Biomedical subjects

Zeev Ormianer

Publications and source records attributed to Zeev Ormianer.

9 recordsLinked to original sources

PubMed2006

Immediate loading of implant overdentures using modified loading protocol.

To our knowledge, this study shows the first longitudinal results (range 12-30 months) of immediate loading of implant-support overdenture with ball attachment connection placed in the anterior mandible. Immediately after surgery, the overdenture was connected to the implants with 2-ball attachments. The housings were filled with Impregum (3M Espe AG; Seefeld, Germany) impression material to provide retention as well as reduce forces in the initial phase of loading. Of the 28 implants placed, only 1 failed; the 1 failed implant for total implants placed represents a success rate of 96.4%. The minimal bone loss (1 mm) in 2 sites represents a success rate of 92.8%.

Aged↗

PubMed2006

Heat transfer of impression plasters to an implant-bone interface.

PURPOSE: The purpose of this in vitro study was to measure heat generated at the implant-bone interface caused by exothermic setting reaction of 2 impression plasters. MATERIALS AND METHODS: The study consisted of 20 titanium-alloy abutment impressions connected to a titanium-alloy cylindrical implant embedded in an acrylic-resin mandible in a 37 degrees C water bath. There were 2 types of impression plaster used, Snow-White (Kerr, Romulus, MI) and Xantano (Kulzer, Dormagen, Germany). Temperature changes were recorded via embedded thermocouples at the cervix and implant surface apex. Analysis of variance for repeated measures was used to compare 2 treatment groups. RESULTS: Temperature increased less at the implant apex (1.5 degrees-2.1 degrees C) than at the implant cervix (7.4 degrees-10.5 degrees C). Differences between the 2 impression plasters were statisticallysignificant only at the implant cervical level (P < 0.05). A lower temperature increase was shown with the Snow-White compared with the Xantano. Although both plasters generated an exothermic reaction on setting (mean temperature change 22 degrees C), the increase in the temperature rate of the Snow-White was slower than the Xantano. CONCLUSIONS: Under the conditions of the present study, Snow-White impression plaster appears to be safer to use in implant prosthodontics compared with the Xantano because of its slower and lower exothermic reaction at the implant-bone interface. However, use of the material with the rapid setting time would require more care, such as limiting the volume of material used (e.g., by using a custom tray).

Acrylic Resins↗

PubMed2006

Survival of immediately loaded dental implants in deficient alveolar bone sites augmented with beta-tricalcium phosphate.

PURPOSE: Dental implant placement in atrophic alveolar ridges often necessitates grafting procedures, followed by immediate or delayed implant placement. This study assessed the survival of immediately loaded dental implants placed in deficient alveolar bone sites at bone grafting. MATERIALS: From 1999 to May 2002, 1 operator (A.P.) inserted 1065 implants (607 in mandibles, 458 in maxillae) into 338 partially edentulous patients. Most implants were placed into compromised residual ridges or prepared tooth extraction sockets. Implants placed in augmented areas were splinted to implants in nonaugmented sites for stability. In all cases, beta-tricalcium phosphate was mixed with blood from the surgical site to augment the ridge level or fill spaces between the implant and socket wall. When indicated, the same materials were used for sinus floor augmentation. All implants were tapered screws with roughened surfaces, primarily (75%) from 1 manufacturer. One of the authors (Z.O.) prosthetically restored a total of 189 implants that were placed in 35 patients. In this group of patients, complete restorative data were available. All implants were monitored for 12-48 months (mean = 19.2; median = 24). RESULTS: A total of 1039 implants survived, and 26 failed, including 5 in the anterior mandible and 21 in the maxillae. In the restorative group, 186 implants survived, and 3 maxillary implants failed. All implant failures in this study occurred in the augmented sites. CONCLUSION: Within the limitations of this study, immediate loading of splinted implants in augmented sites is a predictable procedure.

Alveolar Ridge Augmentation↗

PubMed2006

Consensus conference on immediate loading: the single tooth and partial edentulous areas.

PURPOSE: A consensus conference was held to determine what the parameters should be for the immediate functional loading of the single-tooth implant restoration and short-span fixed implant-supported bridgework. MATERIALS: Forty-one clinicians and researchers presented cases and situations relating to the topic. A panel then distilled questions that were presented to the audience (430) at large. Answers were gleaned to formulate a consensus. RESULTS: Ten distinct answers evolved that constituted the essence of guidelines for clinicians to be aware of when undertaking immediate loading. These guidelines are contained within the body of the text. CONCLUSIONS: Extreme caution and adherence to a universal generic protocol are suggested for clinicians who are involved with single-tooth and short-span multiple-teeth implant replacements as related to immediate loading as defined within this text.

Dental Abutments↗

PubMed2006

Long-term clinical evaluation of tapered multi-threaded implants: results and influences of potential risk factors.

