The influence of two photobiomodulation protocols on orthodontically induced inflammatory root resorption (a randomized controlled clinical trial).

BACKGROUND: Controversial results have been reported regarding the impact of photobiomodulation (PBM) on orthodontically induced inflammatory root resorption (OIIRR). The aim of this study was to evaluate the influence of two PBM protocols, one of them requiring a high application frequency (on days 0, 3, 7, 14, then every 2 weeks), while the second requires less frequent applications (every 3 weeks), on OIIRR accompanying orthodontic treatment. METHODS: Twenty female patients were recruited for this randomized controlled trial, requiring the therapeutic extraction of maxillary first premolars, and they were randomly divided into 2 equal groups. In Group A, one side of the maxillary arch randomly received PBM on days 0, 3, 7, 14, and every 2 weeks thereafter, while in Group B, one side was randomly chosen to receive PBM every 3 weeks. The laser applied was a Diode laser with a wavelength of 980 nm, in a continuous mode. Canine retraction in both groups was carried out using closed-coil springs, delivering 150 g of force, and the force level was checked every 3 weeks, over a 12-week study period. Pre-retraction and post-retraction cone-beam computed tomography (CBCT) was done for the evaluation of OIIRR. RESULTS: No significant differences in the amount of OIIRR have been reported between the laser and control sides in both groups A and B. Also, no significant differences have been reported between the laser sides in both groups. CONCLUSIONS: Photobiomodulation does not affect OIIRR, whether by increasing or decreasing its occurrence, with both laser application protocols. Therefore, it can be stated that PBM does not result in root resorption less than the commonly observed range elicited with conventional orthodontic treatment, and that it has no effect on OIIRR. Trial registration Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction (NCT04926389), 15/06/2021-retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04926389 .

Láser de baja potencia como coadyuvante en tratamiento endodóntico de pieza con reabsorción interna y lesión apical: reporte de un caso / Use of low level laser as an adjunct in endodontic treatment of teeth with internal resorption and apical lesión

La reabsorción radicular interna es infrecuente en dentición permanente, la mayoría de los casos se observan en dientes anteriores, su etiología no está del todo clara, es por esto que el tratamiento para este tipo de lesiones es la endodoncia. Se presenta el caso de una paciente sexo femenino, 38 años de edad, sin antecedes médicos relevantes, derivada para evaluación de diente 2.2 con mal pronóstico. El diagnóstico es de absceso apical agudo, pieza con reabsorción interna y lesión apical. Se realiza endodoncia con cementos biocerámicos y aplicación de láser terapéutico de 808 nm de longitud de onda, con parámetros específicos para acelerar la reparación del tejido óseo. La terapia de fotobiomodulación con láser de baja potencia parece ser útil como coadyuvante en el proceso de reparación ósea en piezas con lesión apical y reabsorción interna tratadas endodónticamente.

Internal root resorption is infrequent in permanent dentition, most cases are observed in anterior teeth, its etiology is not entirely clear, which is why the treatment for this type of lesion is endodontics.We present the case of a 38-year-old female patient, without relevant medical history, referred for evaluation of tooth 2.2 with a poor prognosis. Diagnosis Acute apical abscess, tooth with internal resorption and apical lesion. Endodontics are performed with bioceramic cements and the application of a 808 nm wavelength therapeutic laser, with specific parameters to accelerate bone tissue repair.Low-level laser photobiomodulation therapy appears to be useful as an adjunct in the bone repair process in endodontically treated teeth with apical lesion and internal resorption.

Effects of photobiomodulation at different wavelengths on orthodontically induced root resorption in orthodontic retention period: a micro-CT and RT-PCR study.

