Botulinum Toxin A in the Management of a Gummy Smile: A Clinical Controlled Preliminary Study.

BACKGROUND: Botulinum toxin type A (BTX-A) is recent technique for the treatment of gummy smile. OBJECTIVES: The aim of this randomized controlled preliminary clinical trial was to evaluate the effects of BTX-A on excessive gingiva display (EGD) reduction, muscle activity, and patient satisfaction at 2, 8, 12, 16, 21, and 25 weeks. METHODS: Group 1 (G1) received 4 points of BTX-A application (2 U/point) for relaxation of the levator labii superioris alaeque nasi and levator labii superioris muscles; Group 2 (G2) received 2 points of BTX-A (2 U/point) for relaxation of only the levator labii superioris alaeque nasi muscle. RESULTS: A high dropout of patients from follow-up sessions occurred. Therefore, because of this data limitation, the results were considered a preliminary outcome. At 2 weeks, there was a significant difference between baseline regarding the reduction of EGD in G1 and G2, reduction in muscle activity in G1, and increased satisfaction in G1 and G2. At 2 weeks, there was no difference between the 2 groups. Statistically significant EGD reduction was maintained until 16 weeks in G2 and 25 weeks in G1. After 14 days there was a gradual recovery of muscle activity in both groups until recovery of baseline values by 25 weeks. Patients' satisfaction with treatment lasted 21 weeks in G1 and 16 weeks in G2. CONCLUSIONS: Increasing the number of BTX-A injection points resulted in a prolonged effect regarding EGD reduction and patient satisfaction but did not increase the intensity of the outcome. However, due to the high dropout of patients, this is a preliminary conclusion and further studies are necessary to confirm these results.

Effect of gel replacement during in-office dental bleaching: a case report.

In-office dental bleaching allows the dentist to have greater control of the procedure and prevents patients from ingesting chemicals. To obtain optimum results, in-office bleaching usually requires a longer period of application as well as changes of the bleaching agent applied to the tooth surfaces at each appointment. The objective of this case report was to assess, by means of a split-mouth design in a single patient, the final tooth color and tooth sensitivity resulting from 2 different bleaching protocols: 1 application of 35% hydrogen peroxide for 45 minutes and 3 applications of 35% hydrogen peroxide for 15 minutes each. Neither the patient nor 5 individuals who were blinded to the techniques noted a difference in the final esthetic results of the 2 protocols immediately after the procedure. In addition, the patient reported that no tooth sensitivity was associated with either protocol. The results of dental bleaching on both sides were maintained after 15 days. The results shown in the present case report suggest that there may be no need to renew the gel during in-office dental bleaching.

A randomized placebo-blind study of the effect of low power laser on pain caused by irreversible pulpitis.

This randomized placebo-blind study aimed to evaluate the effect of laser phototherapy (LPT) on pain caused by symptomatic irreversible pulpitis (SIP). Sixty patients diagnosed with SIP were randomly assigned to treatment groups (n = 15): G1 (control), G2 (laser placebo-sham irradiation), G3 (laser irradiation at 780 nm, 40 mW, 4 J/cm2), and G4 (laser irradiation at 780 nm, 40 mW, 40 J/cm2). Spontaneous pain was recorded using a VAS score before (T0), immediately after (T1), and 15 min after treatment (T2). Local anesthetics failure during emergency endodontic treatment was also assessed. There was no pain difference in T1 and T2 between the experimental laser groups (G3 and G4) and the placebo group (G2). The 4-J/cm2 (G3) irradiation resulted in significant increase in the local anesthetics failure in lower jar teeth. This effect could be suggested as consequence of the LPT improvement in local circulation and vasodilatation that would result in the increase of local anesthetic agent absorption. The application of 780-nm diode laser irradiation, at 4 and 40 J/cm2, showed no effect in reducing the pain in SIP in comparison to the placebo group. The fluence of 4 J/cm2 showed a negative effect in local anesthetics, resulting in significant increase of complimentary local anesthesia during emergency endodontic treatment. This work provides evidence of the consequence of LPT application on teeth with symptomatic irreversible pulpitis. LPT should be avoided in teeth with pain due to irreversible pulpitis.

