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Biomedical subjects

D M Vassos

Publications and source records attributed to D M Vassos.

At least 19 recordsLinked to original sources
PubMed2000

Retrospective multicenter study of an anodized, tapered, diminishing thread implant: success rate at exposure.

Performance of a new tapered, threaded implant at exposure was evaluated retrospectively using conservative assessment criteria. The criteria used were intended to ensure that an implant in the early stages of failing as well as those implants that have clearly failed would be identified as such. These results reflect an evaluation preliminary to comparing the performance of the implant at exposure and its performance (i.e., success rate) observed after longer periods (i.e., > or = 1 year) of loaded service. Data from 663 patients treated in the setting of the authors' private practice offices were evaluated to assess the performance of the implant under representative "clinical practice" usage conditions. The implant success/failure criteria were prospectively defined and applied to data obtained in a masked fashion from patients' records. Neither the dentist nor personnel involved in the analysis of the data were aware of which patients were qualified for and included into the study. Of 1100 implants available for evaluation, 15 implants failed at or before exposure. The success rate at exposure was 98.6%. There was no correlation between the anatomical region in which an implant was placed and the incidence of implant failure. Implants placed in fresh extraction sites and/or grafted sites appeared to be more likely to fail at exposure. Conversely, the failure rate of implants placed using a single-stage surgical procedure was comparable to that of implants placed using a conventional two-stage surgical methodology. Immediately loaded implants experienced a success rate comparable to that of implants placed using conventional two-stage surgical procedures. Factors under the clinician's control may play a substantial role in determining implant performance at exposure.

Adolescent↗
PubMed1997

Long-term efficacy of hydroxyapatite-coated cylindrical implants.

A two-site clinical study of hydroxyapatite-coated cylindrical titanium alloy implants was undertaken to evaluate their efficacy. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly postrestoration prophylactic examinations and annual comprehensive patient visits. Implant failure criteria included mobility, peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain on palpation. Soft tissue indices were monitored as part of the study. Postrestoration implant performance was analyzed using life table methodology. From the 316 implants restored in 154 patients, 11 implants in 8 patients failed before prosthetic attachment, for a surgical success rate of 96.4 percent. Four implants failed during an observation period extending up to 85 months after completion of prosthetic treatment. The Cutler-Ederer life table success rate after 6 years was 97.8 percent. No significant adverse events were reported during the observation period. Results of this investigation suggest that hydroxyapatite-coated cylindrical titanium alloy implants are an effective treatment modality.

Adolescent↗
PubMed1997

Single-stage surgery for implant placement: a retrospective study.

Single-stage implant placement surgery offers patients a number of advantages. These include reduced cost and time commitments and greater comfort, function, and convenience. This article reports on the results of using a single-stage technique with 58 patients fitted with 240 implants. No implant failures were detected in any patients prior to the final attachment of a Dolder bar. Among the 27 patients and the 125 implants followed for a longer period of time, 99.2% exhibited no signs of implant mobility or pain. Indicators of gingival health and oral hygiene ranged in quality from acceptable to ideal.

Adult↗
PubMed1996

Efficacy of threaded hydroxyapatite-coated implants in the anterior mandible supporting overdentures.

A data subset from an ongoing prospective multicenter clinical study of threaded hydroxyapatite-coated implants was evaluated to assess safety and efficacy of the implants when placed in the anterior mandible to support overdentures. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly postrestoration prophylactic exams and annual comprehensive patient visits. Implant failure criteria included mobility, radiographic evidence of bone loss greater than one-third the length of the implant or peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain upon palpation. Soft tissue indices were monitored as part of the study. Postrestoration implant performance was analyzed using life-table methodology. From the 2,062 implants restored in 720 patients in the parent study, a total of 660 implants in 174 patients were included in the anterior mandibular overdenture data subset. Twelve implants in 8 patients failed at or before second-stage surgery for a surgical success rate of 98.2 percent. Five implants failed during an observation period extending up to 72 months after completion of prosthodontic treatment. The Cutler-Ederer life table success rate after 5 years was 97.8 percent. No significant adverse events were reported during the observation period. Results of this investigation suggest that threaded hydroxyapatite-coated implants are effective when placed in anterior mandibular regions in support of overdentures.

Adult↗
PubMed1996

Efficacy of threaded hydroxyapatite-coated implants placed in the posterior mandible in support of fixed prostheses.