The aim of this study was to evaluate and compare the reparative and inhibitory effects of single wavelength photobiomodulation (SW-PBM) and of cumulative increased wavelength photobiomodulation (CW-PBM) on orthodontically induced inflammatory root resorption (OIIRR). Thirty-three Wistar albino rats were divided into five groups: untreated group (negative control), only relapse group (positive control-1), only retention group (positive control-2), SW-PBM group (650 nm, 100 mW/cm2), and CW-PBM group (532-650-940 nm, 100 mW/cm2). Orthodontic tooth movement was induced experimentally in rats for 10 days with an applied force of 50 cN; retention and therapeutic approaches were performed concurrently. At the end of the experiment, maxillary quadrants were prepared for micro-CT analysis and real-time polymerase chain reaction (RT-PCR) analysis. After the Shapiro-Wilk normality test, Kruskal-Wallis test followed post hoc Bonferroni test and paired samples t test was used for statistical evaluation of the data. Resorption lacunae volume (p < 0.001), number of resorption lacunae (p < 0.05), and percentage of the resorption (PR) lacunae (p < 0.001) decreased with PBM applications when compared with the positive control groups, and the mean PR was similar in the negative control group when compared with SW-PBM group. Receptor activator of nuclear factor kappa B ligand (RANKL) levels of the PBM groups were lower (p < 0.05) than those of the positive control groups. Cyclooxygenase-2 (COX-2) expression levels significantly decreased with PBM administration (p < 0.05). No significant change was found in osteoprotegerin (OPG) expression levels and OPG/RANKL ratios (p > 0.05). PBM applications showed marked inhibitory and reparative effects on OIIRR by modulating the RANKL and COX-2 expression levels. However, the effects of the different wavelengths were similar to each other.Graphical abstract.

Effects of low-level laser on the repair of orthodontically induced inflammatory root resorption: a systematic review of studies in rats / Efectos del láser de bajo nivel en la reparación de la reabsorción radicular inflamatoria inducida por ortodoncia: una revisión sistemática de estudios en ratas

Orthodontically induced inflammatory root resorption (OIIRR) is a complication of dental treatment which consists of the degradation of local tissue due to an inflammatory reaction provoked by inappropriate orthodontic stimulus. The aim of the present systematic review was to assess the effectiveness of low-level laser therapy (LLLT) in reducing orthodontically induced inflammatory root resorption (OIIRR) in animal models. A systematic review was carried out in the MEDLINE, EMBASE and LILACS databases. Studies of interventions in animals were selected which analysed the effect of LLLT on OIIRR repair. The risk of bias was analysed through the 10 domains of the SYRCLE RoB tool for animal studies. Seventy-one studies were found; 27 were eliminated as duplicates and 44 titles/abstracts were analysed. Of these, 38 were excluded, and five studies were included for qualitative analysis. In 66.6 % of the studies included, the authors state that LLLT was effective in the inhibition/repair of OIIRR. In histological analysis it was observed that root resorption was significantly less in animals treated with laser as compared to the control. Furthermore, LLLT accelerated cicatrization after OIIRR. Laser proved effective in reducing root resorption lacunae and shortening the inflammatory process induced by the application of orthodontic force.

La resorción radicular inflamatoria inducida por tratamiento ortodontico (RRIITO) es una complicación del tratamiento odontológico que consiste en la degradación del tejido local debido a una reacción inflamación provocada por un estímulo ortodóntico inadecuado. El objetivo fue analizar la efectividad de la terapia láser de baja intensidad (LBI) en la disminución de RRIITO en ratas. Se realizó una revisión sistemática en las bases MEDLINE, EMBASE y LILACS. Fueron utilizados los términos 'resorción radicular', 'láser de baja intensidad', 'fototerapia', 'tratamiento ortodóntico', 'movimiento dental'. Fueron seleccionados estudios de intervención en animales, que analizaron el efecto del LBI en la reparación de la RRIITO. Los riesgos de sesgos fueron analizados mediante los 10 domínios de la herramienta SYRCLE RoB para estudios en animales. 71 estudios fueron encontrados, siendo eliminados 27 duplicados, y analizados 44 títulos/abstracts; de estos, fueron incluídos 5 estudios para análisis cualitativa. El 66,6 % de los estudios incluidos afirman que el LBI fue efectivo em reparar la RRIITO. En el análisis histológico se observó que la RRIITO fue significativamente menor en animales tratados con láser en comparación con el control. Además de eso, el LBI aceleró el proceso de cicatrización de la RRIITO. El láser se mostró efectivo en reducir las lagunas de resorción radicular y acortar el proceso inflamatorio inducido por la aplicación de fuerzas ortodonticas.

Physical properties of root cementum: Part 27. Effect of low-level laser therapy on the repair of orthodontically induced inflammatory root resorption: A double-blind, split-mouth, randomized controlled clinical trial.