Protective effect of CO2 laser (10.6 µm) and fluoride on enamel erosion in vitro.

The aim of this study was to analyze the effect of CO(2) laser (10.6 µm) irradiation with 5-µs pulse width in prevention of enamel erosion due to citric acid exposure in vitro. One hundred forty-four bovine enamel samples were cut into 5 × 5 × 2-mm-size slabs and polished to obtain plane surfaces. Enamel surfaces were covered with acid-resistant varnish, except for a central area of 2.5 mm in diameter. The samples were divided into four groups (n = 12/group/day): C-control, no treatment; L-CO(2) laser irradiation (0.3 J/cm(2), 5 µs, 226 Hz); F-topical fluoride treatment, 1.25%F(-) (AmF/NaF) for 3 min; and FL-fluoride treatment + CO(2) laser. For erosive demineralization, samples were immersed in 40 ml of citric acid (0.05 M, pH 2.3) for 20 min two times per day during 5 days. After 1, 3, and 5 days, surface loss was measured by digital profilometer. According to the repeated measure ANOVA and post hoc comparisons, all the treatments showed statistically significant reduction of enamel loss as compared to control group, in all investigated times (p < 0.0001): L (52%,31%,37%); F (28%,24%,29%); FL (73%,55%,57%). Both CO(2) laser irradiation alone (L) and the combined laser-fluoride treatment (FL) caused less enamel loss than the fluoride group (F) in all days (p < 0.0001 for L in all times; and p < 0.0001, p = 0.0220 and p = 0.0051 for F, respectively, at days 1, 3, and 5). Under the conditions of this study, CO(2) laser irradiation (0.3 J/cm(2), 5 µs, 226 Hz) could effectively reduce enamel surface loss due to citric acid exposure, in vitro. This effect was still observed after 5 days of repeated acid exposures.

Photobiomodulation increases uprighting tooth movement and modulates IL-1ß expression during orthodontically bone remodeling.

This study investigated the effects of photobiomodulation (PBM) in acceleration of orthodontic movement of inferior molar uprighting movement. Thirty-four individuals, with indication of molar uprighting movement for oral rehabilitation, were randomly divided in two groups: verticalization + PBM (808 nm, 100 mW, 1 J per point, 10 points and 25 J/cm2 ) or verticalization + PBM simulation. Elastomeric chain ligatures were changed every 30 days for 3 months. FBM was performed immediately, 24 h, 72 h, 1 and 2 months after activation. The primary outcome was the amount of uprighting movement. Secondary outcomes were pain, amount of medication, OHIP-14 questionnaire, and cytokine IL-1ß. PBM group increase uprighting movement when compared to control after 3 months and modulate IL-1ß expression. For pain control, the amount of medication and OHIP-14 no difference were found. This study suggests that PBM accelerates tooth movement during molar uprighting, due to modulation of IL-1ß during bone remodeling.

Effectiveness of Violet LED alone or in association with bleaching gel during dental photobleaching: A Systematic Review.

AIMS: To conduct a systematic review to determine the efficacy of violet led in promoting dental bleaching by itself or accelerating dental bleaching when associated with peroxides. METHODS: Clinical and in vitro studies were identified by a search on November 27th 2020 in the PubMed and Scopus databases. Inclusion criteria were: 1) studies related to bleaching; 2) studies related to violet LED Light (405-410nm); and 3) studies that analyzed efficacy. The authors assessed the studies for risk of bias independently. Authors extracted outcomes including color change evaluation and pain assessment independently. RESULTS: During the search process, 895 articles were found in the previously cited databases. After the first screening consisting of title and abstract evaluations, 18 articles were selected. Finally, 13 articles met the eligibility criteria and were included in this review, being 5 clinical trial/case series and 8 in vitro studies. In vitro studies showed a high risk of bias and interventional studies showed a low risk of bias. CONCLUSION: The violet Led seems to have the potential to bleach teeth without peroxides, with a clinical perceptible color alteration. However, the effect is small in comparison to bleaching using peroxides. When Violet Led is used in association with peroxides, it seems to potentialize the bleaching result. However, due to the high heterogeneity between studies, a small number of clinical studies, and the high risk of bias of the in vitro included studies, the results are not definitive, and further well-designed studies are needed to reach safe evidence.

