Evaluation of the effects of chronic qat chewing on lateral pterygoid muscle using MRI.

Objective: This study explored the effect of qat chewing (QC) on the lateral pterygoid muscle (LPM), using magnetic resonance imaging (MRI).Methods: Forty qat chewers (QG), divided into three subgroups, according to duration of QC, and 20 non-qat chewers (NQG) were included. MRI sections were obtained to assess hypertrophy and atrophy of the superior belly (SB) and inferior belly (IB) of the LPM on the chewing and contralateral non-chewing side.Results: There was a significantly higher prevalence of atrophy of the IB (p < 0.001) and hypertrophy of the SB and IB (p = 0.002) in the QG. Hypertrophy of SB and IB was marked (p = 0.001) on the chewing side. Conversely, SB atrophy was marked on the non-chewing side (p = 0.003). MRI demonstrated a positive correlation between LPM alterations and the duration of QC in subgroup analysis.Conclusion: Unilateral QC might be a cause of LPM alterations.

An MRI evaluation of the effects of qat chewing habit on the temporomandibular joint.

OBJECTIVE: The aim of this study was to investigate the effects of the qat chewing habit on the temporomandibular joint by using magnetic resonance imaging. STUDY DESIGN: Sixty patients were included: a study group (40 qat chewers) and a control group (20 nonchewers). On the basis of qat chewing habit duration, the study group was subdivided into 3 further subgroups: subgroup I (5-10 years), subgroup II (11-15 years), and subgroup III (>15 years). Data on qat chewing habit were recorded, and a standardized clinical examination was performed. Bilateral oblique sagittal magnetic resonance imaging sections were obtained to evaluate disk displacement, osteoarthritis, and joint effusion. RESULTS: Clicking and pain were diagnosed in 72.5% and 65% of study group patients, respectively. Significant differences were discovered between the study group and the control group in osteoarthritis and joint effusion (P= .003 and .002, respectively). With regard to qat chewing habit duration, there were differences between study subgroup II and subgroup III versus control group in osteoarthritis (P= .040 and .001, respectively) and the 3 study subgroups versus control group in joint effusion (P= .026, .004, and .001, respectively). Significant correlations were found between osteoarthritis and clicking (P= .006) and muscle pain (P ≤ .044), and between joint effusion and temporomandibular joint pain (P = .006) and muscle pain (P ≤ .014). CONCLUSIONS: Qat chewing habit may be a risk factor for temporomandibular joint disorders with high percentages of osteoarthritis and joint effusion.

Evaluation of different low-dose multidetector CT and cone beam CT protocols in maxillary sinus imaging: part I-an in vitro study.

OBJECTIVES: This in vitro study aimed to assess radiation dose and image quality of different low-dose multidetector CT (MDCT) and CBCT imaging protocols in comparison with the standard MDCT protocol for maxillary sinus imaging. METHODS: Effective dose (E) and image quality of 10 MDCT (changing effective milliampere second starting from 141.3 EmAs to 20 EmAs) and 3 CBCT protocols (changing milliampere second and voxel size) were assessed throughout scanning an anthropomorphic head and neck Alderson Rando phantom. E values were calculated using thermoluminescent dosemeters (TLDs) fixed at 6 sensitive organs (14 sites) on the Rando phantom. Image quality was assessed objectively (by calculating the standard deviation values of the radiographic density of water) and subjectively (by assessing the diagnostic image quality using a four-graded scale: 1 = very good, 2 = good, 3 = acceptable and 4 = unacceptable). RESULTS: Two MDCT protocols (120 kV/32 EmA and 120 kV/25 EmA) had lower radiation doses with statistically significant differences (p < 0.001) compared with that of the standard MDCT protocol (120 kV/141.3 EmA), and they preserved a good diagnostic image quality. One CBCT protocol (120 kV/20 mA) had a reasonable radiation dose and good image quality. There were no statistically significant differences between the above-mentioned lower dose MDCT and CBCT protocols (p > 0.05) with respect to the radiation dose and image quality. CONCLUSIONS: The low-dose MDCT and CBCT protocols are viable methods for maxillary sinus examination as evaluated using the above-mentioned phantom that yield a good diagnostic image quality using E approximately 7 and 11 times lower than that of the standard MDCT, respectively. These findings were evaluated in the in vivo part of this project.