The Journal of Indian Prosthodontic Society最新文献

Aim: The main aim of the present study was to compare and evaluate the effect of repetitive firings on different shades of a pressable all ceramic system layered with veneering porcelain.

Setting and design: In-vitro comparative study.

Materials and methods: An in vitro comparative study was conducted, and a total of 60 disc shaped specimens (15 mm in diameter and 0.8 mm in thickness) were made of heat pressed ceramic of shades A2, A3, and B2 (20 discs of each shade) grouped as Group I, II, and III, respectively, using the lost wax technique. The discs were subsequently layered with veneering porcelain followed by glazing and overglazing and underwent a firing cycle at each step until six times combined. CIE L*a*b* measurements were noted on each sample after the third, fourth, fifth, and sixth firing using VITA Easyshade Advance 4.0 spectrophotometer.

Statistical analysis used: Statistical Analysis was done by SPSS 17.0 software. One way analysis of variance, multiple comparisons using the Tukey test, and descriptive statistical analysis were done for all the groups in the study. P <0.05 was statistically significant.

Results: The mean color differences for the repeated firings were imperceptible (ΔE <1.67) to the human eye for all ceramic samples tested except between the fourth and fifth firing of Group II (shade A3).

Conclusion: The analysis revealed that although repeated firings lead to changes in L*, a*, and b* values, the mean color difference was below the clinically acceptable color change (ΔE <3.7).

Aim: Implant therapy in partially edentulous patients has become the most adapted and predictable treatment modality. The success rate of implants has been measured in terms of esthetic, biological, and technical factors such as radiographic bone loss, prosthetic complications, and stability. Despite the existence of several indices for the esthetic assessment of implant crowns, a need for functional evaluation of the implant crown with an objective and reproducible score has arisen. The study aims to validate the reproducibility of the functional implant prosthodontic score (FIPS) and the influence exerted by different dental specialties while evaluating posterior single-unit implant crowns.

Study setting and design: This was a prospective clinical study.

Materials and methods: Fifteen patients with cement-retained single-implant crowns in the posterior region of the jaws were included. Eight examiners, two prosthodontists, two periodontists, two oral surgeons, and two orthodontists evaluated 15 photographs of single-unit implant crowns during the 1-year follow-up examination. The examiners assessed the photographs for FIPS, which includes five parameters for objectively evaluating the single-unit implant crowns. Assessments were performed twice at a gap of 4 weeks.

Statistical analysis used: Pearson's correlation with a 95% confidence interval was calculated for the intra-examiner and the Kruskal-Wallis test for inter-examiner reproducibility.

Results: The mean total FIPS scores for all included examiners were 7.133 for time T1 and 7.074 for time T2, showing a strong Pearson correlation coefficient for intra-examiner reproducibility. No significant difference was analyzed among different specialties with statistically significant values of the Kruskal-Wallis test.

Conclusion: Intra- and inter-examiner analysis showed very consistent results during the reproducibility assessment of FIPS. The results validated the use of FIPS as a long-term predictive functional evaluation tool for the single-implant crowns in posterior sites irrespective of the effect of different dental specialties. It could be used for risk estimation and prognosis for long-term survival and performance of implant crowns.

Background: In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application.

Aim: The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill.

Materials and methods: A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated.

Results: The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05).

Conclusion: The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

Aim: To evaluate and compare the effect of impregnated retraction cord vs Laser on gingival attachment level and pain perception following retraction for subgingival margins.

Settings and design: Many methods for achieving and measuring the amount of gingival retraction in fixed prosthodontic work have been advocated. Though the gingival attachment level is crucial in Periodontology, the literature available regarding the effect of these retraction methods on the same is scarce. Hence, this clinical study was designed to compare the pain perception and amount of gingival recession when impregnated cord and laser were used for retraction.

Materials and methods: In 40 subjects (age range of 20 to 40 years) with single missing maxillary incisor, the abutments were prepared with subgingival margins, to receive a full coverage metal-ceramic fixed dental prosthesis. The gingiva was retracted on one of the abutments with impregnated retraction cord and on the other with diode laser. Gingival attachment levels were compared at six sites per abutment using superimposition of digital scans, preoperative and four weeks after cementation of final prosthesis.

Statistical analysis used: Statistical analysis of the data for gingival recession was done using t-test. Pain perception was analysed with Chi-square test. Pain perception by patients following retraction was compared with VAS scale.

Results: The average values of gingival recession on buccal side were 0.61 mm and 0.38 mm and on the palatal side were 0.58 mm and 0.35 mm for impregnated retraction cord and laser respectively. The P values of <0.01 indicated a highly significant difference between the two groups. Intragroup comparison did not show significant differences between various sites. Pain and discomfort produced by cord method was moderate in comparison with mild/no pain with diode laser and the difference was highly significant.Conclusion: Retraction cord produced more gingival recession than the diode laser, which was statistically highly significant on both buccal and palatal aspects of the teeth. Patients experience with diode laser technique was less painful in comparison with retraction cord method.