INTRODUCTION: The purpose of this 2-arm-parallel split-mouth trial was to investigate the effect of low-level laser therapy (LLLT) on the repair of orthodontically induced inflammatory root resorption (OIIRR). METHODS: Twenty patients were included in this study, with 1 side randomly assigned to receive LLLT, and the other side served as a sham. Eligibility criteria included need for bilateral maxillary first premolar extractions as part of fixed appliance treatment. OIIRR was generated by applying 150 g of buccal tipping force on the maxillary first premolars for 4 weeks. After the active force was removed, the teeth were retained for 6 weeks. LLLT commenced with weekly laser applications using a continuous beam 660-nm, 75-mW aluminum-gallium-indium-phosphorus laser with 1/e2 spot size of 0.260 cm2, power density of 0.245 W/cm2, and fluence of 3.6 J/cm2. Contact application was used at 8 points buccally and palatally above the mucosa over each tooth root for 15 seconds with a total treatment time of 2 minutes. After 6 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography for primary outcome OIIRR calculations. Subgroup analysis included assessment per root surface, per vertical third, and sites of heaviest compressive forces (buccal-cervical and palato-apical). Randomization was generated using www.randomization.com, and allocation was concealed in sequentially numbered, opaque, sealed envelopes. Blinding was used for treatment and outcome assessments. Two-tailed paired t tests were used to determine whether there were any statistically significant differences in total crater volumes of the laser vs the sham treated teeth. RESULTS: Total crater volumes were 0.746 mm3 for the laser treated teeth and 0.779 mm3 for the sham. There was a mean difference of 0.033 ± 0.39 mm3 (95% CI, -0.21 to 0.148 mm3) greater resorption crater volume in the sham group compared with the laser group; this was not statistically significant (P = 0.705). No harm was observed. CONCLUSIONS: No significant difference was found between LLLT and sham control groups in OIIRR repair.

Low-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.

This study evaluated the biological effects of low-level laser therapy (LLLT) on bone remodeling, tooth displacement and root resorption, occurred during the orthodontic tooth movement. Upper first molars of a total of sixty-eight male rats were subjected to orthodontic tooth movement and euthanized on days 3, 6, 9, 14 and 21 days and divided as negative control, control and LLLT group. Tooth displacement and histomorphometric analysis were performed in all animals; scanning electron microscopy analysis was done on days 3, 6 and 9, as well as the immunohistochemistry analysis of RANKL/OPG and TRAP markers. Volumetric changes in alveolar bone were analyzed using MicroCT images on days 14 and 21. LLLT influenced bone resorption by increasing the number of TRAP-positive osteoclasts and the RANKL expression at the compression side. This resulted in less alveolar bone and hyalinization areas on days 6, 9 and 14. LLLT also induced less bone volume and density, facilitating significant acceleration of tooth movement and potential reduction in root resorption besides stimulating bone formation at the tension side by enhancing OPG expression, increasing trabecular thickness and bone volume on day 21. Taken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model.

The effects of low-level laser therapy on orthodontically induced root resorption.

The aim of this study was to evaluate the preventive and/or reparative effects of low-level laser therapy (LLLT) on orthodontically induced inflammatory root resorption (OIIRR) in rats. Thirty rats were divided into four groups (short-term control (SC), short-term laser (SL), long-term control (LC), long-term laser (LL)). In all groups, the left first molar was moved mesially for 11 days. At the end of this period, the rats in groups SC and SL were killed in order to observe the resorption lacunas and to evaluate whether LLLT had any positive effect on root resorption. The groups LC and LL were remained for a healing period of 14 days in order to observe spontaneous repair of the resorption areas and investigate whether LLLT had reparative effects on root resorption. A Ga-Al-As diode laser (Doris, CTL-1106MX, Warsaw, Poland) with a wavelength of 820 nm was used. In SL group, the first molars were irradiated with the dose of 4.8 J/cm2 (50 mW, 12 s, 0.6 J) on every other day during force application. In LL group, the irradiation period was started on the day of appliance removal and the first molars were irradiated with the dose of 4.8 J/cm2 on every other day for the next 14 days. LLLT significantly increased the number of osteoblasts and fibroblasts, and inflammatory response in SL group in comparison with SC group (P = .001). The amount of resorption did not represent any difference between the two groups (P = .16). In LL group, LLLT significantly increased the number of fibroblasts and decreased the amount of resorption in comparison with LC group (P = .001; P = .02). Both parameters indicating the reparative and the resorptive processes were found to be increased by LLLT applied during orthodontic force load. LLLT applied after termination of the orthodontic force significantly alleyed resorption and enhanced/accelerated the healing of OIIRR. LLLT has significant reparative effects on OIIRR while it is not possible to say that it definitely has a preventive effect.

Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.

The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm(2) over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 ± 0.36 mm) was significantly higher than the second time period (0.24 ± 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.