Vicki C. Petropoulos

Current concepts and techniques in complete denture final impression procedures

PURPOSE In 2001, a survey of U.S. dental schools was conducted to determine which concepts, techniques and materials are currently prevalent in the teaching of final impression procedures for complete dentures in the predoctoral clinical curriculum. MATERIALS AND METHODS The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 44 schools returned the completed survey resulting in a response rate of 82%. RESULTS Results from this survey show that the majority of schools (71%) teach the selective-pressure technique for final impression making; the majority of the schools (64%) use modeling plastic impression compound for border molding the final impression tray; 39% of the schools do not place vent holes in the final impression tray, 30% of schools place more than one hole and 27% place one hole only; the majority of the schools (98%) are using custom trays for final impressions. Ninety-eight percent of the schools are border molding the custom tray and 70% of schools are using a visible light-cured (VLC) composite resin material to make the trays. Thirty-six percent of the schools are teaching the Boucher impression technique and 34% are teaching the modified Boucher impression technique. CONCLUSIONS Predoctoral clinical complete denture educational programs agree on many aspects of final impression making, however, there is variability in their teachings regarding the impression philosophy and the materials used.

Preclinical complete dentures curriculum survey.

Purpose A survey of U.S. dental schools was conducted in 2001 to determine the curricular structure, teaching philosophies, and techniques used in preclinical complete denture courses. Materials and Methods The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 43 schools returned the completed survey, a response rate of 80%. The mean, median, and range of responses were computed where applicable. Results Results from this survey show that the mean student-to-faculty ratio in the preclinical course was 12:1, with a median of 12:1 and a range of 6:1 to 27:1. The mean number of laboratory hours was 74, with a median of 70.5 and a range of 31.5 to 160. The mean number of lecture hours reported was 28, with a median of 25 and a range 12 to 80. The mean number of practical examinations was 3, with a median of 3 and a range of 0 to 11. Eighty-four percent of the schools have prosthodontists teaching the course. The mean number of months that this course is taught is 5 months, with a median of 5 and a range of 2 to 13. Fifty-eight percent of the schools use the Hanau semiadjustable articulator. Sixty-five percent of the schools use protrusive records to set the articulator. The facebow preservation record is used by 84% of the schools. Conclusions Preclinical complete denture educational programs vary from school to school, yet a large percentage of schools agree on certain topics. Only 28% of dental schools are incorporating new technologies, such as the internet, in their preclinical complete denture curriculum. Nineteen percent of dental schools are using only the Portrait denture teeth, which are newer than the Bioblend and Bioform teeth.

Comparison of retention and strain energies of stud attachments for implant overdentures.

PURPOSE The retentive forces and the strain energies absorbed during dislodging of implant overdenture stud attachments are useful parameters to consider in the selection of attachments. The purpose of this study was to compare the retentive forces and strain energies of the Nobel Biocare standard ball, Nobel Biocare newer generation ball (Yorba Linda, CA), Zest Anchor, Zest Anchor Advanced Generation (Escondido, CA), Sterngold-Implamed ERA white, and Sterngold-Implamed orange attachments (Attleboro, MA) on an implant-retained in vitro overdenture model. MATERIALS AND METHODS The attachments were tested using two permanently placed Brånemark system implants on a test model attached to an Instron machine. Each attachment had one part embedded in a denture-like housing, and the other part screwed into the implants. Dislodging tensile forces were applied to the housings in two directions simulating function: vertical and oblique. Eight tests were done in two directions with six specimens of each attachment. Retentive forces generated and strain energies absorbed during displacement were determined. A 1-way ANOVA followed by the Tukey studentized range test was used to determine groups that were significantly different at the p < 0.05 level. RESULTS The Zest Anchor Advanced Generation attachment had significantly the highest retentive vertical and oblique forces [37.2 (5.5) N and 25.9 (3.2) N, respectively]. The Zest Anchor had the lowest vertical force [10.8 (4.2) N], and Nobel Biocare Standard had the lowest oblique retentive force [10.6 (3.0) N]. The Nobel Biocare Standard Ball attachment had the highest strain energies [29.7 × 10(-3) (11.9 × 10(-3)) J, 30.3 × 10(-3) (14.3 × 10(-3)) J, respectively, in the vertical and oblique directions]. The Sterngold-Implamed ERA White and Zest Anchor had the lowest strain energies [5.3 × 10(-3) (3.2 × 10(-3)) J and 4.5 × 10(-3) (1.1 × 10(-3)) J, respectively, in the vertical and oblique directions]. CONCLUSION The retentive forces and strain energies of implant overdenture stud attachments are different and should be considered during prosthesis selection.

