Patricia Moreira de Freitas

Background: This study evaluated the effect of Erbium:Yttrium–Aluminum–Garnet (Er:YAG) laser irradiation on the fracture load, failure mode, and reliability of monolithic and porcelain-veneered zirconia crowns. Methods: Monolithic ultra-translucent zirconia crowns (5YZ-M, n = 30) and porcelain-veneered zirconia crowns (3YZ-V, n = 30) were divided into control (Ctrl-no surface treatment) and Er:YAG laser irradiation (Las) groups (n = 15). Las was performed on the cementation surface (250 mJ, 10 Hz, 2.5 W for 30 s). Crowns were adhesively cemented onto dentin-analog abutments and subjected to compressive load-to-failure testing. Data were analyzed by two-way ANOVA, Tukey’s post hoc test, and Weibull analysis (α = 0.05). Fractographic analysis was performed. Results: Laser irradiation did not affect the fracture load (p = 0.183). Monolithic crowns (5YZ-M) showed significantly higher fracture load than veneered crowns (3YZ-V) (p < 0.001). There was no effect of the interaction between factors (p = 0.150). The m-values were similar among groups, while the L₀ of 3YZ-V-Ctrl was significantly lower than that of 5YZ-M. Veneered restorations predominantly showed chipping and delamination; whereas, monolithic crowns mainly exhibited catastrophic failures. Fracture origins were mostly located at the occlusal loading area. Conclusions: Er:YAG laser irradiation of the cementation surface did not affect the load-bearing capacity or structural reliability of zirconia crowns.

Background: Among the traumatic dental injuries (TDIs), lateral luxation may present poor prognosis due to frequent root resorption and consequent tooth loss. Photobiomodulation therapy (PBMT) modulates cellular activities (proliferation, differentiation, growth factor secretion) and may improve outcomes. Objective: This randomized, double‐blind, placebo‐controlled trial evaluated PBMT (660 vs. 808 nm) for post‐operative pain and pulp sensitivity recovery in lateral luxation of permanent anterior teeth. Methods: Initially, 41 patients were included, with a total of 63 teeth traumatized by lateral luxation and were allocated to G1 ( n = 21): Splinting + sham PBM (placebo), G2 ( n = 21): Splinting + 808 nm infrared PBM and G3 ( n = 21): Splinting + 660 nm red PBM. Four weekly sessions (3 J/point, 3 points) were administered. Pain (by numeric rating scale) and pulp sensitivity (by cold test) were assessed weekly. Pain was analyzed using the Kruskal‐Wallis test, followed by multiple comparisons using Dunn's method with Bonferroni correction, and pulp sensitivity by a logistic regression model ( p < 0.05). Results: Three participants (total of 5 teeth) were excluded due to loss to follow‐up. Fifty‐eight teeth were analyzed (G1 = 21, G2 = 17, G3 = 20). Pain: All groups showed a significant reduction in pain over time ( p < 0.001). Both G2 and G3 demonstrated a significantly greater reduction in pain compared to G1 ( p < 0.001 and p = 0.026, respectively). No significant difference in pain reduction was observed between G2 and G3. Pulp sensitivity: G2 showed a significant improvement over time ( p < 0.001), despite starting from a more unfavorable baseline. In contrast, no significant change in pulp sensitivity was observed for G1 or G3 between the initial and final assessments. Conclusion: Within the limitations of this clinical study, all intervention groups were effective in reducing pain in lateral luxation of permanent anterior teeth, with superior results for laser groups compared to the placebo. However, only the 808 nm laser irradiation protocol demonstrated a significant improvement in pulp sensitivity, suggesting it may offer a more complete therapeutic response.

Dentin hypersensitivity (DH) is characterized by intense, short-lasting pain, triggered by dentin exposure to different stimuli. It is often associated with hypomineralized teeth due to increased enamel porosity and exposed dentinal tubules. The high-power Er: YAG laser has emerged as a promising therapeutic strategy for the treatment of this condition. The aim of this in vitro study was to test different protocols for managing dentin hypersensitivity in hypomineralized teeth using a high-power Er: YAG laser. Six protocols were evaluated, varying in power, frequency, application mode, and the use of cooling. Qualitative analysis of morphological changes were evaluated by scanning electron microscopy (SEM). Further, the most promising protocol – 20 mJ, 10 Hz, 0.20 watts, applied in focused mode, without cooling – was selected for assessing intrapulpal temperature variation using thermocouples connected to a monitoring system. The SEM images showed that this protocol promoted homogeneous surface melting of dentin, effectively sealing the dentinal tubules without inducing a thermal increase greater than 2 °C. These findings support the feasibility of using the Er: YAG laser with conservative parameters and no cooling as a safe and effective alternative for the management of DH in hypomineralized teeth. However, clinical trials are recommended to validate its applicability in pediatric dentistry.

