Do effervescent vitamin tablets affect the surface roughness, microhardness, and color of human enamel and contemporary composite resins?

PURPOSE: To compare the impact of four effervescent vitamin tablets on the surface roughness, microhardness, and color of human enamel and contemporary composite resins. MATERIAL AND METHODS: Sixty enamel and a total of 240 anterior (Gradia Direct Anterior), posterior (Gradia Direct Posterior), and universal composite resin (Filtek Ultimate) specimens (n = 60 per group) were fabricated. Each group was subdivided into five subgroups (n = 12, per subgroup). The specimens were subsequently immersed in YOUPLUS, Redoxon, Sunlife Immuvit, and Sambucol effervescent vitamin solutions for 2 min per day over 30 days. Distilled water was used as control. Subsequently, surface roughness (Ra) was detected using a profilometer, and microhardness (VHN) was measured using a microhardness tester. A spectrophotometer device was used to record the L,a,b color coordinates of the specimens after 24 h, 7 days, and 30 days, and the color changes (ΔE00) of the groups were calculated. The data were analyzed by ANOVA, two-way ANOVA, Kruskal-Wallis, Levene's, and Fisher's least significant difference (LSD) tests (p < 0.05). SEM analysis was conducted on one randomly selected specimen per group (×1000). RESULTS: In terms of surface roughness, material X vitamin interactions were found significant (p < 0.05). The increase in Ra from 24 h to 30 days was found significant (p < 0.05) except for Gradia Direct Anterior X Redoxon, Sunlife Immuvit and Sambucol, Filtek Ultimate X Sunlife Immuvit and Sambucol, and all control groups. Ra changes were also concluded by SEM. Regarding VHNs, material X vitamin interactions were significant (p < 0.005), except for all Filtek Ultimate subgroups. The changes in VHNs of the groups from 24 h to 30 days were significant for all enamel and Gradia Direct Anterior X YOUPLUS, Gradia Posterior X YOUPLUS, Sunlife Immuvit, and Sambucol groups (p < 0.05). In terms of ΔE00, significant differences were observed between the 7 days and 30 days in the enamel (p = 0.047), Gradia Direct Anterior (p = 0.019), and Gradia Direct Posterior groups (p = 0.038). CONCLUSIONS: Daily consumption of effervescent vitamin tablets can increase surface roughness, decrease microhardness, and influence the color of human enamel and contemporary anterior, posterior, and universal composite resins after a 30-day period.

Effect of Denture Cleansing Solutions on the Retention of Locator Attachments Over Time.

PURPOSE: To evaluate and compare the alterations in retention of three Locator attachments after immersion in various denture cleansers at defined time intervals. MATERIALS AND METHODS: Two implants were embedded in an acrylic block. Pink, blue, and clear Locator attachments (n = 10 for each subgroup) were immersed into three different cleansing solutions (Corega, Protefix and NaOCl) and tap water (control) at different time intervals that simulate 1 (T1 ), 6 (T2 ), and 12 (T3 ) months of clinical use. Universal testing machine set at a crosshead speed of 50 mm/min was used for pull-out tests. After the immersion procedure, the peak force to dislodgement was recorded to demonstrate the changes in retention of Locator attachments. Data were analyzed using repeated-measures ANOVA followed by Tukey's Honestly Significant Difference (HSD) tests (α = .05). RESULTS: All denture cleansing solutions affected the retentive values of all Locator attachments at defined time intervals (F = 4.299, p = 0.001). NaOCl affected all groups significantly after 12-month immersion time (p = 0.001). The least retention loss at all subgroups was observed in Corega for clear Locator attachments (106.17 ± 5.21 N). The difference in retention values for pink attachments were not statistically significant for tap water, Protefix and Corega immersion at all time intervals (p > 0.05). Following NaOCl (blue; 33.31 ± 4.72 N, clear; 52.3 ± 8.5 N), tap water decreased the retention value of blue (41.14 ± 3.93 N) and clear (76.72 ± 8.42 N) Locator attachments at T3 . Corega caused the least retention loss to clear attachments at T1 (106.17 ± 3.55 N). CONCLUSION: The retention of Locator attachments decreases over time after exposure to various denture cleansing solutions. As NaOCl significantly decreased the retentive values of all attachments, patients must be informed about that disadvantage. Also, tap water remarkably decreased retentive ability of all attachments. Periodic addition of an effervescent tablet into tap water may be recommended to patients that wear implant retained overdentures with Locator attachments.

Biomechanical Behavior of Implants with a Sloped Marginal Configuration.

