Percorrer por autor "Kumar, Abhishek"
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- Evaluating the effectiveness of screen-based haptic virtual reality simulators in preclinical prosthodontic crown preparation : mixed methods analysis studyPublication . Odisho, Nabil; Simonian, Ara; Chamoun, Rita; Christidis, Maria; Canales, Giancarlo De la Torre; Kumar, Abhishek; Grigoriadis, AnastasiosBackground: Crown preparation is a technically demanding psychomotor skill in undergraduate dental education. While traditional typodont training is the gold standard, it is resource-intensive and difficult to individualize. Screen-based haptic virtual reality simulators (HVRSs) may provide a pedagogical adjunct to conventional training, but their effectiveness in supporting transfer of skills to physical tooth preparation remains unclear. Objective: This study evaluated whether 3 hours of self-directed HVRS training improved undergraduate dental students’ performance in physical typodont crown preparation compared with no HVRS training. Secondary aims were to examine self-confidence and students’ perceptions of HVRS-based training. Manual dexterity was assessed exploratorily using the Grooved Pegboard Test (GPT). Methods: A mixed methods study was conducted with 44 fifth-semester dental students at Karolinska Institutet. Participants were allocated to an HVRS training group (n=22) or a control group (n=22). The HVRS group completed 3 hours of self-directed HVRS training over 1 week, whereas the control group received no simulator-based training. Both groups then prepared a maxillary right first molar for a monolithic zirconia crown on a phantom head. Crown preparation quality was assessed using PrepCheck, and a blinded examiner scored 8 areas of interest on a 0-3 grading scale. Manual dexterity was assessed using the GPT. Self-confidence was evaluated in both groups using survey items, while perceptions of the HVRS were evaluated only among HVRS group participants. Free-text responses from the HVRS group were analyzed using inductive thematic analysis. Results: The HVRS group achieved a higher mean total preparation score than the control group, but the difference was not statistically significant (11.9 vs 10.9; P=.24). In unadjusted analyses, the HVRS group scored higher for total occlusal convergence (P=.04), but this difference did not remain statistically significant after Bonferroni correction for 8 area-of-interest comparisons. Manual dexterity measured by the GPT improved in both groups, but the control group was significantly faster at baseline (P=.04) and postintervention (P=.001). Self-confidence ratings were broadly similar between groups; very low confidence was reported by 5% (1/20) of respondents in the HVRS group and 18% (4/22) in the control group. Most HVRS group respondents rated the HVRS drilling sensation as having limited comparability with typodont teeth and natural teeth. Qualitative responses suggested that students valued the HVRS for understanding procedural steps, applying theoretical knowledge, and allowing repeated practice, while reported challenges included limited realism, visual-tactile disconnect, and occasional technical issues. Conclusions: Three hours of self-directed HVRS training did not significantly enhance overall crown preparation quality on typodont teeth or improve students’ general self-confidence. There is preliminary indication that HVRS could assist in mastering specific geometric parameters like total occlusal convergence. Future randomized controlled trials with stratified baseline dexterity and larger sample sizes are required to determine the optimal role of HVRS in dental education.
- Impact of chewing muscle anesthesia on masticatory performance in healthy participantsPublication . Flores, Dyanne Medina; Karlsson, Tilda; Canales, Giancarlo De La Torre; Kaspo, Natalie; Malmström, Clara; Messerer, Sara; Kumar, Abhishek; Svedenlöf, Johanna; Conti, Paulo Cesar Rodrigues; Christidis, Nikolaos; Grigoriadis, AnastasiosThe impact of the muscle spindles in the masticatory performance remains elucidated. This study aimed to investigate the impact of local anesthesia in the jaw-closing muscles on masticatory performance in healthy participants. Thirty healthy pain-free volunteers underwent in two rounds of chewing tasks involving two types of viscoelastic candies and a two-coloured chewing gum. Lidocaine (3.0 mL) was injected into a total of six points in the masseter and temporalis muscles bilaterally for the second round. Pain intensity, fatigue, the number and area of particles, and the degree of mixing of the chewing gum were assessed at baseline and after each round of chewing. The number of candy particles after injection of lidocaine, was significantly lower (33%) for women compared to the results without anesthesia (p < 0.05). There was no significant difference in the variance of hue of the two-coloured chewing-gum when comparing values before and after anesthesia. None of the participants experienced any pain during the experiment. However, self-reported fatigue increased during the second round, i.e., after anesthesia, with significantly higher values observed at the final assessment point. (p = 0.029). Local anesthesia of the jaw-closing muscles appears to impair the masticatory function in women, leading to reduced efficiency in food comminution compared to normal mastication. The observed sex differences suggest that women may be more vulnerable to neuromuscular control alterations following sensory alterations.
- Temporalis muscle changes following botulinum toxin A injections in masseter hypertrophy patients : a randomized triple-blinded trialPublication . Nobre, Bryanne B. de Souza; Machado, Luciana de Oliveira Resende; Poluha, Rodrigo Lorenzi; Câmara-Souza, Mariana Barbosa; Carbone, Ana Claudia; Almeida, Andre Mariz de; Grigoriadis, Anastasios; Kumar, Abhishek; Canales, Giancarlo De la TorreBackground: This study aimed to elucidate the effects of botulinum toxin A (BoNT-A) treatment for patients diagnosed with masseter hypertrophy on the temporalis muscle, with a particular focus on assessing alterations in muscle thickness, electromyographic (EMG) activity, and the development of muscle pain. Methods: The present randomized triple-blinded clinical trial enrolled 26 female participants aged between 25 and 50 years complaining about masseter hypertrophy. Participants received 75U of BoNT-A (abobotulinumtoxinA) in both masseter muscles and after three months were randomized to receive a second treatment session of saline solution (S-BoNT-A) or BoNT-A (M-BoNT-A). Longitudinal assessments included temporalis muscle thickness through ultrasound, EMG activity, subjective pain, and masseter prominence severity after one, three, and six months of the first injection session. Muscle thickness, EMG, and subjective pain were analysed using two-way ANOVA with repeated measures and post hoc Sidak test, and for masseter prominence severity, Friedman and Mann–Whitney tests were used. Results: Regarding inter-group comparisons, a higher muscle thickness (p < 0.02) and a higher EMG activity (p < 0.01) were found in the M-BoNT-A group at the 6-month follow-up. For subjective pain assessments, inter-group comparisons showed a higher prevalence of painful regions in M-BoNT-A group at the 6-month follow-up (p < 0.02). No significant differences were found in masseter prominence severity at the 6 months assessment between groups. Conclusion: BoNT-A treatment for masseter hypertrophy lead to structural and functional changes in the temporalis muscle, presenting higher changes after multiple injections of this treatment.