[Show abstract][Hide abstract] ABSTRACT: The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials.
The journal of advanced prosthodontics 06/2014; 6(3):224-32. · 0.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: STATEMENT OF PROBLEM: Clinical studies on implant-retained maxillofacial prostheses have focused on biological outcomes. An assessment of the effect of prostheses on patients' quality of life (QOL) by using specific questionnaires developed for this patient population provides important information on treatment outcomes from the patients' perspectives. PURPOSE: The purpose of this study was to report patient-based outcomes of implant-retained maxillofacial prostheses and to evaluate the effect of implant-retained maxillofacial prostheses on QOL of participants in a prospective study. MATERIAL AND METHODS: Eighty-two participants were treated with implant-retained maxillofacial prostheses. Participants were divided into 2 groups: a retrospective group (participants treated and under care) and a prospective group (participants willing to be treated). The posttreatment patient satisfaction scores for each question were statistically analyzed by 2-way ANOVA with variables of defect type and retention type. The Student-Newman-Keuls test was used to determine any significant differences among the groups. In the prospective group, mean scores before and after prosthetic treatment were compared with the paired t test (α=.05). RESULTS: The details of 54 retrospective and 28 prospective participants were reviewed. The posttreatment results of 82 patients showed that patient satisfaction with implant-retained maxillofacial prostheses was significantly different for cleaning the prostheses and recommending treatment to other people, depending on the defect and retention type. In the prospective group, participants reported significant increases in satisfaction for all questions. CONCLUSIONS: Implant-retained prostheses were considered highly satisfactory, indicating good QOL for patients with maxillofacial defects. A comparison of pretreatment and posttreatment assessments revealed that implant-retained maxillofacial prostheses increased patient QOL.
The Journal of prosthetic dentistry 01/2013; 109(1):44-52. · 1.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: The aim of the present study was to evaluate the effect of splinting titanium (Ti) or zirconia (Zr) implants supporting maxillary anterior fixed prostheses on the stress levels and patterns in the implants, prostheses, and the surrounding bone; and to compare the effects of Zr and Ti implant materials on the stress distribution in splinted and nonsplinted designs via finite element modeling. Materials and Methods: Zr and Ti dental implants and the anterior maxilla were modeled. In the nonsplinted design (D1), implants were placed into the maxillary left central incisor and canine regions, and a three-unit zirconia fixed prosthesis was modeled. In the splinted design (D2), a symmetric model of D1 was generated and the two prostheses were splinted together to creat a six-unit prosthesis. Loading was applied horizontally and obliquely. Von Mises, tensile, and compressive stresses were evaluated in the implants, prostheses, and surrounding bone. Results: Under both loading conditions, the stresses on the D2 implants were lower than those in the D1 implants. Stresses were concentrated on the neck of the implant and decreased through the apex. All of the stress values in cortical bone in D1 were slightly higher than in D2 for both implant materials under both loading conditions. Conclusion: When the implants were splinted together, stresses were reduced in the supporting bone and implants in both loading conditions, but increased stress was observed in the prostheses under oblique loading. Intense stress concentrations were found in the connector of the splinted prosthesis and the cervical region of the nonsplinted prosthesis. Zr and Ti implants showed very similar stress distributions in all materials. Under oblique loading, lower stresses occurred in implants and the prosthesis core material when Ti implants were used.
The International journal of oral & maxillofacial implants 01/2013; 28(1):e27-38. · 1.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This article describes a time-saving technique for fabricating a new implant-retained orbital prosthesis using the patient's existing prosthesis. The location of the ocular component is transferred; the position and openings of the palpebral anatomic structures and the precise anatomic details of the existing orbital prosthesis are duplicated. Making the impression, fabricating the definitive cast, alignment of the ocular component, and completing the wax sculpture of the prosthesis are accomplished in one appointment.
Journal of Prosthodontics 10/2011; 20(7):583-6. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effect of fatigue on biaxial flexural strength of bilayered disks of two Y-TZP cores.
Twenty bilayered veneer/zirconia disks were fabricated from each material (Lava veneer+core, 3M/ESPE, and Cercon veneer+core, Densply). Ten specimens from each material were tested for biaxial flexural strength either with or without being subjected to fatigue (20,000 cycles, 2 Hz, 200 N load) in a universal testing machine (1mm/min). Stresses generated at the core and the veneer, at the top and the bottom surfaces, and the interface of bilayered disk were calculated using Huesh's solutions. Data were statistically analyzed using Weibull statistics. The fractured core was also examined via Raman spectroscopy and the monoclinic fraction was calculated at the top, the middle of thickness, and the bottom of the cross-section of fractured core. The results of monoclinic fraction were statistically analyzed by Three-Factor ANOVA with Repeated Measures on One Factor.