PURPOSE: To evaluate the biomechanical behavior of implants with different neck designs. MATERIALS AND METHODS: Finite element models of implants with two different neck designs (OsseoSpeed EV and OsseoSpeed Profile EV) were generated. Implants and abutments were subjected to buccally and lingually directed 30-degree oblique loads of 200 N. RESULTS: Under buccally angulated load, the Profile implant model showed lower minimum principal stress when compared to the standard implant model (-63.4 vs -91.9 MPa), whereas the von Mises stress value of the Profile implant model was higher (342 MPa). CONCLUSION: This preliminary study showed that Profile implants placed in alveolar ridges with buccolingual bone height discrepancy showed similar stress distribution and stress value outcomes when compared to standard implants.

The Fracture Resistance of Composite Core Materials Reinforced by Varying Fiber Orientations.

This study aimed to compare the fracture resistance of composite core materials reinforced with varying fiber orientations. Composite cores of endodontically treated roots were prepared by reinforcing with woven fiber discs, fiber strips, or fiber chips, and their fracture resistance was compared to those with no reinforcement using a universal test machine (Instron, Lloyd Instruments). Reinforcement with fiber chips showed the highest fracture resistance and 50% retrievability, while no reinforcement showed the lowest fracture resistance with 62.5% retrievability. It can be concluded that the use of fiber chips may be an effective and practical method for reinforcement of the core material.

Effect of engraving speeds of CO2 laser irradiation on In-Ceram Alumina roughness: a pilot study.

OBJECTIVES: The aim of the study was to determine the effect of CO2 laser on surface roughness of In-Ceram-Alumina-ceramic. MATERIALS AND METHODS: Four aluminum-oxide ceramic disc specimens were prepared of In-Ceram Alumina. Discs received CO2 laser irradiation with different engraving speeds (100, 400, 600 and 800 mm/min) as a surface treatment. The roughness of the surfaces was measured on digital elevation models reconstructed from stereoscopic images acquired by scanning-electron-microscope. Surface roughness data were analyzed with One-Way-Analysis-of-Variance at a significance level of p<0.05. RESULTS: There was no significant difference between the roughness values (p=0.82). Due to higher laser durations, partial melting signs were observed on the surfaces. Tearing, smearing and swelling occurred on melted surfaces. Swelling accompanying melting increased the surface roughness, while laser power was fixed and different laser engraving speeds were applied. CONCLUSION: Although different laser irradiation speeds did not affect the roughness of ceramic surfaces, swelling was observed which led to changes on surfaces.

Intraoral use of extraoral implants for oral rehabilitation of a pediatric patient after resection of ewing sarcoma of the mandible and reconstruction with iliac osteocutaneous free flap.

Large osseous defects secondary to resection of the mandibular segment may lead to significant facial deformity, functional disabilities, and associated psychologic problems. The therapeutic approach is more complicated in pediatric patients because it must not interfere with normal craniofacial growth process. Here, we present a clinical report to emphasize the application of extraoral short implants with magnetic abutments used for mandible of a growing patient reconstructed with free iliac flap after resection of Ewing sarcoma. A 5-year-old boy, complaining of an ulcerated mass of the anterior mandibular area and floor of the mouth, was referred to our clinic. Incisional biopsy from the lesion confirmed the diagnosis of Ewing sarcoma. After resection, free iliac osteocutaneous flap, with a 6.5 × 4.0-cm skin paddle and based on the deep circumflex iliac vessels, was used to reconstruct the mandibular integrity and to cover the floor of the mouth simultaneously. Nine months after the operation, the patient was referred for oral rehabilitation. Prosthodontic plan included the placement of 5 extraoral implants with magnetic abutment and fabrication of an implant-retained overdenture. Magnetic abutment was preferred not to interfere with the expected craniofacial growth. During a follow-up period, radiographic images showed no pathologic signs with consideration of overall bone loss and recurrence of the tumor; 12 months after the initiation of prosthetic loading, no peri-implant bone loss was observed. In conclusion, this reported case would be an example for the management of challenging pediatric mandibular tumor cases in terms of resection, reconstruction and dental rehabilitation.

Effect of preparation taper and height on strength and retention of zirconia crowns.

