A comparative finite element analysis of titanium, poly-ether-etherketone, and zirconia abutment on stress distribution around maxillary anterior implants.

Background: The aim of this study was to investigate the influence of abutment material, alveolar bone density, and occlusal forces on stress distribution around maxillary anterior implants. Materials and Methods: An in-vitro study was conducted. The maxillary anterior implant was modeled using a three-dimensional finite element model in D2 and D3 bones with three different abutment materials: titanium, zirconia, and poly-ether-ether ketone (PEEK). Von Mises stress was evaluated after the application of vertical and oblique loads of 100 N, 175 N, and 250 N. Statistical analysis was done by Friedman-Wilcoxon signed-rank test, Mann-Whitney U test, and Kruskal-Wallis test. The probability value <0.05 is considered a significant level. Results: Stress distribution around D3 bone was higher than D2 bone in all the abutment materials with greater values seen in oblique load than vertical load with insignificant difference (P > 0.05). Statistically insignificant stress values were seen greater in PEEK than titanium or zirconia abutment (P > 0.05). A statistically significant difference was observed between 100 N and 175 N of load (P < 0.05). Conclusion: PEEK, zirconia, and titanium as abutment material in the anterior region showed similar properties. The stress on the bone was proportionately increased during the vertical and oblique loads suggesting the influence of mechanical load in crestal bone loss rather than the type of abutment material.

Comparative evaluation of simvastatin gel in enhancing peri-implant osteoblastic activity during the Osseo integrative phase using Bone scintigraphy: A prospective case-control double blinded study.

BACKGROUND: Simvastatin (SMV), a lipid lowering drug, can modulate the process of bone regeneration at the molecular and cellular levels. Its effect on the osseointegration of implants has been studied extensively on animals with assuring results with limited research on human subjects. AIM: To estimate the effect of simvastatin gel in the osseointegration of dental implants using bone scintigraphy, Materials and Methods: 20 participants with missing mandibular first molars and D2 type bone were assigned equally to Group A receiving 1.2% simvastatin and Group B receiving Placebo gels during the placement of implants. The participants were subjected to bone scintigraphy to determine the osteoblastic activity at baseline, 30th day and 90th day after implant placement. RESULTS: Group A revealed a significant increase in osteoblastic activity between baseline, day 30 and 90 (P<.05) with a higher mean of 100.06±21.644% on day 30. Group B revealed a significant increase in osteoblastic activity only between baseline and day 30, and baseline and day 90 (P<.05) whereas there was no difference between day 30 and 90 (P>.05) with a higher mean of 79.20±18.255% on day 30. Bivariate analysis at different time periods revealed a significant difference between groups A and B on day 30. CONCLUSION: Implants placed with 1.2% simvastatin gel showed enhanced osteoblastic activity on the fourth week of implant placement, indicating faster rate of osseointegration at an early stage.

Comparative Effect of Rehabilitation with Three Different Treatment Modalities for a Single Missing Molar on Brain Activity-A Prospective Clinical Study.

PURPOSE: To evaluate and compare the changes in brain activity for individuals with a single missing mandibular molar replaced with a removable dental prosthesis (RPD) and a fixed tooth-supported implant prosthesis in the static and postmasticatory phases. MATERIALS AND METHODS: In total, 24 patients with a unilateral missing mandibular first molar were rehabilitated with a removable dental prosthesis and divided into two groups of 12 each; Group A was rehabilitated with implants and Group B with 3-unit tooth-supported fixed partial dentures (FPDs). An electroencephalogram (EEG) was taken during the three phases of assessment: (1) before insertion of any prosthesis (N0), (2) after insertion of an RPD (N1), and (3) after cementation of an FPD or implant crown (F2). The effect of bite force with RPD (N1M) and FPD or implant prosthesis (F2M) on alpha waves was evaluated by recording EEG immediately after chewing gum for 30 seconds. RESULTS: The improvement of the amplitude of alpha waves before and after prosthesis insertion showed a significant difference between Group As and B (P < .05) with the highest mean values of 158.3 µV, 147.9 µV, and 182.1 µV occurring in pairs F2-N0, F2-N1, and F2M-N1M, respectively, for Group A. Similarly, for the power of alpha waves between group A and B, a statistically significant difference (P < .05) with the highest mean values of 30.3 dB, 28.9 dB, 36.9 dB, and 11.2 dB in pairs F2-N0, F2-N1, F2M-N1M, and F2M-F2 ,respectively, was observed for Group A. There was no statistically significant increase in pair N0-N1 (P > .05). CONCLUSIONS: Replacement of a single missing tooth enhanced brain activity and was highest with an implant-supported crown. Int J Prosthodont 2023;36:563-569.