Blinded, parallel and randomized clinical evaluation of in-office dental bleaching with violet LED (405-410nm).

This clinical study evaluated the effect of bleaching performed with violet LED light (405-410 nm), either combined with hydrogen peroxide (HP) gel, or not, on color change, dental sensitivity, participants' satisfaction and impact on their quality of life. A hundred participants were divided into one of the groups (n = 25): G1 - 35% HP (4 sessions, 1x/week); G2 - violet LED (4 sessions, 1x/week); G3 - violet LED (4 sessions, 2x/week); G4 - hybrid technique (violet LED + 35% HP; 4 sessions, 1x/week). Color evaluation was performed with colorimetric tests (objective and subjective), before, 14 days and 3 months after completion. Additionally, satisfaction with treatment, impact on quality of life (OHIP-14) and dental sensitivity were recorded. The data were submitted to statistical analysis, considering a significance level of 5%, with the exception of the data from the questionnaire on satisfaction (descriptive analysis). Two-way ANOVA and Tukey tests showed that there was no difference between color variation resulting from techniques used in G1 and G4; those used in G2 and G3 did not differ and were less effective for bleaching than those of the other groups, in both subjective and objective evaluations. Regarding tooth sensitivity, subjects in G2 and G3 experienced no sensitivity, ​​while those in G4 showed lower sensitivity values than those in G1. With respect to quality of life, only subjects in G1 and G2 showed a significant positive impact. Among the evaluated techniques, the hybrid type seemed to be a good alternative, showing effective bleaching with less tooth sensitivity.

Influence of 35% hydrogen peroxide gel renewal on color change during in-office dental photobleaching with violet LED: A split-mouth randomized controlled clinical trial.

BACKGROUND: To clinically evaluate the effect of 35% hydrogen peroxide gel renewal in association with violet LED (405-410nm) through a split-mouth randomized controlled clinical trial. METHODS: The treatment consisted in 3 bleaching sessions of 15 min each, with an interval of 7 days between them, using 35% hydrogen peroxide combined to violet LED irradiation. Selected patients had two experimental segments for the split-mouth design: No change of the bleaching gel during each session (NBGR) and 3 changes of the bleaching gel every 5 min for each session (BGR). During the 3 bleaching sessions, the selected quadrant received the same treatment. Patients had their upper canines and central incisors teeth color measured with a subjective (color scale - VITA Classical) and an objective (spectrophotometer - VITA Easyshade) method and their teeth sensitivity measured using a Visual Analog Scale (VAS) before, immediately after each bleaching session, and 14 days and 2 months (60 days) after the end of the treatment. RESULTS: The protocol adopted in the present study reached satisfactory results regarding color change. No statistical difference between groups was observed immediately after the end of the treatment and in the follow-up analysis for both subjective and objective color evaluation. No difference in tooth sensitivity between segments was observed. CONCLUSION: There is no need for bleaching gel renewal when following the clinical protocol of 3 sessions of 15 min in a bleaching protocol of 35% hydrogen peroxide combined with violet LED.

In-office bleaching protocols using violet LED: A split mouth case report.

A new LED wavelength, violet LED (VL) with a wavelength between 405 - 410 nm was recently introduced to be used for in-office dental bleaching. In comparison to the blue LED system (440 to 485 nm), the shorter wavelength has more energy carried in its photons and also corresponds to the absorption peak of the stained particles, which lead to whitening utilizing a physical process. Considering the need to suggest and develop new protocols with this new technology, this article reports 2 different dental bleaching protocols developed in a split-mouth model using VL. A 25-year-old male patient was submitted to in-office dental bleaching. On the teeth from the left side, the bleaching gel (35% H2O2) was renewed 3 times (every 8 mins), and on the right side, the gel was maintained without renewal during the bleaching session. The irradiation with Violet LED Light (405 nm ± 10 nm) was performed with the following protocol: 1 min of irradiation with 30 s light off until 8 min of total time. A total of 3 cycles were performed (total time of 24 min). Two bleaching sessions were performed with an interval of 7 days between sessions. Based on the results of this split-mouth case report, there was no visible difference in the final color outcome and sensitivity between both bleaching protocols tested.

