Publications

When two probes are flashed at different times within a moving frame, they can be perceived as dramatically separated from each other even though they are at the same location in the display. This effect suggests that we perceive object position relative to the surrounding frame even when it is moving (Özkan et al., 2021). Here, eight experiments reveal new properties of this frame effect. First, the influence of the frame on the perceived probe positions extends beyond its bounding contours by several degrees of visual angle, both in the direction of the frame's motion and orthogonal to it. It is also undiminished when the probes and the frame are in different depth planes. However, the influence of the frame's motion shows no extension in time-there is no effect on probes presented after the frame is removed and none retroactively before the frame appears either. The frame effect is also driven primarily by the displacement of the frame, not by its motion signals: the effect is stronger for moving bounded frames compared with moving unbounded random dot textures. When the bounded region has an internal texture that moves with or against the frame's motion or remains static, it is the displacement of the frame that produces the perceived position shifts of the probes, and the effect of the internal motion is mostly suppressed. The frame's influence is unaffected by whether the motion is self-initiated or not and does not diminish in strength across 2 hours of testing.

Blinks serve not only to maintain ocular lubrication, but may also contribute to visual processing, although their functional role remains poorly understood. Recent research has shown that spontaneous and voluntary blinks serve distinct functions in perceptual competition involving binocular interactions (Sato & Kimura, 2024). To disentangle the retinal and extra-retinal contributions of blinking, this study investigated how different types of blinks affect perceptual alternation using a bistable apparent motion stimulus where the perceived motion direction alternates between vertical and horizontal. Results showed that instructed (i.e., voluntary) blinks facilitated perceptual alternation, whereas spontaneous blinks did not. The time to perceptual alternation was longer on spontaneous-blink trials, but these blinks showed no clear temporal association with the alternation. Physical blackouts simulating blinks also did not affect perceptual alternation. However, these same blackouts did modulate it when susceptibility to perceptual alternation was high, suggesting that retinal transients have a limited but condition-dependent effect. Moreover, the lack of modulation from instructed key presses suggests that extra-retinal self-motion signals per se cannot account for the effect. Notably, instructed eye widenings, which do not involve eyelid closure, also facilitated perceptual alternation. Taken together, these results suggest that the facilitatory effects of voluntary blinking primarily reflect extra-retinal signals associated with voluntary eyelid movements.

AIM: To assess the perceived smile esthetics and psychosocial impact of orthodontic treatment in individuals with definite malocclusion.

MATERIALS AND METHODS: A cross-sectional observational study was conducted on 333 Indian individuals aged 12-40 years with untreated malocclusion of various types. A validated questionnaire based on the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) was used, covering eight domains: Self-confidence, social impact, esthetic concerns, psychological impact, speech impairment, functional limitations, matrimonial concerns, and career concerns. Each of the 16 items was scored on a 5-point Likert scale. Data were statistically analyzed using SPSS (Version 30.0), with significance set at p < 0.05. Reliability was assessed using Cronbach's α.

RESULTS: The study sample comprised n = 333 Indian individuals between 12 and 40 years of age. The overall questionnaire reliability was acceptable (α = 0.751). Self-confidence concerns showed no gender difference (males: 72, 31.6%; females: 151, 34.5%; p = 0.162). Esthetic concern was higher in males (91, 39.9% with no concern) than in females (243, 55.5%; p = 0.001). Social impact was reported more by males (98, 43.0%) than by females (110, 25.1%; p < 0.001). Matrimonial concerns were greater in males (28, 12.3% severe) compared to females, where most (270, 61.6%) had no concern (p < 0.001). Functional difficulty was more frequent in males (23, 10.1% severe) vs females (18, 4.1%), with 300 females (68.5%) unaffected (p < 0.001). Career, speech, and psychological concerns were also significantly higher among males, while females more often reported no concern across domains.

CONCLUSION: The study demonstrates that individuals with definite malocclusion perceive a substantial psychosocial and esthetic burden even before undergoing orthodontic treatment. Participants commonly reported diminished self-image, lower social confidence, and emotional distress, indicating that malocclusion affects more than just dental function. These perceptions were key motivators for seeking orthodontic intervention, reflecting the strong influence of appearance- and confidence-related concerns, alongside functional needs, on their decision to pursue treatment.

CLINICAL SIGNIFICANCE: Malocclusion affects not only dental alignment but also mental well-being, self-esteem, and social interactions. This study highlights the importance of assessing psychosocial impacts in untreated individuals to establish meaningful pretreatment benchmarks. Orthodontic care emerges as a transformative intervention that enhances self-image, emotional stability, and overall quality of life. Incorporating patient-reported outcomes into routine assessment allows for more holistic and personalized treatment planning. How to cite this article: Sinha R, Nagar S, Kumar A, et al. Perceived Smile Esthetics and Psychosocial Impact of Orthodontic Treatment in Individuals with Definite Malocclusion: A Cross-sectional Study. J Contemp Dent Pract 2026;27(1):44-50.

AIM: To compare the nano-surface characteristics and antimicrobial efficacy of calcium hydroxide-coated stainless steel crowns (SSCs) and zirconia crowns using atomic force microscopy (AFM) and agar diffusion method.

