Damian J. Lee

Electrochemical behavior of titanium in artificial saliva: Influence of pH

Titanium is the most common material chosen for dental implants because it is highly corrosion resistant because it constantly reforms a protective passive film layer. The formation and composition of the passive film layer is dependent on the environmental conditions. If the stable oxide layer is damaged, the titanium surface underneath can corrode. The purpose of this study was to determine if basic corrosion of commercially pure titanium (CpTi) alloy in artificial saliva was affected by pH and to understand the corrosion kinetics/mechanisms of CpTi as a function of pH. In this study, titanium alloy discs were subjected to corrosion tests. Before the tests, all samples were cleaned and polished using standard metallographic preparation methods. Artificial saliva was used as the testing medium. The following pH values were tested: 3.0, 4.5, 6.0, 6.5, 7.5, and 9.0. Different pH values were achieved by adding lactic acid (acidic) or NaOH (basic) in appropriate amounts. Potentiodynamic curves indicated behavior change at each pH. In addition, the corrosion current density value determined from the potentiodynamic curve exhibited the poorest corrosion resistance for pH 7.5. The Nyquist plot (from the electrochemical impedance spectroscopy results) indicated that pH 7.5 had the poorest resistance. Scanning electron microscopy images indicated that pH levels of 6.5, 7.5, and 9.0 had considerable surface corrosion. The results showed that the medias pH significantly influenced the corrosion behavior of CpTi. The poor corrosion behavior at the neutral pHs invites some concerns and highlights the need for further study.

Transcultural adaptation and testing psychometric properties of the Korean version of the Foot and Ankle Outcome Score (FAOS)

This study was performed to translate and transculturally adapt the English version of the Foot and Ankle Outcome Score (FAOS) into a Korean version, and to test psychometric properties of the Korean FAOS in terms of internal consistency, test–retest reliability, convergent validity, and dimensionality. Translation and transcultural adaptation of FAOS into a Korean version was performed according to internationally recommended guidelines. Internal consistency (N = 294) and test–retest reliability (N = 21) were evaluated. Convergent validity was analyzed using correlation with pain visual analogue scale (VAS) score. All subscales, except for the quality of life (Q) subscale (Cronbach’s alpha, 0.615), showed satisfactory internal consistency (Cronbach’s alpha > 0.7). Cronbach’s alpha of function in daily living (ADL) was highest (0.962), which might represent the redundancy of the items. All five subscales showed satisfactory reliability with ADL subscale showing the highest ICC (intraclass correlation coefficient; 0.851) and Q subscale the lowest ICC (0.718). Pain VAS score showed the highest correlation with pain (P) subscale of FAOS (r = 0.675, p < 0.001) and the lowest correlation with Q subscale (r = 0.495, p < 0.001). In the dimensionality test, a factor analysis was performed using the total items to rank their relative significance, which showed seven components solution. Considerable portion of the items showed a similar dimension according to their original subscales, except for ADL items. Translation and transcultural adaptation of FAOS into the Korean language was performed successfully. The items were understandable, and the subscales showed satisfactory test–retest reliability. Some minor revision might be needed to enhance the internal consistency of Q subscale and reduce the redundancy of ADL subscale.

Transcultural adaptation and testing of psychometric properties of the Korean version of the Hip Disability and Osteoarthritis Outcome Score (HOOS)

OBJECTIVE Translation and transcultural adaptation of the Hip Disability and Osteoarthritis Outcome Score (HOOS LK 2.0) into Korean language was performed, followed by test of psychometric properties. DESIGN A Korean version of the HOOS was produced according to internationally recommended guidelines, which included forward translation, reconciliation, back translation, harmonization, cognitive debriefing and proof reading. The psychometric properties including reliability and validity were evaluated. The reliability, including the internal consistency and test-retest reliability, was then evaluated in a hip osteoarthritis population (OA group, n=75). The validity, including the convergent validity was assessed comparing HOOS with the Short Form-36 (SF-36) and pain on a visual analogue scale (VAS) scale. Responsiveness was evaluated in a population scheduled for total hip arthroplasty (THA group, n=35). RESULTS All subscales of the HOOS showed satisfactory internal consistency (Cronbachs alpha>0.7) without floor and ceiling effects. Intraclass correlation coefficient (ICC) spanned from 0.78 to 0.93. In terms of convergent validity, Activity of Daily Living (ADL) subscale showed the strongest correlations with Physical Function (PF) (r=0.801) and Bodily Pain (BP) (r=0.810) in the subscales of SF-36. For responsiveness, all HOOS subscale scores improved significantly (P<0.05) postoperatively. CONCLUSIONS The Korean version of HOOS showed satisfactory internal consistency, test-retest reliability, convergent validity, and responsiveness. This study shows that the HOOS questionnaire developed in West is, with transcultural adaptation, relevant for use among patients in East Asia.