Oral hygiene associated with antimicrobial photodynamic therapy or lingual scraper in the reduction of halitosis after 90 days follow up: A randomized, controlled, single-blinded trial.

BACKGROUND: Although antimicrobial photodynamic therapy (aPDT) can reduce halitosis immediately after application, it returns after a week. This probably occurs because bacteria residing in the oral cavity may recolonize the dorsum of the tongue. OBJECTIVE: Verify if modification of oral hygiene behavior associated with aPDT or lingual scraper can reduce halitosis after a 90-day follow-up. METHODS: Forty adults with positive halitosis were randomized in G1 (n = 20) -aPDT + oral hygiene behavior (OHB) or G2 (n = 20)- lingual scraper + OHB. G1 group were submitted to 0.005 % methylene blue in the middle and posterior third of the tongue, with pre-irradiation of 1 min. Irradiations were performed with red laser diode (λ =660 nm), 100 mW, 318 J/cm2, 3537 mW/cm2, 9 J per point at 6 points. In the G2 group, the tongue was scraped 10 times on the right side and on the left side with a tongue scraper. All patients were instructed on OHB at baseline, 7 and 90 days (guidance on the use of dental floss and the Bass technique for brushing). Halitosis was evaluated by gas chromatography (OralChroma®). Values ​​> 112 ppb for Hydrogen sulfide (H2S) gas was considered positive halitosis. Methylmercaptanes and dimethylsulfide were also measured. The gas measures were assessed at baseline, immediately, and at 7 and 90 days. Paired t-test was used for the statistical analysis. For comparison between groups, the t-test was used. Values of p < 0.05 were considered statistically significant. RESULTS: There was no difference between groups immediately after treatment (p = .1532) after 7 days (p = 0.9312) and 90 days (p = 0.6642). For the aPDT group, there was a decrease in hydrogen sulfide ​​immediately after treatment (p = 0.0001), after 7 days, values remained 3-fold smaller (p = 0.0088) and 2-fold smaller after 90 days (p = 0.0270). For the scraper group, there was a decrease immediately after treatment (p = 0.0001), the values remains 2-fold smaller ​​(p = 0.0003) after 7 days and 3 months (p = 0.0001). CONCLUSION: The oral hygiene behavior associated with aPDT or tongue scraper was not able to reduce halitosis after 90-day follow-up. Despite halitosis remaining ​​ higher than 112 ppb in all follow-up periods, the mean values remain 2 or 3 fold smaller than baseline values. Future studies should include other oral hygiene behavior to achieve better results in the treatment of halitosis.

Comparison of dentin root canal permeability and morphology after irradiation with Nd:YAG, Er:YAG, and diode lasers.

The aim of this study was to compare the effects of Nd:YAG, Er:YAG, and diode lasers on the morphology and permeability of root canal walls. The three laser wavelengths mentioned interact differently with dentin and therefore it is possible that the permeability changes caused will determine different indications during endodontic treatment. Twenty-eight human single-rooted teeth were instrumented up to ISO 40 and divided into four groups: group C, control (GC), non-laser irradiated; group N (GN), irradiated with Nd:YAG laser; group E (GE), with Er:YAG laser and group D (GD) with diode laser. After that, the roots were filled with a 2% methylene blue dye, divided into two halves and then photographed. The images were analyzed using Image J software and the percentage of dye penetration in the cervical, middle, and apical root thirds were calculated. Additional scanning electron microscopy (SEM) analyses were also performed. The analysis of variance (ANOVA) showed significant permeability differences between all groups in the middle and cervical thirds (p < 0.05). The Tukey test showed that in the cervical third, GN presented means of dye penetration statistically significantly lower than all of the other groups. In the middle third, GE and GD showed statistically higher dye penetration means than GC and GN. SEM analysis showed melted surfaces for GN, clean wall surfaces with open dentinal tubules for GE, and mostly obliterated dentinal tubules for GD. Er:YAG (2,094 nm) laser and diode laser (808 nm) root canal irradiation increase dentinal permeability and Nd:YAG (1,064 nm) laser decreases dentin permeability, within the studied parameters.

