patients (treatments by transmucosal photo-thermo-coagulation), Er,Cr:YSSG laser was used for 12 patients (treatments by excision), and CO2 laser was used for 52 patients (treatments by photo-vaporization). The Manchester scar scale was used by practitioners to assess the scar quality. The recurrence rate and patients' satisfaction were noted at different follow-ups during 12 months. Our retrospective study showed that laser-assisted aesthetic treatment of vascular lesions (CH, VL, and VM) of the lips can be considered effective regardless of the wavelength used (Er,Cr:YSGG, CO2, Nd:YAG, and diode 980 nm) or the treatment procedure (transmucosal photo-thermo-coagulation, photo-vaporization, and surgical excision). There was no significant difference in patient and practitioner satisfaction with aesthetic outcome at 6 months follow-up. Furthermore, the treatments of lip vascular lesions performed using Er,Cr:YSGG and CO2 lasers did not show any recurrence during the 12 months of follow-up, while recurrence rates of 11% ± 1.4% and 8% ± 0.9% were seen in the diode and Nd:YAG groups, respectively.

A randomized split-mouth clinical trial comparing pain experienced during palatal injections with two different computer-controlled local anesthetic delivery systems.

BACKGROUND: Several methods have been proposed to reduce pain during injection. The main aim to this study was to compare the pain perception in patients receiving palatal injections of local anesthesia using two different computer-controlled local anesthetic delivery systems (C-CLAD) - Dentapen® and The STA Wand®). MATERIAL AND METHODS: A randomized, split-mouth and simple blind clinical trial was carried out at the Dental Hospital of the University of Barcelona (Spain) involving a sample of 20 healthy volunteers. Each participant received two palatal injections in the same session (0.3 ml of 3% mepivacaine without vasoconstrictor), using The STA Wand® on one side and the Dentapen® on the contralateral side. The order of the devices and the side of the injections were randomly selected. Pain perception was recorded after each injection using a 10-cm numeric rating scale (NRS). A descriptive and bivariate analysis of the data was performed. RESULTS: Pain perception was similar with both devices (p>0.05). The STA Wand® and Dentapen® groups yielded a mean pain score of 2.40 cm (standard deviation (SD) = 1.47, range 0-6) and 2.35 cm (SD 1.3, range 1-6), respectively. Most participants referred mild pain (80%), and none experienced severe pain. There were no adverse events. CONCLUSIONS: In the majority of cases (80%), both C-CLAD devices allow the administration of local anesthetics in the palatal area with mild pain. Both The STA Wand® and Dentapen® are equally effective in reducing pain perception levels for palatal injections. Key words:Computer-controlled local anesthetic delivery, dental anesthesia; palatal anesthesia, The STA Wand, Dentapen.

Effect of an Er,Cr:YSGG Laser on the Surface of Implants: A Descriptive Comparative Study of 3 Different Tips and Pulse Energies.

Peri-implant diseases are one of the main complications of dental implants. There are no well-established guidelines regarding laser parameters for implant decontamination. The aim was to compare two different settings of irradiation of the Er,Cr:YSGG laser on dental implants regarding surface alterations and determine the best settings for less damage on the surface. An in vitro study was performed and 30 areas of dental implants were irradiated with two different regimes of energy per pulse 50 and 84 mJ (1.5 W/30 Hz and 2.5 W/30 Hz). A total of 30 sites of implants were irradiated with three different tips (10 surfaces per tip): conical (RTF3-17 mm), side firing (SFT8-18 mm) and cylindrical (MGG6-6 mm). The following descriptive classification on surface damage was employed: no damage (class A), minimal effects (class B), metal fall with melting (class C), and destruction with carbonization (class D). The assessment was made through a descriptive scanning electron microscope (SEM) analysis. Side firing and conical tips at 50 mJ were classified as class A. Side firing at 84 mJ and cylindrical tips 50 mJ and 84 mJ were classified as class B. Finally, class C defects were found in the areas where the conical tip was used at 84 mJ. Side firing and conical tips at 50 mJ do not seem to damage the implant surface.

