Effect of intervertebral disc degeneration on the stomatognathic system function in adults.

OBJECTIVE: To analyze the electromyographic activity (EMG) and thermographic patterns of the masseter and temporalis muscles and pressure of the orofacial tissues in individuals with intervertebral disc degeneration (IDD). METHODS: This study had two distinct groups: with IDD (n = 16) and controls (n = 16). EMG at rest, protrusion, right and left laterality, and maximum voluntary contraction were evaluated. Tongue, orbicularis oris, and buccinator muscles pressures were measured by Iowa Oral Performance Instrument. The thermographic patterns were analyzed using infrared thermography. RESULTS: Comparisons between groups showed significant differences regarding at rest [right (p = 0.05) and left (p = 0.05) masseter and right temporal (p = 0.05)], orofacial tissue pressure [tongue (p = 0.001), orbicularis oris (p = 0.01), and buccinator (p = 0.0001)], but no significant differences for the thermographic patterns. CONCLUSION: IDD modifies the functionality of the craniomandibular complex, influencing the performance of the stomatognathic system.

Intervertebral Disc Degeneration: Functional Analysis of Bite Force and Masseter and Temporal Muscles Thickness.

Intervertebral disc degeneration is a pathological condition associated with the intervertebral disc and is related to functional alterations in the human body. This study aimed to evaluate the maximum molar bite force and masseter and temporal muscles thickness in individuals with intervertebral disc degeneration. Thirty-two individuals were divided into two groups: those with degeneration of intervertebral discs (n=16) and those without degeneration (n=16). The maximum molar bite force (on the right and left sides) was measured using a dynamometer. Masseter and temporal muscle thickness during mandibular task rest and dental clenching in maximum voluntary contraction were analysed using ultrasound. Significant differences in the left molar bite force (p=0.04) were observed between the groups (Student's t-test, p<0.05). The intervertebral disc degeneration group had a lower maximum molar bite force. No significant differences in muscle thickness were observed between the masseter and temporal muscles in either group. However, based on clinical observations, the group with intervertebral disc degeneration presented less masseter muscle thickness and greater temporal muscle thickness in both mandibular tasks. Degenerative disease of the intervertebral discs promoted morphofunctional changes in the stomatognathic system, especially in maximum molar bite force and masticatory muscle thickness. This study provides insight into the interaction between spinal pathology and the stomatognathic system, which is important for healthcare professionals who treat patients with functional degeneration.

Repeatability Study of Angular and Linear Measurements on Facial Morphology Analysis by Means of Stereophotogrammetry.

The aim of this study was to analyze the repeatability in a stereophotogrammetry digital system used for the evaluation of facial morphology. Thirty healthy Brazilian, 18 to 45 years old (26.71 ±â€Š6.53), had 11 reference landmarks marked on their faces by the same examiner and were photographed with an interval of 1 week by the VECTRA M3. Nine angular measurements (nasolabial, mentolabial, nasofrontal, maxillofacial, nasal, maxillary, mandibular, facial convexity, full facial convexity) and 2 linear measurements (middle facial height and lower facial height) were taken. Repeatability was analyzed by the mean absolute differences, relative error of magnitude, technical error of measurement, intraclass correlation coefficient, and Bland-Altman analysis. Paired t test sought any systematic errors between the acquisitions. Associations among body mass index, age, and the error in the measurements were made using the Pearson correlation coefficient. For the technical error of measurement, the nasolabial and mentolabial angles showed values >2° (clinical limit set for this study). For the relative error of measurement, most of the measures were rated between good and excellent. The maxillofacial angle was only moderate. There was a systematic error for middle facial height. The nasolabial, mentolabial, facial convexity, full facial convexity, maxillofacial, and nasofrontal angles presented intraclass correlation coefficient values rated as excellent. The relationship between age/body mass index and the error found between measurements was not confirmed. The nasolabial and mentolabial angles should be interpreted with caution due to the variability showed. The results found stereophotogrammetry to be repeatable, giving accurate measures within the references established for this study.

Analysis of adhesive interface in root canals irradiated by Er,Cr:YSGG laser after luting a fiber post.

This study evaluated the effect of Er,Cr:YSGG laser on the root canal dentin after luting a fiber post. Twenty-four bovine teeth roots were prepared using NiTi instruments and filled with Sealer 26 and gutta-percha. Post spaces were prepared and roots were distributed according to dentin treatment (n = 8): 2.5%NaOCl (group control), Er,Cr:YSGG laser (1.5 W, 20 Hz, 20 s) (group test 1) or 2.5%NaOCl + Er,Cr:YSGG laser (group test 2). Fiber posts were luted using adhesive cement (Rely X U200, 3M) and roots were prepared to confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The morphology of interface, thickness of cement, and the gaps and tags were analyzed. Non-parametrical data for thickness of cement were submitted to Friedman and Kruskall-Wallis tests (α = 0.05) and parametrical data for gaps to ANOVA (α = 0.05). CLSM of the cement thickness and gaps revealed no significant difference in surface treatment (NaOCl, Er,Cr:YSGG laser and NaOCl + Er,Cr:YSGG laser) (p > .05) and canal thirds (cervical, middle, and apical) (p > 0.05). SEM showed tags and a residual layer of cement adhered to dentin, mainly in laser-irradiated specimens. The pretreatment of root canal with Er,Cr:YSGG laser previously to luting the fiber post with a self-adhesive cement did not influence the cement thickness and gaps but affected the dentin interaction.