Laser phototherapy in the treatment of periodontal disease. A review.

Many studies in the literature address the effect of low-power lasers in the management of pathologies related to periodontal tissues. Due to the lack of standardized information and the absence of a consensus, this review presents the current status of laser phototherapy (LPT) in periodontics and discusses its benefits and limits in the treatment of periodontal disease. The literature was searched for reviews and original research articles relating to LPT and periodontal disease. The articles were selected using either electronic search engines or manual tracing of the references cited in key papers. The literature search retrieved references on wound and bone healing, analgesia, hypersensitivity, inflammatory process and antimicrobial photodynamic therapy. Each topic is individually addressed in this review. The current literature suggests that LPT is effective in modulating different periodontal disease aspects in vitro, in animals, and in simple clinical models. Further development of this therapy is now dependent on new clinical trials with more complex study designs.

A minimally invasive procedure for esthetic achievement: enamel microabrasion of fluorosis stains.

Esthetic alterations (such as fluorosis) that result from intrinsic dental staining in enamel and dentin can be controlled or softened by noninvasive methods such as dental bleaching or enamel microabrasion. Part of the enamel is removed during microabrasion; however, this wear is clinically insignificant and does not harm the dental structure. This article presents a case in which the microabrasion technique was used to remove fluorosis staining. Based on the results of this case report, it can be concluded that this technique is efficient and can be considered a minimally invasive procedure.

Photobiomodulation and Mandibular Advancement Modulates Cartilage Thickness and Matrix Deposition in the Mandibular Condyle.

Objective: We evaluated the effects of photobiomodulation (PBM), mandibular advancement (MA), and the combination of both treatments (PBM+MA) on condylar growth, by the analysis of cartilage and bone formation, fibrillar collagen deposition, proteoglycan content, cell proliferation, and clastic cell index (CCI). Methods: Forty male Wistar rats were randomly assigned to CONTROL, PBM, positive control-MA, and PBM+MA groups. The appliance was worn 10 h/day. Laser was irradiated bilaterally on mandibular condyles in 8 alternate days (1 irradiation point per condyle) using the following parameters: 780 nm, 10 J/cm2, 40 mW, 1 W/cm2, 10 sec/point, 0.4 J/point, and cumulative dose per point: 3.2 J. PBM+MA received both treatments simultaneously. After 15 days, the animals were euthanized and the condyles dissected and embedded in paraffin. Histological sections from the intermediate portion of the condyle were used for morphometric analysis. The relative frequency (%) of fibrillar collagens was determined in sections stained with picrosirius red-hematoxylin under polarized light or Gömöri's method for reticular fibers. Proteoglycan content was evaluated by computerized photocolorimetric analysis. CCI was determined by tartrate-resistant acid phosphatase (TRAP), and proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. Results: PBM and MA influenced condylar cartilage thickeness and matrix deposition, but none of the treatments affected significantly the area of the condyle. CCI were not influenced by the treatments, but clastic cells distribution was influenced by MA and PBM+MA treatments. There was no significant difference in proliferating cells among the groups. Conclusions: This study demonstrated that PBM and MA stimulates matrix deposition and cartilage thickening in the mandibular condyle, but was not able to demonstrate a synergistic effect between the treatments. Additional studies should be conducted to evaluate the possible synergistic effect between PBM and MA.

Immediate laser-induced hemostasis in anticoagulated rats subjected to oral soft tissue surgery: a double-blind study.