This study aimed to determine the effect of the taper and height of tooth preparations on the fracture strength and retention of zirconia crowns. Sixty-four dies were designed to simulate a crown preparation. Dies were machined with a height of either 4 mm (n = 16) or 7 mm (n = 16) and a taper of either 6 degrees (n = 16) or 20 degrees (n = 16). Copings were created from Lava zirconia blanks. Retention tests were performed using a universal testing machine. Copings were recemented on the dies, thermocycled, and tested for fracture strength. Data were analyzed using factorial analysis of variance. Retention was greater in the taller and less-tapered preparation designs. Taller preparations showed superior fracture strength. Preparing posterior teeth with higher axial walls and less taper is recommended to achieve increased retention and strength for zirconia crowns.

Effect of repeated firings on microtensile bond strength of In-Ceram Alumina with two different veneering ceramics.

Microtensile bond strengths of In-Ceram Alumina cores veneered with two ceramics after different numbers of firing cycles were evaluated. After In-Ceram Alumina cores were fabricated, they were veneered with either Vitadur Alpha or Vita VM7. A control group of each core-veneer combination was fired twice, and a second group was fired five times to induce thermal fatigue. Obtained microbars were subjected to microtensile bond strength tests. Data were analyzed using two-way analysis of variance. Microtensile bond strength values for Vita VM7 specimens were higher than those for Vitadur Alpha (P < .001). Although the number of firing cycles revealed no change in bond strength, the veneering material proved to be an important factor.

Periauricular mold brachytherapy.

PURPOSE: We present a patient with recurrent basal cell carcinoma (BCCA) who was treated with custom-made mold brachytherapy. METHODS AND MATERIALS: The patient was admitted to the hospital with the complaint of recurrent BCCA of the auditory canal. He has previously treated by surgery and external beam radiotherapy. We decided to continue with reirradiation to tumor bed after surgical excision. A total of 25 Gy to 5mm depth of surgical bed was delivered by mold brachytherapy. RESULTS: The patient did well during the treatment without any acute toxicity. He was lost to followup after 2 years of treatment without any obvious late morbidity. CONCLUSION: Custom-made mold brachytherapy is an alternative treatment modality, for reirradiation of selected group of patients, with minimal morbidity and good disease control.

Surface roughness and bond strengths of glass-infiltrated alumina-ceramics prepared using various surface treatments.

OBJECTIVES: To compare and evaluate effects of CO(2) laser and conventional surface treatments on surface roughness and shear bond strengths of glass-infiltrated alumina-ceramics to dentin. METHODS: One hundred fifty ceramic discs of In-Ceram Spinell, In-Ceram Alumina and In-Ceram Zirconia (n=50) were prepared. Specimens which were divided into 5 groups (n=10) were untreated (control group), sandblasted, airborne particle abraded, etched with 9.6% hydrofluoric acid or irradiated with CO(2) laser. Scanning electron microscope was used at 1000x magnification for qualitative examination. Following surface roughness (Ra) determination by profilometry, discs were cemented on extracted-human-molar teeth. Cemented specimens were stored in distilled water at 37 degrees C for 1 week. Shear bond strength (MPa) test was performed using a universal testing machine at a crosshead speed of 1mm/min. Statistical comparisons were made with Wilcoxon signed ranked test, Kruskall Wallis test and Spearman's correlation coefficient. RESULTS: All surface treatments produced rougher surfaces than the untreated groups of all ceramics (P<.05). Sandblasting demonstrated a rougher surface on In-Ceram Spinell than In-Ceram Alumina and In-Ceram Zirconia (P<.05). While CO(2) laser irradiation showed significantly higher bond strength for In-Ceram Spinell (P<.05), both airborne particle abrasion and CO(2) laser irradiation showed higher bond strengths for In-Ceram Zirconia (P<.05). Airborne particle abrasion demonstrated higher bond strength for In-Ceram Alumina and In-Ceram Zirconia (P<.05). No significant relationship was determined between surface roughness (Ra) and shear bond strength values (MPa) among ceramic groups. CONCLUSIONS: Sandblasting is an effective surface treatment for roughening surfaces of In-Ceram Spinell. Although CO(2) laser irradiation does not increase surface roughness, it reveals the highest bond strength.

An alternative post-and-core method for patients with limited interarch space.

BACKGROUND: The authors describe a technique for placement of a three-unit posterior fixed partial denture where one abutment lacked sufficient interarch space. CASE DESCRIPTION: This method involves the use of a cast post and core with a precision attachment soldered into the core to provide the necessary retention and resistance. The prosthesis is retained by a combination of cement and screw retention. CLINICAL IMPLICATIONS: This method is desirable when there is insufficient interarch space for a conventional post-and-core restoration. Achieving internal reinforcement by connecting the precision attachment to the residual root should provide the prosthesis with retention and added stability.