Aim: This research aimed to assess and compare the translucency and mechanical properties of partially stabilized zirconia in contrast to lithium disilicate, particularly within the context of translucent zirconia.

Settings and design: The experimental design entails examining fifty samples, with ten drawn from each of the five distinct categories of ceramic materials, as part of this in vitro study. Translucency is measured using the Konica Minolta CM-3600D spectrophotometer, assessing Delta E through Lab values against white and black backgrounds. Flexural strength is analyzed via a 3-point bend test on a universal testing machine, with a controlled crosshead speed set at 1 mm/min.

Materials and methods: The study included the five categories of ceramic materials, each consisting of ten samples: High-strength zirconia (Katana HT), translucent zirconia (e.max Zircad MT and Cercon ht ML), and lithium disilicate (Press MT and LT). The Konica Minolta CM-3600D spectrophotometer is utilized to measure the translucency parameter. This involves determining the color difference (Delta E) by comparing the L*a*b values against both white and black backgrounds. The flexural strength (FS) of zirconia and lithium disilicate materials was analyzed through a 3-point bend test, aiming to compare their respective strengths. The testing procedure was carried out on a universal testing machine with a controlled crosshead speed set at 1 mm/min. The FS was calculated using the formula σ = FL/πR3 for circular disks, where σ represents the FS, F is the fracture load, L is the span length in millimeters, and R is the radius of the disk.

Statistical analysis used: The Student's t-test was employed for statistical analysis.

Results: The mean translucency parameter for e.max Press MT (6.33 ± 1.05) was significantly greater than all the specimens investigated. The Cercon ht ML exhibited a slightly higher translucency (2.18 ± 0.52) compared to e.max Zircad MT (1.49 ± 0.69), with a statistically significant difference (P = 0.022). Conversely, the FS of e.max Zircad MT (26.97 ± 2.06) was significantly greater (P < 0.001) than that of Cercon ht ML (23.25 ± 2.36). Notably, the Katana HT material demonstrated the highest load strength (32.92 ± 3.10), a statistically significant difference compared to its counterparts (P < 0.001).

Conclusions: Among the materials tested, lithium disilicate ceramics exhibited the highest translucency, with its MT variant demonstrating the lowest strength. Katana HT displayed significantly greater biaxial FS compared to translucent zirconia, surpassing even lithium disilicate. Translucent zirconia proved to be notably more translucent than high-strength zirconia. Within the category of translucent zirconia, e.max Zircad MT exhibited substantially higher FS than Cercon.

Aim: The aim of this within-subject prospective clinical study was to investigate the scope of single implant mandibular overdenture by assessing its masticatory efficiency, clinical performance, and patient satisfaction compared to conventional complete dentures.

Settings and design: Prospective In Vivo Study.

Material and methods: This prospective in vivo study was conducted in the Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana. A total of 12 completely edentulous patients received a single implant in the mandibular anterior midline region. After the healing period, the conventional maxillary and mandibular dentures were fabricated. 15 days post insertion of the conventional dentures, patients were evaluated for masticatory efficiency, clinical performance including retention and stability, and patient satisfaction. To evaluate the masticatory efficiency blue raspberry and original pink "Hubba Bubba tape gum" were used as a test food. Colorimetric analysis was done to assess variance of hue. To assess clinical performance, retention, and stability of the mandibular denture was recorded using a digital force gauge and was tabulated as per CU-modified Kapur's criteria. OHIP-14 index was used to assess patient satisfaction. After evaluation of the parameters of conventional dentures, the denture was converted into an implant-retained mandibular denture by chairside conversion with locator attachments. 15 days post-implant loading, parameters of the implant retained mandibular overdenture were assessed again followed by statistical analysis.

Statistical analysis used: The masticatory efficiency was assessed using a paired t-test. The patient satisfaction was sequentially assessed with Wilcoxon signed rank test and thereafter paired t-test was used to compare between conventional complete denture and overdenture. Clinical performance was assessed using the Wilcoxon signed rank test.

Results: The masticatory efficiency of single implant mandibular overdenture was higher than that of conventional complete dentures. The clinical performance of the overdenture was higher than that of the conventional denture. Stability being a time-dependent parameter might need longer follow-ups for further conclusions. Patient satisfaction with single implant retained overdenture was significantly higher than conventional complete dentures.

Conclusion: Single implant mandibular overdenture has improved masticatory efficiency, clinical performance, and patient satisfaction compared to conventional complete dentures.