Given the growing trend towards medical indications for continuous use of anticoagulants, the number of patients on these medications continues to rise. The management of patients on oral anticoagulants requiring oral surgical procedures has aroused much controversy. Changes in an anticoagulation regimen are associated with an increased risk of thromboembolism. However, it seems logical and advantageous for the patients' health if surgery could be performed without any change to the anticoagulation therapy. In dentistry, high-power lasers have been poorly explored in this field. The hemostatic properties of high-power lasers could be helpful during oral soft tissue surgeries in anticoagulated patients. The aim of this study was to compare bleeding time in anticoagulated rats after lingual frenectomy performed with a scalpel or diode laser with bleeding time in healthy animals. Twenty-four male Wistar rats were assigned to four groups (n = 6): (CS) Control-Scalpel Surgery; (AS) Anticoagulated-Scalpel Surgery; (CL) Control-Laser (diode laser 810 nm/1.5 W) Surgery; and (AL) Anticoagulated-Laser Surgery (diode laser 810 nm/1.5 W). Warfarin administration was used to induce anticoagulation. Blood was blotted every 30 seconds with filter paper until bleeding stopped to verify bleeding time. Two blinded researchers performed the surgeries and collected the bleeding time data. Diode laser surgery led to complete hemostasis in rats during and after lingual frenectomy. Zero bleeding was assessed during surgeries and after diode laser surgeries in anticoagulated rats. Laser-induced hemostasis offered an alternative solution to the controversial issue of intraoperative and postoperative bleeding control in patients on anticoagulation therapy.

Analysis of the interfacial micromorphology of adhesive systems in cavities prepared with Er,Cr:YSGG, Er:YAG laser and bur.

The purpose of this in vitro study was to evaluate the interaction pattern of adhesive systems on laser and bur cavities. Cavities were prepared according to the following groups (n=9): (G1) conventional diamond bur (No. 1013); (G2) Er:YAG laser (250 mJ, 4 Hz, 80.6 J/cm2); (G3) Er,Cr:YSGG laser (3.5 W, 20 Hz, 61.7 J/cm2). After cavity preparation, specimens were divided into three subgroups differing the adhesive systems used (n=3): (GA) AdheSE; (GB) Clearfil standard error (SE) Bond; (GC) Single Bond. After insertion of a micro-hybrid composite resin, the specimens were sectioned across the bonded surface dividing the teeth into two halves, which were prepared for SEM analysis. Cavities prepared with laser appeared to be more irregular than the bur cavities. Different patterns of gap formation and resin tags could be observed, showing the differences, advantages, and disadvantages of both types of cavities. Under the settings of the present study, resin tags were more pronounced in lased dentin than bur prepared dentin independently of the bonding systems used. On the other hand gap formation between dentin and resin in laser prepared cavities was observed suggesting collagen alteration.

Photobiomodulation in the Prevention of Tooth Sensitivity Caused by In-Office Dental Bleaching. A Randomized Placebo Preliminary Study.

OBJECTIVE: Analyze the effect of photobiomodulation in the prevention of tooth sensitivity after in-office dental bleaching. BACKGROUND DATA: Tooth sensitivity is a common clinical consequence of dental bleaching. Therapies for prevention of sensitivity have been investigated in literature. MATERIALS AND METHODS: This study was developed as a randomized, placebo blind clinical trial. Fifty patients were selected (n = 10) and randomly divided into five groups: (1) control, (2) placebo, (3) laser before bleaching, (4) laser after bleaching, and (5) laser before and after bleaching. Irradiation was performed perpendicularly, in contact, on each tooth during 10 sec per point in two points. The first point was positioned in the middle of the tooth crown and the second in the periapical region. Photobiomodulation was applied using the following parameters: 780 nm, 40 mW, 10 J/cm2, 0.4 J per point. Pain was analyzed before, immediately after, and seven subsequent days after bleaching. Patients were instructed to report pain using the scale: 0 = no tooth sensitivity, 1 = gentle sensitivity, 2 = moderate sensitivity, 3 = severe sensitivity. RESULTS: There were no statistical differences between groups at any time (p > 0.05). More studies, with others parameters and different methods of tooth sensitivity analysis, should be performed to complement the results found. CONCLUSIONS: Within the limitation of the present study, the laser parameters of photobiomodulation tested in the present study were not efficient in preventing tooth sensitivity after in-office bleaching.

In vitro evaluation of methylene blue removal from root canal after Photodynamic Therapy.