MATERIALS AND METHODS: An in vitro study was conducted using 10 crowns, divided into two groups: Five calcium hydroxide-coated zirconia crowns (Group I) and five calcium hydroxide-coated SSCs (Group II). Both crown types were uniformly coated with calcium hydroxide nanoparticles. Nanosurface topography was assessed using AFM, and antimicrobial activity against Streptococcus mutans and Lactobacillus species was evaluated using the agar well diffusion method. Antimicrobial plates were incubated for 24 hours before zone measurement. Data were analyzed using the Mann-Whitney U test, with p < 0.05 considered statistically significant.

RESULTS: Atomic force microscopy analysis revealed significantly higher nanoscale surface roughness in zirconia crowns compared to SSCs. Antimicrobial testing demonstrated markedly larger zones of inhibition for zirconia crowns against S. mutans and Lactobacillus compared to SSCs, statistically indicating highly significant differences.

CONCLUSION: Calcium hydroxide-coated zirconia crowns exhibit superior nanoscale roughness and enhanced antimicrobial efficacy compared to calcium hydroxide coated stainless steel crowns.

CLINICAL SIGNIFICANCE: This study addresses the clinical need for restorative options that not only restore form and function but also actively contribute to caries prevention in high-risk patients. Enhancing the antibacterial performance of preformed crowns through calcium hydroxide coatings may help limit bacterial colonization at crown margins, reduce the incidence of secondary caries, and support better longevity of both zirconia and SSCs. How to cite this article: Seth S, Ravikumar R. Comparison of Nanosurface Evaluation and Antimicrobial Efficacy of Calcium Hydroxide-Coated Stainless Steel and Zirconia Crowns in Pediatric Dentistry: An Atomic Force Microscopic Study. J Contemp Dent Pract 2026;27(1):37-43.

AIM: To evaluate and compare the effects of micro-osteoperforations (MOPs) and injectable platelet-rich fibrin (I-PRF) on external apical root resorption (EARR) during maxillary canine retraction using a split-mouth prospective study design.

MATERIALS AND METHODS: Twenty orthodontic patients (mean age 22.8 ± 2.7 years) who required first premolar extractions bilaterally were recruited. In each subject, one quadrant was randomly assigned to MOP and the contralateral quadrant to I-PRF. All patients underwent fixed appliance therapy with a pre-adjusted edgewise system, and maxillary canines were retracted with NiTi closed-coil springs delivering 150 gm of force. Micro-osteoperforations were performed at the initiation of retraction, whereas I-PRF was injected monthly. To measure changes in root length, cone-beam computed tomography (CBCT) images of the patients were taken both prior to and following full canine retraction (T0 and T1, respectively). Statistical analysis was completed using unpaired and paired t-tests (p < 0.05).

RESULTS: Both groups demonstrated significant root length reduction after retraction (p < 0.05). The mean EARR in the MOP group was 1.21 ± 0.25 mm, while the I-PRF group showed 1.00 ± 0.10 mm of resorption. Despite the MOP group's somewhat higher resorption, there were no clinically noteworthy distinctions between the two categories (p > 0.05).

CONCLUSION: Micro-osteoperforations and I-PRF are both effective adjuncts for facilitating orthodontic tooth movement (OTM); however, both approaches are associated with measurable root resorption. There is no statistically significant difference observed between the two techniques in terms of minimizing EARR.

CLINICAL SIGNIFICANCE: While MOPs and I-PRF can shorten treatment duration, clinicians should remain cautious of their potential to induce root resorption. Injectable PRF may offer additional biological benefits owing to its regenerative properties, but long-term studies with larger samples should be done before definitive clinical recommendations are suggested. How to cite this article: Niranjane P, Taori KP, Kolhatkar K. Evaluation of the Effects of Micro-osteoperforation and Injectable Platelet-rich Fibrin on the External Root Resorption: A Split-mouth Prospective Study. J Contemp Dent Pract 2026;27(1):78-82.

AIM: This study aims to evaluate the probable impression of the tongue forces on the posterior mandibular dentoalveolar structure through the assessment of the reflected stress distribution and the possible resultant displacement by finite element analysis on the mandibular model.

MATERIALS AND METHODS: The AutoCAD (2010) software was used to design the three-dimensional mandibular study model for finite element analysis. A force of 2, 90, and 500 g/cm2 that represents the forces expressed by the tongue during the normal rest posture, the normal function, and abnormal function, respectively, is applied perpendicularly to the lingual aspect of the mandibular model posterior portion.

RESULTS: Higher displacement values in the three axes of space X, Y, and Z are complementary to high von Mises stresses seen in abnormal tongue function state, and lowest for the normal rest posture, with normal function state in between.

CONCLUSION: This study showed that abnormal lingual habits possibly have an adverse effect on the mandibular posterior structure. It may lead to abnormal deviation in the form and position during growth. How to cite this article: Alsultan MMH, Al Zubaidi SH, Alsaleem NR. Abnormal Tongue Behavior with Its Imaginable Influence on the Posterior Mandibular Dentoalveolar Structure. J Contemp Dent Pract 2026;27(1):27-32.