This prospective study evaluated the long-term performance of tapered screw implants placed in patients with a variety of potentially compromising clinical variables. Sixty patients were treated with 218 implants; each case included one or more potential risk factors associated with increased rates of implant failure, peri-implant bone loss or clinical complications in the dental literature: short implants (23%), comorbid conditions (25%), maxillary implants (61%), immediate loading (88.5%), placement into extraction sockets (91%), and partial edentulism (97%). The implants were restored with a variety of prostheses. Marginal bone changes were calculated utilizing periapical radiographs taken at placement and at all subsequent appointments utilizing a standardized paralleling device and a 1-mm measurement grid. Mean clinical follow-up was 67.5 (range: 1-94) months for implants and 60 (range: 15-74) months for prostheses. Four implants failed to integrate and were immediately replaced by wide-diameter implants. Eight prostheses sustained porcelain fracture (n = 7) or cement failure (n = 1) and were replaced. No peri-implant marginal bone loss was observed for 98% of the implants; the remaining 2% exhibited 1 mm of bone loss. Cumulative survival rates were 98.2% for implants and 96.3% for prostheses after 5 years of clinical loading. Concerns that tapered implant designs may be more prone to crestal bone loss than cylinder designs are unsupported by the results of this study. Tapered implants maintained integration and marginal bone levels despite the presence of one or more potentially compromising variables.

Adult↗

PubMed2006

Maxillary single-tooth replacement utilizing a novel ceramic restorative system: results to 30 months.

This study reports on the first longitudinal results of an alumina (70%)-zirconia (30%) ceramic restorative system for implant-supported, single-tooth replacement in the anterior maxillary jaw. Eighteen patients (9 men, 9 women, mean age = 42.4 years) were treated with 22 implants placed into 19 extraction sockets and 3 residual ridges. Eight implants were immediately loaded with nonoccluding provisional prostheses. All implants were definitively loaded with fully occluding ceramic restorations after osseointegration and soft tissue maturation. Patients were monitored from 7 to 30 months (mean = 18.1 months) after loading. All implants osseointegrated and were successfully restored. One case of abutment screw loosening occurred because of patient parafunction (bruxing), and another patient reported chewing pain attributed to malocclusion. Both problems were successfully resolved without further incidence. Within the context of this study, single-tooth replacement in the anterior maxillary jaw was successfully achieved with alumina-zirconia ceramic single-tooth restorations with up to 30 months of clinical function.

Adolescent↗

PubMed2005

Strains recorded in a combined tooth-implant restoration: an in vivo study.

Implant-supported fixed prosthesis is a treatment option to restore missing teeth. Occasionally, it is necessary to connect teeth and implants as abutments for these restorations. Whether such restorations can be recommended is a matter of debate. This in vivo study measured strains involved in connecting implants to a natural tooth and compared rigid and nonrigid tooth/implant connections. A patient was treated with mandibular unilateral fixed prosthesis supported by two implants and one proximal tooth. Strain gauges were cemented to the experimental framework restoration. Recordings were obtained from the restorations while the patient bit on a wooden stick on the day of placement and after 2 weeks in function, using both rigid and nonrigid attachment connections. A significant difference was found in horizontal deformation of the tooth/crown between day 1 and 2 weeks later. Vertical deformations were smaller than horizontal ones. After applying biting forces, horizontal and vertical deformations were maintained. Strain recorded in a clinical setting revealed mostly horizontal strains generated in a combined tooth/implant device. These strains were maintained after a 2-week recording. Within the limitation of this study, combined tooth/implant restorations could be a potential complication and could cause an intrusion of a natural abutment regardless of the type of connection (rigid or nonrigid).

Bite Force↗

PubMed2005

Use of dental implants to improve unfavorable removable partial denture design.

This study aimed to determine whether the use of a limited number of dental implants, with no rigid connection between implants and teeth and as few as possible prosthetic element requirements, is a viable solution for improving unfavorable removable partial dentures (RPD) design. Fifteen partially edentulous patients with an unfavorable number and distribution of abutment teeth were treated, each with a limited number of implants, from 1997 to 2004, resulting in an improved RPD design. Implant survival rate was 100%, and prosthetic complications were minor. All patients reported great satisfaction with the partial dentures and good chewing efficiency. The results indicate that the use of dental implants to improve unfavorable RPD design is a viable and cost-effective treatment modality.

Dental Abutments↗

PubMedDate not supplied

The effect of increasing occlusal vertical dimension on face height.

PURPOSE: This study evaluated the effect of increasing occlusal vertical dimension (OVD) on the face height in completely dentate young adults. MATERIALS AND METHODS: Faces of 22 subjects were photographed in a standardized manner in an anterior view. Sequential photographs were taken at intercuspation and clinical rest position, with four complete arch maxillary occlusal overlays increasing OVD in interincisal increments of 2, 4, 6, and 8 mm. Objective measurements were made from the photographs using facial reference markers. Ten observers made subjective evaluations of the resulting changes in face height using the sequential photographs randomly presented. RESULTS: Measurements of the facial markers showed that on increasing OVD, a corresponding change in lower face height was 50% of the interincisal increase in intercuspation and 40% for clinical rest position. ANOVA for repeated measures showed a statistically significant effect of the intraoral increase in OVD on lower face height. However, subjective results showed that observers were not capable of detecting changes in face height caused by an intraoral increase in OVD (2 to 6 mm intrinsically). ANOVA for the difference between dentists and nondentists showed a minimal, but significant, difference between the two groups, with dentists erring slightly less. CONCLUSION: Attempts to alter face height by changing OVD within the range of 2 to 6 mm for esthetic reasons may not be visually distinguishable.

Adult↗