Er,Cr:YSGG Laser in the Debonding of Feldspathic Porcelain Veneers: An In Vitro Study of Two Different Fluences.

Background: New applications in laser technology in aesthetic restorative dentistry merit further research. This study compares the debonding strength and failure mode of feldspathic ceramic veneers using either Er,Cr:YSGG (erbium,chromium:ytrrium-scandium-gallium-garnet) laser at two levels of fluency or no laser (control group). Methods: An in vitro comparative study was carried out using bovine teeth that were randomly distributed into 3 groups of 21 specimens each: (a) experimental group 1 (EG1): irradiated with Er,Cr:YSGG (Waterlase iPlus®; Biolase, Irvine) at an energy density per pulse of 4 J/cm2, using a handpiece (Turbo; Biolase) with a sapphire tip (MX7) and applying the beam perpendicular to the specimen at a distance of 4 mm for 60 sec; (b) experimental group 2 (EG2): irradiated as in EG1, but at 2.7 J/cm2; and (c) control group (CG): debonding without laser irradiation. Results: The stress required for veneer debonding was 8.19 MPa in CG, 0.91 MPa in EG1, and 0.48 MPa in EG2. The difference between the control and both experimental groups was statistically significant (p < 0.001). The percentages of adhesive failure were 40%, 61.9%, and 96%, respectively. Conclusions: Using the Er,Cr:YSGG laser at 4 or 2.7 J/cm2 requires significantly less force to debond ceramic veneers. The percentage of adhesive failures in the two experimental protocols was higher than in the control group. Application of the Er,Cr:YSGG laser using the parameters in this study may be useful in removing feldspathic ceramic veneers, avoiding damaging them and protecting the enamel.

Evaluation of student-to-student local anaesthesia administration at the University of Barcelona: A cross-sectional study.

INTRODUCTION: To determine changes in anxiety perceived in students during their first experience injecting local anaesthetic and assess the variability in the perception in the teaching/learning experience as surgeons and patients in relation to gender. MATERIAL AND METHODS: This cross-sectional study was carried out on students enrolled in the Anaesthesia and Resuscitation course at the University of Barcelona. A descriptive and bivariate analysis was carried out using McNemar and Fisher tests. The level of significance was set at a P-value of <.05. RESULTS: Out of 85 students, a total of 71 responses were obtained. Overall, significant anxiety changes associated with the inferior alveolar nerve block were observed, specifically, before and during (P = .003), before and after (P < .001), and during and after (P < .001) the injection. The calm/relaxed category showed significant differences between before and after (P < .001) and during and after (P < .001) the procedure. Opinions and responses from male and female students differed statistically in relation to the injection on each other as preparation for real work situations (P < .023), recognition of landmarks (P < .001), determination of the insertion points (P = .032) and the need for supervision (P = .043). CONCLUSIONS: This study showed that the overall, students felt more anxious before being injecting with the anaesthetic and the students learning to give the local anaesthetic to each other is an appropriate learning method. No gender-related differences were observed in the participants.

Er,Cr:YSGG Laser-Activated Irrigation and Passive Ultrasonic Irrigation: Comparison of Two Strategies for Root Canal Disinfection.

Objective: To compare the antibacterial effectiveness of 0.5% sodium hypochlorite (NaOCl) activated by the Er,Cr:YSGG laser-activated irrigation (LAI) and passive ultrasonic irrigation (PUI) against a 10-day-old intracanal Enterococcus faecalis biofilm. Background: LAI and PUI are regarded as alternative methods to release the irrigant in the inner regions of the root canal system achieving enhanced cleaning ability. Nevertheless, little evidence regarding the activation of low concentrations of NaOCl has been reported. Materials and methods: Seventy-two single-rooted teeth were instrumented, inoculated (E. faecalis ATCC 29212), and incubated for 10 days to allow biofilm formation. Specimens were randomly divided into six groups (n = 12 each): (1) 0.5% NaOCl+Er,Cr:YSGG LAI, (2) saline+Er,Cr:YSGG LAI, (3) 0.5% NaOCl+PUI, (4) saline+PUI, (5) positive control (no treatment), and (6) negative control (no bacteria). The activation time was distributed as follows: 30 sec of activation, followed by a rest phase of 30 sec, and ending with 30 sec of activation. The number of bacterial survivors was determined by plate counting. Results: Both irrigation regimens LAI and PUI reduced the number of colony-forming unit. Moreover, LAI +0.5% NaOCl and the rest of groups significantly differ (p < 0.001 for all comparisons). Conclusions: Er,Cr:YSGG LAI proved to be more effective than PUI in enhancing the antimicrobial activity of 0.5% NaOCl against 10-day-old intracanal E. faecalis biofilms.