Weibull modulus (m) of Cercon control (CC), Cercon fatigue (CF), Lava control (LC) and Lava fatigue (LF) were between 11.8 and 14.3, 7.1 and 13.1, 9.4 and 13, and 7.1 and 8.2, respectively. There were no significant differences between characteristic strength (σ(0)) of CC (970.9 MPa) and CF (947.7 MPa) (p>0.05). For Lava, σ(0) of LF (1444.8 MPa) was significantly higher than LC (1240.5 MPa) (p<0.05). At the interfaces, σ(0) values of CC and CF groups were not significantly different while LF showed significantly higher σ(0) than LC. The monoclinic zirconia was significantly lower for CF than CC and significantly higher for LF than LC.
Fatigue showed different effects on the strength of Cercon and Lava ceramic systems. Decreases in m values were observed at the interfaces of two materials after fatigue.
Dental materials: official publication of the Academy of Dental Materials 04/2011; 27(8):786-95. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to compare the cytotoxic effects of expired and non-expired resin-based composite materials at two, five and seven days on L929 cells. Disc-shaped test samples of expired and non-expired composite materials were prepared according to manufacturers' instructions. The samples were transferred into a culture medium for 24 hours. Eluates were obtained and pipetted onto L-929 mouse fibroblast cultures and incubated for evaluation after two, five and seven days. After each of the incubation periods, measurements were performed by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control. Statistical significance was determined by two-way analysis of variance, followed by Duncan's test. Among all composite materials, expired composites presented lower cell viability than the non-expired composites over the three-day time period; the difference in survival rates between the expired and non-expired groups was statistically significant (P < 0.05). Non-expired Quadrant Universal LC demonstrated high survival rates, followed by Filtek Z250 and Alpha-dent at two and five days. It can be concluded that expiration dates have a significant effect on the cytotoxicity of the composite materials.
The New York state dental journal 04/2011; 77(3):31-5.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to compare the von Mises (vM), compressive, and tensile stresses occurring on implants, abutments, and surrounding bone using three-dimensional finite element analysis (FEA) in three simulations in the anterior maxilla: a single titanium implant with a titanium abutment, a single titanium implant with a zirconia abutment, and a single one-piece zirconia implant.
Three types of implants (all were 4 x 12 mm) were modeled using FEA: Astra OsseoSpeed implant with titanium abutment (ATt), Astra OsseoSpeed with zirconia abutment (ATz), and White-SKY (WS) one-piece zirconia dental implant. The anterior maxillary bone was also simulated with FEA. The implants were placed into the maxillary left central incisor region. Loading was applied horizontally and obliquely and the stresses were examined.
The vM and compressive stresses that occurred on the implant and cortical bone in the ATz model were lower than those seen in the ATt model. The tensile stress values observed in the abutment and cortical bone in the ATz and ATt models and all the stress values occurring in trabecular bone were similar. The stresses that occurred in the WS implant were lower than the stresses exerted on the ATt and ATz implants, except for tensile stresses under oblique loading.
Lower stresses occurred on the zirconia implant (WS), except for tensile stress under oblique loading. The zirconia implant generated the lowest stresses in cortical bone, and the zirconia abutment resulted in lower vM and compressive stresses than the titanium abutment in implant and cortical bone.
The International journal of oral & maxillofacial implants 01/2011; 26(5):961-9. · 1.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Premature tooth loss in children may consist of single or multiple, primary or permanent, and anterior or posterior units of the dentition. This tooth loss may be due to either trauma or caries and, in some cases, to congenital or genetic defects. With anterior tooth loss cases, there are several problems the dental practitioner must consider. These are space maintenance, masticatory function, speech and esthetic appearance.
The New York state dental journal 11/2010; 76(6):27-30.