Aim: The primary objective of this research was to assess and compare the impact of customized zirconia (Zr) and titanium (Ti) abutments, placed on early loaded dental implants, on both hard tissue (as measured crestal bone level) and soft tissue (as assessed by sulcular bleeding index [SBI], probing depth [PD], and Pink Esthetic Score [PES]), through clinical and radiographic evaluation.

Settings and design: This research involved a sample of 15 patients who had partially dentulous mandibular arch. Within this group, a total of 30 implants were surgically placed. Specifically, each patient received two implants in the posterior region of the mandible, and the bone density in this area was classified as D2 type. In each patient, one implant was loaded with Zr abutment and the other was loaded with Ti abutment. The bone quality in the area of implant placement was Type D2. Two groups were created for this research. Each group consisted of 15 early loaded dental implants with customized Zr abutments and customized Ti abutments respectively.

Materials and methods: Hard- and soft-tissue changes were evaluated in both the groups. Evaluation of crestal bone loss (CBL) with cone beam computed tomography and SBI, PD and PESs were evaluated by various indices at 2, 4, and 6 months postloading.

Statistical analysis used: After obtaining the readings, data were subjected to statistical analysis and comparison of quantitative data was done, paired t-test was used.

Results: The mean CBL in the Ti abutment is higher; the difference between the two groups was not statistically significant. SBI and PD for Zr were higher, but there was no statistically significant difference between the two groups. Zr had a higher PES than Ti abutment and the difference between the two groups was statistically significant. In the literature till date, the PES of Zr abutments were proven better for provisional restorations in implant prosthesis, but very few literatures support the same for the final implant restorations.

Conclusion: The study did not reveal a clear advantage of either Ti or Zr abutments over the other. Nevertheless, Zr abutments tended to produce a more favorable color response in the peri-implant mucosa and led to superior esthetic outcomes as measured by the PES.

Aim: The aim of this study was to analyze and compare the stress distribution on dental implants in various positions when used with implant-assisted removable partial dentures.

Settings and design: This was an in vitro study.

Materials and methods: A model representing a mandibular bilateral partially edentulous condition, with missing premolars and molars, was fabricated using epoxy resin. Two implants of similar diameter measuring 4.0 mm × 10 mm (Dentium, Korea) were inserted in the second molar and the second premolar region on either side of the model for comparing the biomechanical effect of various implant locations. Two types of loads 100N and 125N were applied vertically using universal testing machines in the premolar and molar regions. The loads on the implants beneath the cast partial denture were measured by physical stress analysis using a microstrain gauge.

Statistical analysis used: A comparison of maximum stress observed at the premolar versus molar regions due to the application of the 100N and 125N loads was done using the Mann-Whitney U-test.

Results: In physical stress analysis, obtained results were statistically analyzed, and the result was statistically not significant (P = 0.435 at 100N and P = 0.718 at 125N) in positional changes of implant.

Conclusion: In the current study, the statistical analysis of physical stress revealed no significant differences in stress values between the loadings at the premolar and molar regions. This suggests that the implant can be placed in either the premolar or molar region based on the availability of bone without affecting stress distribution.

Aim: Complete dentures (CDs) are fabricated to rehabilitate the edentulous. Severe residual ridge resorption (RRR) compromises CD functionality, adversely affecting function, appearance, systemic health, and quality of life.

Settings and design: The purpose of this study was to assess the benefit, if any, of calcium and Vitamin D supplementation on the rate of RRR. Retarding RRR would improve treatment prognosis and make CD fabrication less demanding.

Materials and methods: This longitudinal, parallel, open-label randomized study was conducted in the Department of Prosthodontics of the institute. One hundred and fifty edentulous subjects underwent bone mineral density (BMD) assessment followed by CD fabrication to measure RR height and width with computerized tomographic (CT) scans. Subjects were randomized to oral supplementation group - S, given combined Vitamin D and calcium daily, and nonsupplementation group - NS. Subjects from both the groups were followed up with repeat BMD test and CT scan after 12 months. Mean BMD, RR height and width, and RRR values were collected, analyzed, and compared for the two groups using STATA 17.

Statistical analysis used and results: Baseline mean T-score, RR height, and RR width were - 1.84, 22.30 mm, and 4.25 mm, respectively, for the sample. In both Groups S and NS, a statistically significant decrease in mandibular RR height (P = 0.000 for both) and width (P = 0.027 and 0.003, respectively) was observed at 1-year follow-up. There was a statistically insignificant difference between Groups S and NS for mean BMD, T-score, RR height and width, and RRR at both baseline and 12-month follow-up. One-year RRR rate for Group S (1.30 mm) was insignificantly lesser than for group NS (1.33 mm).

Conclusion: Short-term oral calcium and Vitamin D supplementation was ineffective in reducing RRR and improving BMD.