Current concepts for determining the postpalatal seal in complete dentures

PURPOSE In 2001, a survey of U.S. dental schools was conducted to determine the concepts and techniques used for establishing the postpalatal seal (PPS) in a predoctoral dental curriculum. MATERIALS AND METHODS The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 44 returned the completed survey, resulting in a response rate of 82%. RESULTS Results from this survey show that 80% of the schools are teaching a combination of phonation with other methods for locating the vibrating line. The 1 vibrating line concept for establishing the PPS is taught by 80% of schools; 77% of these schools locate the posterior termination of the maxillary denture on the vibrating line. Carving the PPS in the maxillary master cast is taught by 95% of the schools. Most of the schools teach the students to carve the PPS to a depth of 1.0-1.5 mm in the maxillary master cast. Compressibility of the palatal tissues is a consideration during PPS carving for 91% of the schools. The butterfly pattern is the most frequently (75%) described pattern for PPS carving. CONCLUSIONS There is some variability from school to school on performing the PPS in the maxillary denture, although some trends are evident.

Preclinical removable partial dentures curriculum survey

PURPOSE In 2001, a survey of U.S. dental schools was conducted to determine the curricular structure, teaching philosophies, and techniques used in preclinical removable partial denture (RPD) courses and to also establish what newer educational techniques and materials are currently being used by U.S. dental schools. MATERIALS AND METHODS The questionnaire was mailed to the chairpersons of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 43 schools returned the completed survey, resulting in a response rate of 80%. The mean, median, and range of responses were computed where applicable. RESULTS Results from this survey show that the mean student-to-faculty ratio in the preclinical RPD course was 12:1, with a median of 10:1 and a range of 6:1 to 27:1. The mean number of laboratory hours was 55, with a median of 50 and a range of 13.5 to 120. The mean number of lecture hours reported was 21, with a median of 20.5 and a range 10 to 60. The mean number of practical examinations was 2, with a median of 3 and a range of 0 to 8. The mean number of written examinations given was 2, with a median of 2 and a range of 1 to 6. Ninety-five percent of the schools have prosthodontists teaching this course. The mean number of months that this course is taught is 4.4 months, with a median of 4 and a range of 1.5 to 10. Fifty-five percent of the schools used the Hanau semiadjustable articulator. One hundred percent of the schools teach students to use a surveyor when designing an RPD, and 84% percent of the schools teach the Krol or the Kratochvil RPI design or a combination of the 2 designs. CONCLUSIONS Preclinical RPD educational programs vary from school to school, yet a large percentage of schools agree on certain topics. Only 19% of dental schools are incorporating new technologies, such as the use of the internet, in their preclinical RPD curriculum.

A retrospective analysis of mandibular bone height changes associated with 81 screw-retained implant-supported prostheses with distal cantilevers: a long-term follow-up analysis.