[Show abstract][Hide abstract] ABSTRACT: Objective: The aim of the present investigation was to assess thermal compatibility of different Y-TZP core material and veneering ceramics designed for zirconia by measuring the thermal expansion coefficients (TEC). Materials and methods: The materials selected for this study are 5 Y-TZP zirconia core material and 7 veneering ceramics. Cercon base (CC), Lava All-Ceramic (LC), Zirkonzahn (ZC), Vita In-Ceram 2000 YZ Cubes (VC) and Procera Bridge Zirconia (PC) were core materials. Veneering porcelains used in the study were Lava Ceram Veneer (LV), Cerabien ZR (CrbV), IPS e.max (IPSV), Vintage ZR (VnV), Vita VM9 (VtV), Zirox (ZV), and Cercon Ceram Kiss (CrcV). Three disk shaped specimens (9 mm in diameter and 4 mm in thickness) for each material were prepared. The specimens were heated from room temperature to 500 oC at a heating rate of 5 oC/ min using a thermal dilatometer. Mean values of three specimens were calculated for the TEC. Results: Coefficients of thermal expansion during heating from 25 oC to 500 oC varied with the ceramics tested ranged from 10.3 x 10-6/ oC to 11.1 x 10-6/ oC for the Y-TZP core materials and 8.6 x 10-6/ oC to 10.2 x 10-6/ oC for veneering ceramics. Conclusions: The findings of present study indicate that LV, CrcV, and IPSV showed low TEC differences with all core materials. As ZV and VntV showed acceptable compatibility with all core materials, other veneering ceramics revealed high TEC differences with some of the core materials.
[Show abstract][Hide abstract] ABSTRACT: Implant-retained extraoral prostheses are an acceptable solution for patients with facial defects. However, these prostheses have a limited service life. Little has been reported on survival periods of implant-retained extraoral prostheses and prosthetic complications of this treatment modality.
The purpose of this study was to estimate the survival rates of implant-retained extraoral prostheses and to analyze the frequency of prosthetic complications.
Seventy patients were treated with implant-retained extraoral prostheses. Each patient was examined with respect to the prosthesis appearance and abutment and attachment component complications at 6-month intervals over a period of 10 to 46 months. The Kaplan-Meier survival estimation method was used for the first and subsequent prostheses. The reasons for remaking prostheses were recorded. Complications of the abutment and attachment components and the prostheses were recorded. Frequency of complications was evaluated. Data were analyzed using the Fisher exact test (alpha=.05).
Thirty-two auricular, 25 orbital, and 13 nasal prostheses were evaluated. The Kaplan-Meier analysis revealed an estimated mean survival time of 14.5 months for the patients' first prostheses. The survival times for the first implant-retained auricular, orbital, and nasal prostheses were 14.1, 13.4, and 17.6 months, respectively. The survival times for the second implant-retained auricular, orbital, and nasal prostheses were 14.4, 15.3, and 14.0 months, respectively.
Implant-retained extraoral prostheses had limited survival rates. The primary reasons for making new prostheses were discoloration, tearing, and mechanical failures of the acrylic resin substructure or retentive elements. Common complications were the need for clip activation, loosening of bar screws and abutments, and loss of attachment between silicone and the acrylic resin substructure. (J Prosthet Dent 2010;103:118-126).
The Journal of prosthetic dentistry 02/2010; 103(2):118-26. · 1.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Radiation-induced sarcoma represents an exceptional rarity in the head and neck region. The treatment is surgical excision with negative margins and follow-up. After surgery, reconstruction of the defects can be accomplished either surgically or prosthetically. Implant-retained maxillofacial prostheses may offer an acceptable solution. In this report, a large facial defect resulting from radiation-induced leiomyosarcoma was reconstructed with implant-retained prosthesis. A patient with a large facial defect resulting from tumor surgery presented for reconstructive treatment. The primary tumor was fibrous histiosarcoma. Four years after the patient was treated with surgical resection and subsequent irradiation, leiomyosarcoma was diagnosed in the defect site. Leiomyosarcoma was treated with complete surgical resection, and the defect was reconstructed with implant-retained prosthesis. The patient was evaluated every 6 months. Implants provided secure retention to the prosthesis. The patient was satisfied with the appearance of the prosthesis. At 12 months' examination, functioning implants were successful; however, color fade of the prosthesis was observed. Radiation-induced leiomyosarcoma, which is an uncommon tumor in the head and neck region, was treated by means of large surgical resection. Implant-retained prosthetic rehabilitation of the patient resulted in acceptable functional and cosmetic results, and the patient has resumed social activities.
The Journal of craniofacial surgery 01/2010; 21(1):262-6. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the von Mises, compressive, and tensile stresses occurring on three different zirconia dental implants and surrounding bone with three-dimensional finite element analysis. Materials and
Three different zirconia implants (Z-Systems, Ziterion, and White-Sky), 10 mm in length and 4 mm in diameter, and anterior maxillary bone were modeled using three-dimensional finite element analyses. Zirconia implants were placed into the maxillary left central incisor region. Loading was applied in horizontal and oblique axes (at angles of 90 and 30 degrees with respect to the implant long axes). Oblique loading was 178 N and horizontal loading was 25.5 N.