Early Implant Bone Loss in the Preprosthetic Phase: A Retrospective Study.

Initiation of the inflammatory response begins with the surgical placement of an implant that stimulates bone remodeling. The occurrence of crestal bone loss during submerged healing affects the prognosis of an implant. Hence, this study was conducted to estimate the early implant bone loss during the preprosthetic phase on bone level implants placed equicrestally. This retrospective observational study included evaluation of crestal bone loss around 271 two-piece implants placed in 149 patients from the archived postsurgical (P1) and preprosthetic (P2) digital orthopantomographic records using MicroDicom software. The outcome was categorized based on (1) sex (male or female), (2) time of implant placement (immediate [I] vs conventional [D]), (3) duration of healing period before loading (conventional [T1] vs delayed [T2]), (4) region of implant placement (maxilla [M1] vs mandible [M2]), and (5) site of implant placement (anterior [A] vs posterior [P]). To find the significant difference between the bivariate samples in the independent groups, an unpaired sample t test was used. The average marginal bone loss during the healing phase was 0.56 ± 0.573 mm in the mesial region and 0.44 ± 0.549 mm in the distal region of the implant, with a statistically significant difference (P < .01). There was no statistically significant difference in crestal bone level with the (1) sex of the patient (male or female), (2) type of implant placement (I or D), (3) time of implant loading (T1 or T2), (4) region of implant placement (M1 or M2), or (5) site of implant in the arch (A or P) (P > .05). An average of 0.50 mm crestal bone loss occurred in the peri-implant region during the preprosthetic phase. We found that the delayed placement of an implant and a delay in the healing period would further increase the early implant bone loss. The difference in the healing period did not alter the outcome of the study.

Evaluation of Changes in the Mechanical Properties of O-Ring in One Piece and Two Piece Ball Retained Implant Supported Overdentures: A Three-Year Retrospective Study.

The O-rings in ball retained overdentures deteriorate with time and need replacement to restore the retentive quality. We evaluated retrospectively the mechanical properties of O-rings after 3 years in function in 1 and 2-piece implant-supported overdentures. The O-rings were retrieved from one-piece (Myriad snap, Equinox-Straumann, 3.3 × 13 mm) and 2-piece (Neo Biotech, 3.3 × 13 mm) implant-supported overdenture patients. A total of 16 pairs of matrices were tested for wear, type of damage, and elasticity using Pin on Disc method, USB Digital Camera in 30× zoom and Universal Tensile Machine, respectively. The statistical analysis for independent groups were done with the Mann-Whitney U test. Assessment of used O-rings showed 84% more wear in the 2-piece system with an abrasive type of damage while 46% wear in the 1-piece system with a compressive type of damage. The O-rings in 1-piece system showed increase in elongation and maximum displacement to 2% and 7%, respectively, whereas the 2-piece system showed decrease in elongation and maximum displacement by 13% and 6%, respectively. In 1-piece system, the loss of retention was more with slow wear rate, and in 2-piece system, the wear resistance of O-rings decreased due to increased stiffness. Further studies to evaluate the changes in O-ring with increased sample size and at interval 1 year will pave way for insight into the progressive changes in the mechanical properties of an O-ring.

Body image perception and its psychological influence on prosthesis satisfaction.

