A randomized controlled trial evaluating the effect of two low-level laser irradiation protocols on the rate of canine retraction.

The objective of this study was to evaluate the canine retraction rate with two low-level laser therapy (LLLT) irradiation protocols, involving both a high and a low application frequency. Twenty patients were randomly divided into two equal groups. In Group A, one side of the maxillary arch randomly received LLLT on days 0, 3, 7, 14, and every 2 weeks thereafter, whereas in Group B, one side received LLLT every 3 weeks. Tooth movement was checked every three weeks since the onset of canine retraction, over the 12-week study period. Moreover, Interleukin-1ß (IL-1ß) levels in the gingival crevicular fluid were assessed. Results revealed a significant increase in the canine retraction rate on the laser sides of groups A and B, in comparison with the control sides (p < 0.05), with no significant differences reported between the laser sides in both groups (p = 0.08-0.55). Also, IL-1ß levels were significantly higher on the laser sides of both groups, in comparison with the control sides (p < 0.05). Therefore, LLLT can effectively accelerate tooth movement, with both frequent and less frequent applications, which is attributed to an enhanced biological response as reflected by the elevated IL-1ß levels on the compression sides.

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 .

Association between the FGFR1 rs13317 single nucleotide polymorphism and orbitale-nasion depth based on cephalometric images.

The fibroblast growth factor receptor 1 (FGFR1) gene plays an important role in craniofacial morphogenesis. In our previous study, an association between FGFR1 single nucleotide polymorphisms (SNPs) and craniofacial morphology was demonstrated in Japanese and Korean subjects. The present study aimed to evaluate the relationship between a common FGFR1 SNP (rs13317) with craniofacial morphology, increasing the number of measurements and examining Egyptian subjects (n = 191) in addition to the Japanese (n = 211) and Korean (n = 226) subjects. Genotyping for rs13317 was performed using the TaqMan assay, and its associations with 81 craniofacial measurements derived from lateral and posteroanterior cephalograms were analyzed by multiple regression analysis controlling sex and facial size. The results from each of the populations were then statistically combined. In the Egyptian subjects, rs13317 was significantly associated with the nasion-orbitale depth (P = 0.00040), and a suggestive association was also observed in the Japanese (P = 0.037) and Korean subjects (P = 0.045). The combined analysis revealed that only the nasion-orbitale depth showed a significant association (P = 0.000062) and that several measurements showed a suggestive association. Our results strongly indicate that rs13317 is associated with a smaller depth between the nasion and orbitale, representing a relative protrusion of the cheekbones and retrusion of the nasal root. A similar characteristic is also observed in individuals with Pfeiffer syndrome, which is caused by a dysfunctional FGFR1 mutation.

Contribution of FGFR1 Variants to Craniofacial Variations in East Asians.

FGFR1 plays an important role in the development of the nervous system as well as the regulation of the skeletal development and bone homeostasis. Mutations in FGFR1 genes affect skull development, specifically suture and synchondrosis, resulting in craniosynostosis and facial abnormalities. We examined subjects with normal skull morphology for genetic polymorphisms that might be associated with normal craniofacial variations. Genomic DNA was obtained from 216 Japanese and 227 Korean subjects. Four FGFR1 SNPs, namely, rs881301, rs6996321, rs4647905, and rs13317, were genotyped. These SNPs were tested for association with craniofacial measurements obtained from lateral and posteroanterior cephalometries, in which principle component analysis was performed to compress the data of the craniofacial measurements. We observed that SNPs rs13317 and rs6996321 were correlated with the overall head size and midfacial development, indicating that FGFR1 SNPs played crucial roles in the normal variation of human craniofacial morphology. Subjects with the derived alleles of SNPs rs13317 and rs6996321 had a small face and a facial pattern associated with a retruded midface and relatively wide-set eyes. These facial features were similar to but were milder than those of individuals with Pfeiffer syndrome, which is caused by a dysfunctional mutation in FGFR1.

Molar Intrusion in Open-bite Adults Using Zygomatic Miniplates.

The aim of this study is to evaluate the skeletal, dental and soft tissue changes that arise after intrusion of the maxillary molars using zygomatic miniplates in adult skeletal anterior open bite patients. In addition to measuring the amount and rate of molar intrusion; with special emphasis on changes in the axial inclination of the intruded molars. The study group was composed of 13 anterior open bite patients (mean age 18 years, 8 months ± 2 years, 2 months) with posterior dentoalveolar excess. Mini-plates were placed in the zygomatic buttress bilaterally. The upper arch was segmentally leveled and a double Trans-Palatal Arch (TPA) was bonded. Closed NiTi coil spring was placed bilaterally between the book of the mini-plate just mesial and distal to the first molar buccal tube applying intrusive force of 450 gper side. Lateral and posteroanterior cephalograms were taken before intrusion (T1: post upper segmental leveling) and after intrusion (T2). Comparison between means before and after the intrusion was done using Wilcoxon Signed Ranks test (WSRT). Mandibular autorotation followed the molar intrusion, SNB and SN-Pog angles significantly increased while the ANB, MP-SN angle and N-S-Gn angle significantly decreased. The mean amount of accomplished molar intrusion was 3.1mm ± 0.74mm, with a rate of 0.36mm per month ± 0.08mm per month and a bite closure of 6.55mm ± 1.83mm. There was no significant buccal tip in the right and left molars upon intrusion. Conclusion: Miniplates zygomatic anchorage can be used effectively for skeletal open bite correction through posterior dento-alveolar intrusion. Intrusion of the posterior teeth with skeletal anchorage induced counterclockwise rotation of the mandible and, as a consequence, corrected the anteroposterior intermaxillary relationship with a dramatic improvement in the facial soft tissue convexity.