Under oblique loading, von Mises stresses for all implants were similar, and under horizontal loading conditions, the highest von Mises stress was found at the buccal and palatal neck region of the Ziterion implant (46.57 MPa). In cortical bone, the highest von Mises stresses were observed at the buccal region of the Z-Systems implant under oblique and horizontal loading conditions (26.65 MPa and 10.74 MPa, respectively). The highest compressive stresses were observed at the implant buccal neck region and cortical bone interface of the Z-Systems implant under oblique and horizontal loading conditions. For both loading conditions, the highest tensile stress values were observed at the implant palatal region and cortical bone interface of the Z-Systems implant.
The von Mises, compressive, and tensile stresses that occurred in cortical bone were higher than those observed in trabecular bone. Generally, the stresses in the Z-Systems implant were higher than in the other zirconia implants. The differences between the stress values occurring on the zirconia implants may be related to the different body and thread designs of these implants.
The International journal of oral & maxillofacial implants 01/2010; 25(1):95-103. · 1.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this histopathologic study was to assess and compare the subcutaneous connective tissue reaction to three different maxillofacial silicone elastomers (Cosmesil, Multisil, Episil). The test materials were directly inserted subcutaneously into the dorsal subcutaneous tissue of Wistar albino rats. Histopathological examinations were done at 7, 30, and 90 days after the implantation procedure. The presence of inflammation, presence of inflammatory giant cells, and the thickness of fibrous connective tissue adjacent to each inserted sample were recorded. Data was evaluated by analysis of variance, Wilcoxon signed ranks test and Kruskal Wallis test. Cosmesil, Multisil and Episil silicone elastomers at 7 days elicited a severe inflammatory reaction. However, these reactions decreased by the 30 and 90 days. All silicone elastomers elicited a moderate inflammatory reaction at 30 and 90 days. There were no significant differences in tissue reaction between the materials at 7, 30, and 90 days (P > 0.05). All the maxillofacial silicone elastomers evaluated can not be assigned a favorable biocompatibility level based on this study's histologic findings.
Journal of Materials Science Materials in Medicine 04/2009; 20(9):1901-7. · 2.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The use of implants with extraoral prostheses provides excellent support, stability, and retention, thereby offering the potential for improving a patient's appearance and quality of life. However, few studies have examined cumulative survival rates of extraoral implants, nor have these reports documented long-term aspects of treatment, such as soft tissue health around abutments.
The purpose of this study was to evaluate the survival rates and the periimplant soft tissue responses of extraoral implants used to retain facial prostheses.
Thirty-three patients with auricular, nasal, and orbital anatomical compromise were treated with 98 craniofacial and dental implants. Of the 33 patients, 14 had auricular, 9 had nasal, and 10 had orbital defects. After a 3-month osseointegration period, implant-retained prostheses were fabricated. Following completion of treatment, each patient was seen at 6-month intervals. These examinations were recorded for this patient cohort from 25 to 50 months. Data were analyzed using Kaplan-Meier survival analysis. A 5-point scale was used to record the health of periimplant soft tissues. The unit of measure as a visit/site unit was assigned for each instance and implant site. Periimplant soft tissue reactions were assessed for auricular, nasal, and orbital defects, for each implant site used for these patients' treatments.
The overall cumulative survival rates were 100% for auricular, 83.3% for nasal, and 77.4% for orbital implants, respectively. The survival rates of the implants were 72.7% for those placed in irradiated sites treated without adjunctive HBO therapy, and 93.4% for implants placed in nonirradiated sites. To evaluate the response of the periimplant soft tissues to the implants, a total of 524 visits/sites were recorded. Absence of inflammation (grade 0) of the periabutment soft tissues was observed in 73.3% of the visits/sites.
The anatomical site into which the implant is placed has an effect on success rate. The auricular site is the most predictable implant site. Survival rates of nasal and orbital implants were found to offer promising results in achieving reliable implant prognoses in these regions. Regardless of the implant site, a decreased survival rate was observed in the irradiated sites. Periimplant soft tissue reactions were most commonly associated with lapses in hygiene.