PURPOSE The aims of this study were (1) to evaluate long-term changes in bone height beneath mandibular screw-retained implant-supported prostheses with distal cantilevers and (2) to determine whether the reversal of residual ridge resorption in the posterior mandible is temporary or continues over the long term. MATERIALS AND METHODS Panoramic radiographs, obtained at surgery and at two follow-up visits, of 81 patients rehabilitated with mandibular screw-retained implant-supported prostheses with distal cantilevers supported by four, five, or six implants were followed for 5 to 19 years (overall mean follow-up, 9.00 years. Changes and trends in bone height adjacent to the most distal implant were evaluated between each follow up visit as well as from time of surgery (baseline) to the final visit using two-way analysis of variance, a two-sample t test, and piecewise linear regression. RESULTS Average bone height distal to the distal most implant at placement was 10.34 ± 6.87 mm. From baseline to the first follow-up exam, a mean bone gain of 0.68 mm was noticed, and a mean gain of 0.26 mm was observed from baseline to the second follow-up exam. A statistically significant bone gain (0.92 mm) was noticed in women (n = 49) between the first and second exams, compared to 0.33 mm in men (n = 32). Individuals experienced both bone gain and loss during the study, with an overall gain. Patients with lower initial bone height experienced greater growth, but this was not statistically significant. CONCLUSION Bone growth is associated with mandibular screw-retained implant-supported prostheses with distal cantilevers, and both bone loss and bone growth may occur in the same patient over time. Within the diverse population of this study, women experienced 2.5 times more gain in bone height than men. No correlation could be established between initial bone height and overall bone height changes.

Treatment of a Patient with Cleidocranial Dysplasia Using a Single-Stage Implant Protocol

This patient report describes the treatment of a 45-year-old Caucasian woman with cleidocranial dysplasia who had significant dental problems that greatly affected her quality of life. The patient had orthodontic treatment in her earlier years along with surgical removal of supernumerary teeth. Using implants, the maxillary and mandibular arches were restored with fixed screw-retained prostheses. Eight implants and six implants were placed in the maxilla and mandible, respectively. Both arches were immediately loaded following the Teeth in a Day™ protocol using an all-acrylic resin provisional prosthesis. Five months later, definitive maxillary and mandibular prostheses were fabricated. The patient has been followed for a period of 5 years, and all postoperative evaluations have been uneventful.

Survey of recently board-certified prosthodontists on the board-certification process. Part 2: Preparation and impact

PURPOSE A 2-part survey of recently board-certified prosthodontists was conducted in 2001. The first part of the survey, published in June 2003, determined the trends that assisted the candidates in attaining diplomate status. The second part of the survey was done to determine the preparation methods and resources used to prepare for the examination, the most difficult part of the examination, the most gratifying aspect of becoming board-certified, their current employment status, and whether board certification had any positive impact on their employment. MATERIALS AND METHODS A questionnaire was mailed to 176 diplomates who had become board certified between the years 1993-2001. Of these, 131 board-certified prosthodontists returned the completed survey, resulting in a response rate of 74%. RESULTS Results from this survey showed that 91% of the diplomates had taken the American College of Prosthodontists (ACP) Board Preparation course; most of the diplomates (41%) prepared for the boards by reviewing prosthodontic literature, reading textbooks, using the ACP Study Guide, and seeking the help of other board-certified prosthodontists; 89% of the diplomates felt that achieving board certification had a positive influence in their employment; 39% of the diplomates indicated that Part 2 of the examination was the most difficult to prepare for, and 41% indicated that Part 2 was the most difficult section; the majority of diplomates (31%) were employed by the military, and the most gratifying aspect of becoming board-certified was personal accomplishment (83%). CONCLUSIONS Trends were observed regarding prosthodontists who succeeded with their efforts to challenge the board examination. The majority of the diplomates were employed by the military. Most of the respondents indicated that they took the ACP Board Preparation course and found it helpful. The largest percentage of respondents reported that Part 2 was both the most difficult part to prepare for, as well as the most difficult to complete. The most gratifying aspect of becoming board-certified was personal accomplishment.