To evaluate the effect of Nd:YAG laser irradiation on intraradicular dentin prior to obturation with calcium silicate-based and epoxy resin-based sealers, focusing on push-out bond strength, failure pattern using a stereomicroscope, adhesive interface quality via confocal laser scanning microscopy (CLSM), chemical composition using Raman spectroscopy, and dentin surface morphological alterations through scanning electron microscopy (SEM). Forty-six teeth were sectioned to standardize root length (16 mm) and prepared using a reciprocating R50 instrument. Specimens were randomly divided into control (no treatment) and Nd: YAG laser (1,064 nm) groups, with laser irradiation performed at 1.5 W, 25 Hz, for 20 s using a 400 μm fiber in a helical motion (1.5 mm/s). Twenty specimens per group were obturated using the single-cone technique with R50 gutta-percha and further subdivided by sealer: AH Plus (n = 10) and Bio-C Sealer (n = 10), with and without laser treatment. Three non-obturated specimens per group underwent Raman spectroscopy and SEM analysis of intracanal dentin. After 30 days at 37 °C, obturated samples were sectioned into slices (nine per specimen). The first two slices per third underwent push-out bond strength testing and failure analysis, while the third was examined via CLSM for adhesive interface quality. Bond strength was analyzed using three-way ANOVA, chemical composition by two-way ANOVA, failure patterns by chi-square, and interface adaptation by Kruskal-Wallis with post-hoc tests (p < 0.05). In laser groups, Bio-C Sealer showed higher bond strength in the cervical third (p = 0.011), whereas AH Plus maintained superior values in the middle and apical thirds (p < 0.001). The laser group obturated with Bio-C Sealer demonstrated adhesive interface adaptation comparable to the control group obturated with AH Plus (p = 1.000) and superior to the control group obturated with Bio-C Sealer (p = 0.037). Laser groups exhibited more mixed failures, while control groups showed a higher prevalence of adhesive failures (p = 0.045). Laser irradiation resulted in lower organic content intensity in the cervical third (p = 0.002) and an increased inorganic/organic ratio (p < 0.001). Additionally, it induced fusion and obliteration of dentinal tubules in the cervical third, whereas alternating areas of fused dentin and exposed tubules were observed in the middle and apical thirds. The Nd:YAG laser treatment of intraradicular dentin prior obturation positively influenced the obturation process when associated with Bio-C Sealer, particularly in the cervical third. Therefore, Nd:YAG laser may be a promising approach to enhance bond strength and improve the adhesive interface quality of obturations performed with calcium silicate-based sealers.

Background/Purpose: The therapeutic use of low‐level lasers aims to promote tissue photobiomodulation without raising the local temperature. However, in darker‐skin patients, melanin can increase temperature and cause adverse effects such as photosensitivity, especially in protocols with higher irradiances, such as those used in dual irradiations. Therefore, through a retrospective cohort, this project assesses the relationship between self‐reported skin color and the frequency of photosensitivity in patients treated with simultaneous dual irradiation protocols at the School of Dentistry of the University of São Paulo. Methods: Data from patients treated with lasers between 2013 and 2023 were retrieved. Patients were divided into two groups based on skin color and assessed for photosensitivity after simultaneous irradiation with red and infrared wavelengths. Statistical analyses investigated the relationship between photosensitivity, skin color, patient characteristics, and delivered energy. Results: Self‐reported skin color was associated with photosensitivity, with dark‐skinned patients having a three times higher risk of heating or thermal injury. The risk of clinically visible thermal injuries was nearly 12 times higher for this group compared to those with lighter skin. There was no correlation between the energy used and the degree of photosensitivity, nor was there a significant difference in energy between patients with and without photosensitivity. Conclusion: Self‐reported skin color was associated with photosensitivity occurrence during simultaneous laser wavelengths irradiation. Further studies are needed to investigate the mechanisms underlying the relation between melanin and irradiance. Finally, individualized photobiomodulation protocols are needed to ensure patient safety and optimize the therapy's expected effects.