AIM: To identify the body image perception of an individual utilising figure rating scale and assess its psychological influence in altering the prosthetic satisfaction. METHODS: One hundred five of 140 participants were categorised into Groups I, II and III according to their body image satisfaction. Pre- and posttreatment denture satisfaction questionnaires, and pretreatment Big Five personality, Life Satisfaction questionnaires were given to the participants in each group. Analysis of variance (ANOVA) and Tukey post hoc tests assessed the significant relation between the groups. RESULTS: Body image satisfied group (I) was highly contented with the prosthetic treatment (46.90), while body image dissatisfied groups (II and III) had lower denture satisfaction scores (36.80 and 29.70). Neurotic score was significantly different in pairs; Groups I and III, and Groups II and III (P < .001), with high mean for Group III (75.30). The agreeable score was significantly different in Groups I and II (P < .05), with a high mean for Group I (83.60). Life Satisfaction score was significantly different in pairs; Groups I and III, and Groups I and II (P < .001), with a high mean for Group I (30.60). CONCLUSION: The individual's perception of body image had an effect on their denture satisfaction level, and figure rating scale would help in identifying the psychological profile of the patient.

Comparative Evaluation of Changes in Brain Activity and Cognitive Function of Edentulous Patients, with Dentures and Two-Implant Supported Mandibular Overdenture-Pilot Study.

BACKGROUND: The relationship between brain and prosthesis was previously assessed either by improving denture function or in fixed implant retained, wherein brain function was assessed only after crown placement. PURPOSE: To prospectively analyze the changes in brain activity and cognitive function of completely edentulous patients in edentulous state, with dentures and two-implant supported mandibular overdenture before and after loading, along with the effect of mastication in the change - a pilot study. MATERIALS AND METHOD: Ten completely edentulous (CE) non-denture wearers were selected. The mandibular prosthesis was loaded with two 3.3 mm × 13 mm myriad snap fit implants. To assess the brain activity and cognitive function, Electroencephalogram (Neurofax EEG 1000 Ver 05-90, Nihon Kohden corporation, Tokyo, Japan) and Mini-Mental State Examination (MMSE) questionnaire, respectively, were taken during the process of rehabilitation. EEG assessment was analyzed using Matlab 2011A 7.9 signal processing tool box. The results were statistically analyzed with SPSS 17.0 version using Wilcoxon signed rank and Friedman test RESULTS: Amplitude, power of alpha waves and cognitive scores increased gradually with highest mean rank for implant supported overdenture (IOD). The bivariate analysis between two groups showed there was significant difference between all the groups (p < 0.05) except for groups CE-I (completely edentulous - implant placement) and CD- I (complete denture insertion - implant placement) in amplitude of alpha waves while in group CD-I with respect to power of alpha waves. MMSE revealed the mean of cognitive scores in Complete Edentulous was 17.40, Complete Denture was 18.30 and finally with Implant Overdenture was 23.80. CONCLUSION: The present study has enlightened the significance of two implant supported mandibular overdenture in improving the mental state of an individual and that the enhancement was due to functional improvement with prosthesis when loaded with implants and not due to mere existence of implant without any function.

Dimensional change in soft tissues with complete dental prosthesis and its effect on airway space and natural head position.

BACKGROUND: Insertion of the intraoral prosthesis causes deflection of the tongue, soft palate affecting the patency of the airway. AIMS: To evaluate the cephalometric soft tissue variation in tongue, soft palate, and its effect on posterior airway space in edentulous patients with the insertion of the denture. SETTINGS AND DESIGN: Randomized controlled trial. MATERIALS AND METHODS: Complete denture (CD) prosthesis was fabricated for first time denture wearers comprising 22 males and 18 females within the age range of 50-65 years. Lateral skull radiographs were taken for each of the subjects in their resting position without CDs (T0), with CDs (T1) at least 1-week postinsertion and after 6 months of usage (T2), respectively. The reference points, lines, and angles on the cephalometric films were used to evaluate the position or inclination of the head, variations in tongue position and length, the changes in the anteroposterior dimension of the soft palate, and posterior airway space variations. Intra-investigator error variance was not found to be statistically significant (P < 0.05). STATISTICAL ANALYSIS USED: Using Statistical Package for the Social Sciences (SPSS) v16.0 the significant difference in the paired samples (without CD and with CD) was found using the paired t-test. The probability value P = 0.05 is considered as a significant level. RESULTS: On comparison of T1 and T0, the heads were more extended with the downward position of the tongue with an increase in its length and the posterior airway space was decreased in T1. Significant differences in values were not observed between T1 and T2. CONCLUSIONS: With CDs, the change in airway space was related to alteration in soft palate and tongue dimension. There were no changes in dimension at 6 months follow-up.