A data subset from an ongoing prospective multicenter clinical study of threaded hydroxyapatite-coated implants was evaluated to assess safety and efficacy of the implants when used to support fixed prostheses in the posterior mandible. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly postrestoration prophylactic exams and annual comprehensive patient visits. Implant failure criteria included mobility, radiographic evidence of bone loss greater than one-third the length of the implant or peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain upon palpation. Soft tissue indices were monitored as part of the study. Postrestoration implant performance was analyzed using life-table methodology. From the 2,062 implants restored in 720 patients in the parent study, a total of 423 implants in 195 patients were included in the posterior mandibular data subset. Thirteen implants failed at or before second-stage surgery for a surgical success rate of 96.9 percent. Prosthodontics was completed, and one or more postrestoration annual follow-up visits occurred for 314 implants as of the interim analysis cutoff date. Fourteen implants failed during an observation period extending up to 62 months after completion of prosthodontic treatment. One failed implant was removed, whereas the 13 remaining implants are functional despite having been identified as failures under the protocol criteria. The Cutler-Ederer life table success rate after 5 years was 92.2 percent. Results of this investigation suggest that threaded hydroxyapatite-coated implants are effective when placed in posterior mandibular regions in support of fixed prostheses.

Adult↗
PubMed1995

Efficacy of threaded hydroxyapatite-coated implants placed in the anterior mandible.

A data subset from an ongoing prospective multicenter clinical study of threaded hydroxyapatite-coated implants was evaluated to assess safety and efficacy of the implants in anterior maxillary regions when used to support fixed prostheses. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly post-restoration prophylactic exams and annual comprehensive patient visits. Of 2,062 implants restored in 720 patients in the parent study, a total of 95 implants in 54 patients met the criteria for inclusion into this portion. Implant failure criteria included mobility, radiographic evidence of bone loss greater than one-third the length of the implant or peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain upon palpation. Soft tissue indices were monitored as part of the study. Post-restoration implant performance was analyzed using life-table methodology. No failures were observed before prosthodontic rehabilitation. Three implants failed during an observation period of up to 5 years after completion of prosthodontic treatment. The Cutler-Ederer life table success rate after 5 years was 93.4 percent. Results of this investigation suggest that threaded hydroxyapatite-coated implants are safe and effective when placed in anterior maxillary regions to support fixed prostheses.

Adult↗
PubMed1995

Interim clinical study report: a threaded, hydroxylapatite-coated implant--five-year post-restoration safety and efficacy.

An ongoing prospective clinical trial is being conducted at three study sites to evaluate the safety and efficacy of a threaded, hydroxylapatite-coated implant (Steri-Oss Inc., Yorba Linda, CA) in a patient population reflective of the investigators' overall population of implant candidates. The 2062 implants placed and restored among 720 patients over the five-year period up to the study interim analysis cut-off date (November, 1994) include over 600 implants and 200 patients at each study site. Mean age and sex distribution of patients were comparable among the study sites. Study design attributes included well-defined patient selection criteria, standardized study procedures, standardized measurement and observation methodology, complete data accountability, and rigorously applied implant success/failure criteria. Thirty-five implants were considered failures at exposure, and the surgical success rate was 98.3%. Of 65 implants that failed post-restoration, three were removed, while 62 remained functional and in service. The five-year post-restoration follow-up success rate, determined by means of life table methodology, was 96.0%. By region, the five-year life table success rates post-restoration were 94.3% in the anterior maxilla, 96.6% in the posterior maxilla, 97.2% in the anterior mandible, and 95.6% in the posterior mandible. Adverse events occurred in association with less than 1% of the implants placed.

Adolescent↗
PubMed1993

A five year clinical evaluation showing optimum results in dental implants.

Implant dentistry has made great advances since its inception several decades ago. As a result, predictability and success have reached high levels. Nonetheless, efforts continue to further refine implant design, materials, and techniques to reduce even the small percentage of failures that still occur. As part of this effort, the authors for the past six years have conducted clinical trials of Steri-Oss threaded titanium implants and HA-coated implants. The results have been consistent with the body of implant research reported since the 1970s. Optimum implant performance is realized when a well-designed system such as those tested is utilized in association with astute clinical judgment.

Clinical Trials as Topic↗
PubMed1992

Dental implant treatment in a severely compromised (irradiated) patient.

When faced with a patient with relative medical or psychological contra-indications, the practitioner may be tempted to withhold dental implant treatment because of the risks. Yet, for some highly motivated but compromised patients, the potential benefits of implant treatment can be an overriding consideration. In the case presented here, a 56-year-old patient who had undergone two series of radiation therapy and surgery for recurring cancer of the tongue was treated first with a subperiosteal, and, when the subperiosteal was removed after six years, the patient was treated with endosseous implants. This treatment significantly improved the patient's life without further negative effect on her medical condition.

Contraindications↗