The aim of the present study is to report a clinical case of a patient diagnosed with a late adverse reaction to the injection of filler material - persistent and intermittent delayed swelling (PIDS) - in which photobiomodulation therapy (PBMT) with low-power laser was used for edema reduction. This is an observational, descriptive, and retrospective work of a case report. The female patient, aged 73 years old, had undergone dermal filler six years before and complained of increased volume in the face region (glabellar region, labiomental sulcus, and nasolabial folds) and was submitted to ultrasound and anatomopathological analysis. PBMT using a low-power laser (660 nm and 808 nm, simultaneous irradiation, in contact, 2 J/point, 100 mW) proved to be effective for the non-invasive approach of late adverse reaction to dermal filler, such as PIDS, a common complication related to the use of dermal fillers.

The main symptoms of temporomandibular disorders (TMDs) are pain from musculoskeletal and/or joint—in the head and neck region—and complaints of difficulty in mandibular movements. The photobiomodulation therapy (PBMT) has been reported as a promising treatment in the management of these symptoms. The objective of this research was to assess the effect of PBMT immediately after irradiation on TMDs symptoms under a prospective clinical trial, randomized, triple-blinded, placebo-controlled, and with two parallel arms. According to the RDC/TMD, maximum mouth opening (MMO) and pain in the orofacial/cervical muscles and temporomandibular joint (TMJ) were recorded. One hundred forty-five participants (71 placebo and 74 PBMT experimental) were analyzed after irradiation protocols (sham-PBMT or PBMT) at the orofacial/cervical skull musculature and at the TMJ. The results showed a reduction in the total pain score (p = 0.026), a reduction in the number of painful points (p = 0.013), and an increase in the MMO (p = 0.016) in the PBMT protocol group when compared to the placebo protocol (sham-PBMT). The PBMT was shown to be effective in reducing orofacial/cervical skull pain immediately after the irradiation. It is clinically relevant and should be taken into consideration by professionals who are dedicated to treating this pathology because, in addition to bringing comfort to patients who need dental treatment, it also consists of a low-cost and low technical complexity clinical approach.

The present manuscript is a clinical case report in which antimicrobial photodynamic therapy (aPDT) - using a low-power laser (660 nm) associated with methylene blue photosensitizer (0.01%) - was considered for treating a case of complication after implantation of spiculated polydioxanone (PDO) threads, an aesthetic procedure worldwide performed in facial cosmetic non-surgical procedures. A 72-year-old female patient presented an infection in the face region where the PDO thread was implanted (mandible angle). After divulsion and local drainage, it was decided to associate aPDT using a low-level laser associated with a 0.01% methylene blue photosensitizer. Two sessions of aPDT were performed - on sequential days - and within 48 hours the region was dry and without signs of secretion. The use of aPDT seems to be a promising and effective option in cases of infections after implantation of PDO threads, consisting of a safe technique, of low execution complexity and without adverse effects.

Orthodontics is constantly seeking innovation towards mechanical efficiency and better oral-related quality of life during treatment. This narrative review aims to discuss novel scientific reports about light therapies and how they can optimize different stages of orthodontic intervention: before, during, and after treatment. Recurrent conditions that can be treated with laser devices are the removal of carious tissue, dentin hypersensitivity, and temporomandibular disorders. Evidence reveals that laser procedures accelerate health recovery, enabling individuals to initiate orthodontic treatment. Along orthodontic procedure, photobiomodulation therapy, is indicated for analgesia after appliance activations, repair of traumatic ulcers, and acceleration of tooth movement. Moreover, antimicrobial photodynamic therapy is well-indicated for effective decontamination of oral infections such as herpetic lesions and peri-implantitis. Finally, high-intensity lasers are good allies in removing brackets and reconditioning red esthetics. There are many benefits to the use of light sources in the orthodontic routine: simplicity of technique, ease of handling devices, minimal invasiveness, and patient comfort during procedures. It is essential that professionals develop a critical overview of technological advances, offering safe and evidence-based therapies. Recent advances indicate that laser therapies improve patient experiences during orthodontic treatment and minimize the side effects of clinical interventions.