In Endodontics, photosensitizers' such as methylene blue and toluidine blue have been used in Photodynamic Therapy due to their positive results. However, they can stain the dentin from the root canal after Photodynamic Therapy (PDT). The present in vitro study aimed to evaluate different stain removal protocols from root canal after PDT using methylene blue (MB) dye. After mechanical preparation of the root canal of 40 uni-radicular human teeth, PDT was performed using 0,01% MB with parameters of 3min of pre-irradiation and a diode laser irradiation emitting at 660nm, 40mW, 4min, 9.6J. After PDT, different protocols of MB removal were performed: Group 1 - control (0.9% saline solution); Group 2 - sodium hypochlorite (2.5% NaOCl); Group 3-17% ethylenediamine tetraacetic acid (EDTA); Group 4 - passive ultrasonic irrigation (PUI); The color of the dentin of the root canal was measured, before, immediately after the PDT and immediately after the cleaning using a spectrophotometer. The ΔE values found were statistically compared using the ANOVA and Tukey's tests (α=0.05). All the treatments lead to some cleaning of root canal after PDT, however, none of the treatments tested completely removed all staining caused by MB photosensitizer of the root canal. Among the treatments tested, PUI and Hypochlorite 2.5% promoted greater cleaning, with no statistically significant difference between them. In conclusion, within the protocols tested in the present study, no treatments were able to completely remove MB staining of the root canal after PDT.

Effect of Nd:YAG and CO2 Laser Irradiation on Prevention of Enamel Demineralization in Orthodontics: In Vitro Study.

OBJECTIVE: The aim of this study was to investigate Nd:YAG and CO2 laser effects in the prevention of demineralization in deeper layers of enamel via successive acid challenge cycles. BACKGROUND DATA: Lasers are promising in the prevention of enamel demineralization around the orthodontic brackets; however, there are very few studies that evaluate if the effects of treatment could be extended after successive acid challenge cycles due to permanent enamel structural alterations. MATERIALS AND METHODS: Human enamel samples were divided into five groups (n = 12): G1-application of 1.23% acidulated fluoride phosphate gel (AFP, control); G2-Nd:YAG laser irradiation (0.6 W, 84.9 J/cm2, 10 Hz, 110 µs, contact mode); G3-Nd:YAG laser irradiation associated with AFP; G4-CO2 laser irradiation (0.5 W, 28.6 J/cm2, 50 Hz, 5 µs, and 10 mm focal distance); and G5-CO2 laser irradiation associated with AFP. The samples were submitted to successive acid challenge cycles. Quantitative light-induced fluorescence and scanning electron microscopy were used to assess enamel demineralization. The data were statistically compared (α = 5%). RESULTS: G1: 50.87 ± 4.57; G2: 47.72 ± 2.87; G3: 50.96 ± 4.01; G4: 28.21 ± 2.19; and G5: 30.13 ± 6.38. The CO2 laser groups had significantly lower mineral losses than those observed in all other groups after successive acid challenge cycles. CONCLUSIONS: Only the CO2 laser (10.6 µm) irradiation prevents enamel demineralization around the orthodontic brackets even after exposure to successive acid challenges. The CO2 laser at 10.6 µm showed a deeper effect in enamel regarding caries prevention.

Randomized in vivo evaluation of photodynamic antimicrobial chemotherapy on deciduous carious dentin.

The aim of this randomized in vivo study was to compare antimicrobial chemotherapies in primary carious dentin. Thirty-two participants ages 5 to 7 years underwent partial caries removal from deep carious dentin lesions in primary molars and were subsequently divided into three groups: control [chlorhexidine and resin-modified glass ionomer cement (RMGIC)], LEDTB [photodynamic antimicrobial chemotherapy (PACT) with light-emitting diode associated with toluidine blue solution and RMGIC], and LMB [PACT with laser associated with methylene blue solution and RMGIC]. The participants were submitted to initial clinical and radiographic examinations. Demographic features and biofilm, gingival, and DMFT/DMFS indexes were evaluated, in addition to clinical and radiographic followups at 6 and 12 months after treatments. Carious dentin was collected before and after each treatment, and the number of Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Fusobacterium nucleatum, Atopobium rimae, and total bacteria was established by quantitative polymerase chain reaction. No signs of pain or restoration failure were observed. All therapies were effective in reducing the number of microorganisms, except for S. sobrinus. No statistical differences were observed among the protocols used. All therapies may be considered as effective modern approaches to minimal intervention for the management of deep primary caries treatment.