The Journal of prosthetic dentistry 01/2009; 100(6):458-64. · 1.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this in vitro study was to evaluate the cytotoxicity of three maxillofacial silicone elastomers at 24, 48, and 72 h on L-929 cells and to determine the effect of accelerated aging on the cytotoxicity of these silicone elastomers. Disc-shaped test samples of maxillofacial silicone elastomers (Cosmesil, Episil, Multisil) were fabricated according to manufacturers' instructions under aseptic conditions. Samples were then divided into three groups: (1) not aged; (2) aged for 150 h with an accelerated weathering tester; and (3) aged for 300 h. Then the samples were placed in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12) for 24, 48, and 72 h. After the incubation periods, cytotoxicity of the extracts to cultured fibroblasts (L-929) was measured by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control (culture without sample). Statistical significance was determined by repeated measurement ANOVA (p < 0.01) followed by Duncan's test (p < 0.05). All test materials in each group demonstrated high survival rates in MTT assay (Episil; 93.84%, Multisil; 88.30%, Cosmesil; 87.50%, respectively); however, in all groups, Episil material demonstrated significantly higher cell survival rate after each of the experimental incubation periods (p < 0.05). Accelerated aging for 150 and 300 h had no significant effect on the biocompatibility of maxillofacial silicone elastomers tested (p > 0.05).
Journal of Biomedical Materials Research Part B Applied Biomaterials 08/2008; 89(1):122-6. · 2.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to compare the adhesion of oral microorganisms to different types of soft liner and acrylic resin surfaces. Three different soft lining materials were applied to cavities formed on the fitting surfaces of prostheses in 17 patients. On days 1, 7 and 14, the specimens were taken out and immediately processed for bacteriological evaluation. The numbers of adhering microorganisms were calculated and the specimens were compared among each other and also with a control group (acrylic resin). Data were analyzed by two-way ANOVA and least squares differences at a significance level of P < 0.05. Among the four materials tested the total number of oral microorganisms adhering to Softliner material was the greatest after each of the time periods tested. Higher numbers of oral bacteria and Candida were shown to adhere to soft lining materials than to acrylic resin. Microbial coverage increased continuously with time and the differences between days 1 and 14 were statistically significant (P < 0.05). Temporary soft lining materials are not resistant to adhesion and possible surface damage caused by oral bacteria, and therefore their use should be limited to short-term periods.
[Show abstract][Hide abstract] ABSTRACT: This clinical report describes the oral rehabilitation of a 6-year-old male ectodermal dysplasia (ED) patient diagnosed with hypodontia.
ED is a hereditary disease characterized by a congenital dysplasia of one or more ectodermal structures and their accessory appendages. Common manifestations include defective hair follicles and eyebrows, frontal bossing with prominent supraorbital ridges, nasal bridge depression, and protuberant lips. Intraorally, most common findings are anadontia or hypodontia, conical teeth, and generalize spaces. The patient may suffer from dry skin, hyperthermia, and unexplained high fever as a result of deficiency of sweat glands.
A six-year-old boy who exhibited many of the manifestations of ED as well as behavioral problems and a severe gag reflex. The treatment was designed to improve his appearance and oral functions and included the fabrication of several removable prostheses and acid-etched composite resin restorations during his growth and development.
Young patients with ED need to be evaluated early by a dental professional to determine the oral ramifications of the condition. When indicated, appropriate care needs to be rendered throughout the child's growth cycle to maintain oral functions as well as to address the esthetic needs of the patient. This clinical report demonstrates that removable partial dentures associated with direct composite restorations can be a reversible and inexpensive method of treatment for young ED patients.
The journal of contemporary dental practice 02/2008; 9(3):128-34.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the antibacterial and antifungal properties of polyether impression materials using the agar diffusion test. Three different types of polyether impression materials (P2, Penta Soft and Penta) were tested to determine their ability to inhibit the growth of Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The areas of inhibition zones were measured visually with a 0.1-mm incremental Boley gauge. In all groups, none of the samples of the P2 polyether impression material exhibited antibacterial or antifungal activity against any of the microorganisms. All Penta Soft and Penta samples exhibited antibacterial activity against E. faecalis and S. aureus, and only Penta samples exhibited antifungal effect against C. albicans, which decreased progressively as the setting time of the material increased.
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to evaluate the effectiveness of different disinfectants on the reduction of two resistant bacteria from the surface of impression materials. Impressions were made of a sterile metal model of the edentulous maxillary arch which had been contaminated with Staphylococcus aureus and Enterecoccus faecalis. The impressions were cultured before and after disinfection with 0.525% sodium hypochlorite, Gludex and Mikrozid spray disinfectant. For each of the three impression materials and the two microorganisms, spray disinfectant was found to be less effective than either sodium hypochlorite or Gludex.
The European journal of prosthodontics and restorative dentistry 01/2008; 15(4):177-82.