Treatment of a Patient With Implant Failure and Jaw Osteonecrosis: Successful Retreatment Using Implants

C urrently, osteoporosis is on the rise, and is the most common disease of bone metabolism encountered in dental implant patients. Approximately one-third of patients over the age of 60 are affected, with woman incurring events twice as often as men. Alendronate sodium (Fosamax; Merck and Co, Whitehouse Station, NJ) is a secondgeneration nonhormonal bisphosphonate (BP) used in oraldose tablet form for osteopenic conditions. BPs possess a high affinity for bone inhibiting osteoclastic function and decrease bone resorption, preventing further bone loss. A possible complication of patients on bisphosphonates is osteonecrosis. Marx was the first who adopted the terminology to describe spontaneous or surgically induced nonhealing ulcers in the jaws that occur in patients taking bisphosphonates. This is termed bisphosphonate-induced osteonecrosis of the jaw (BONJ). According to the American Association of Oral and Maxillofacial Surgeons (AAOMS), the diagnosis of necrosis of the jaws induced by BP is based on the following criteria: (1) exposed bone greater than 8 weeks in duration; (2) it is induced by BP; and (3) no history of radiation therapy to the jaws. Although the initial effects of bisphosphonate therapy appear to be beneficial, with Merck & Co. reporting a 5.1% (alendronate, 70 mg/wk) mean increase in bone mineral density demonstrated over a 1-year period, the symptoms of BONJ may remain concealed for weeks or months, only to become recognizable by the presence of exposed bone in the oral cavity. Due to the common occurrence of tooth extraction, resulting in exposed bone, there exists a legitimate reason for concern and raises natural questions about alendronate’s effects on dental implant osseointegration. Currently, BONJ is considered long term and irreversible, despite attempts to discontinue medication usage. Little data has been collected on oral bisphosphonate-related osteonecrosis and dental implant failure along with management of these failures. Most of the reported cases were from IVadministered BPs. In the United States, there have been over 200 reported cases of possible bisphosphonate associated osteonecrosis of the jaw in patients taking Fosamax or Actonel (Procter and Gamble, Cincinnati, Ohio). This report discusses a patient taking oral Fosamax for 1 year and having successful implant osseointegration in the maxillary arch while after 5 years on this medication, the patient developed BONJ when implants were placed and loaded in the mandibular arch. The aim of this case study is to present the ongoing management of a patient who prophylactically utilized the bisphosphonate (Fosamax) and developed BONJ and how retreatment with dental implants can be successful following a drug hiatus.

Survey of recently board-certified prosthodontists on the board certification process. Part 1: Demographics.

PURPOSE A survey of recently board-certified prosthodontists was conducted in 2001. The purpose of this survey was to identify trends that assisted candidates in attaining diplomate status. MATERIALS AND METHODS A questionnaire was mailed to 176 diplomates who had become board certified between the years 1993 and 2001. Of these, 131 board-certified prosthodontists returned the completed survey, resulting in a response rate of 74%. The mean, median, and range of responses were computed when applicable. RESULTS Results from this survey show that the mean number of years from completion of a postdoctoral program to achieving board certification was 6 years, with a median of 4 years and a range of 1 to 23 years. The mean number of years from the time of completion of a postdoctoral program to board eligibility was 2.3 years, with a median of 1 year and a range of 0 to 22 years. The mean number of years from board eligibility to board certification was 3.9 years, with a median of 3 years and a range of 0 to 17 years. The military was the most frequently reported employment status at the time the respondents took Parts 1-4 of the boards. A total of 54% of the diplomates reported that they challenged Part 1 separately, and then challenged Parts 2, 3, and 4 together; 79% of the diplomates were encouraged by their graduate program director/faculty to challenge the board; and 48% of the diplomates reported that their patients received free dental treatment. CONCLUSIONS Certain trends were observed regarding diplomates who succeeded in their efforts to challenge the board examination. The largest group who challenged the board certification examinations comprised members of the armed forces. Most prosthodontists challenged Part 1 before challenging the remaining 3 parts. In an effort to encourage more prosthodontists to challenge the board examination, numerous changes were made between 1992 and 1998; however, most of the diplomates did not take advantage of those changes.