Er,Cr:YSGG Laser-Activation Enhances Antimicrobial and Antibiofilm Action of Low Concentrations of Sodium Hypochlorite in Root Canals.

The onset and persistence of endodontic infections due to residual biofilm after chemical disinfection promotes secondary bacterial infection. Alternative methods to disinfect operated root canals are a matter of great interest. The aim was to evaluate the antibacterial effectiveness of sodium hypochlorite (NaOCl) at low concentrations activated by the Er,Cr:YSGG laser-activated irrigation (LAI) against 10-day-old intracanal Enterococcus faecalis biofilm. Biofilms were formed inside the root canals and divided into 7 groups (n13): 0.5% NaOCl + Er,Cr:YSGG; Saline + Er,Cr:YSGG; 0.5% NaOCl + syringe irrigation(SI); 2.5% NaOCl + SI; 5% NaOCl + SI; positive and negative controls. Bacterial survivors were counted and specimens visualized under scanning electron and confocal laser scanning microscopy. Treatments with 0.5% NaOCl + Er,Cr:YSGG and 2.5% NaOCl + SI gave a significant reduction in the number of CFU/mm2. Moreover, scanning electron microscopy and confocal laser scanning microscopy imaging confirmed and reinforced bacteriological data. Thus, Er,Cr:YSGG LAI proved to be able to improve the intracanal distribution of 0.5% NaOCl after 60 s of activation, reaching the same level of effectiveness than 2.5% NaOCl. This is regarded as of clinical interest, since working with lower concentrations may contribute to reduce undesired effects.

Evaluation of the effectiveness of the photobiomodulation in the treatment of dentin hypersensitivity after basic therapy. A randomized clinical trial.

BACKGROUND: Dentin hypersensitivity (DH) in one of the most common causes of patient discomfort in the general population and its prevalence is higher in patients who have received basic or surgical periodontal treatment. Efficiency of the diode laser with different wavelengths has been studied by several authors, showing an improvement rate of the DH between 60-98%. The aim of the present study was to evaluate the effect of photobiomodulation (PBM) treatment on the reduction of DH after non surgical periodontal treatment. MATERIAL AND METHODS: A randomized split mouth clinical trial was performed involving 30 patients (120 teeth) diagnosed with DH after scaling and root planning. Two teeth of the experimental side were treated with the laser and 2 teeth of the control side were treated without activating the laser. The laser treatment parameters for each tooth were 660nm, 200mW, CW, illuminated area 1.15cm2, 173mW/cm2, 60 seconds, 12 J, 10.4J/cm2. Age, gender, smoking, plaque index, gingival recession, probing and VAS (for tactile and thermal stimulation) were registered before the laser treatment, immediate post treatment (after 2 minutes), 2 weeks, 1 month and 2 months after treatment. RESULTS: There was significant difference (p<0.01) in discomfort to thermal and mechanical stimulation between the control and diode laser treatment sites at all evaluation periods. The level of discomfort decreased immediately following diode laser therapy, and continued to demonstrate a decrease for the duration of the study. All teeth remained vital after laser treatment, without adverse reactions or complications. CONCLUSIONS: The PBM can be used to reduce DH without detrimental pulpal effects. Key words:Dental hypersensitivity, laser, diode laser, photobiomodulation.