An Analysis of Prosthodontic Research Productivity: Geographic, Economic, and Collaborative Perspective

PURPOSE This study evaluated the quantity of prosthodontic literature produced globally by continent in three prosthodontic journals over a 10-year period, 1998-2008. Prosthodontic research productivity relative to economic status of countries and collaboration among countries grouped by economic status was assessed. MATERIALS AND METHODS Three peer-reviewed prosthodontic journals were used for the analysis of articles published in 1998, 2003, and 2008: The Journal of Prosthetic Dentistry, International Journal of Prosthodontics, and Journal of Prosthodontics. The country of every author listed for each included article was recorded. The number of articles published by each continent and each country was reported. Countries were grouped according to the World Bank economic classification system, and the number of articles published by each economic class was found. RESULTS The majority of publications over the 10-year period were produced in Asia (Japan), Europe (Germany), and North America (USA). Productivity declined by 14.4% in high-income countries while it increased in upper middle-, lower middle-, and low-income countries. The majority of publications written by upper and lower middle- and low-income countries were independent works. Articles resulting from collaboration increased over time for all economic classes of countries. CONCLUSIONS The origins of prosthodontic literature are becoming more geographically and economically diverse, with increased contributions from Africa, Asia, and South America, and middle- and low-income countries between 1998 and 2008. Collaboration between high-income countries and the other economic group countries increased over time.

Analysis of Abstracts Presented at the Prosthodontic Research Section of IADR General Sessions 2004-2005: Demographics, Publication Rates, and Factors Contributing to Publication

PURPOSE The purposes of this study were to describe the demographics of abstracts presented at the prosthodontics section of IADR General Sessions from 2004 to 2005, evaluate the publication rate of abstracts, and analyze the relationship between variables in abstracts and publication. MATERIALS AND METHODS Prosthodontics research section abstracts from the IADR General Session in 2004 and 2005 were evaluated for: number of authors, presentation type, origin, affiliation, topic, study design, statistics, study outcome, and funding. The publication rate was calculated following a PubMed search. The journal of publication, year of publication, and the length of time before publication were analyzed. Descriptive statistics were used for the data analysis; the relationships between presentation type, study design, study outcome, statistics, funding, and publication were analyzed using logistic regression (α= 0.05). RESULTS From 346 abstracts, 37.0% were published. For oral presentations, 40.7% were published; 35.8% of poster presentations were published. The mean duration before publication was 26.4 months. North America had the most abstracts, and Europe had the most publications. Fixed prosthodontic research had the highest number and proportion for publication. A significant association with publication was noted for neutral study outcomes (p= 0.018), studies with funding (p= 0.035), and abstracts from Europe (p= 0.001). CONCLUSIONS The majority of abstracts from the prosthodontics research section of IADR General Sessions from 2004 and 2005 remain unpublished. A significant association for publication was noted with neutral outcomes, funding, and abstracts from Europe.

Resident selection criteria for advanced education in prosthodontic programs: program directors' perspective.

PURPOSE The purpose of this study was to describe the criteria used by advanced education in prosthodontic program (AEPP) directors to select their residents, to rank them by perceived importance, and further assist prospective candidates with the application process for AEPP. MATERIALS AND METHODS Questionnaires were distributed to all prosthodontic program directors (N = 46). The program directors were requested to respond in five sections: (1) general information, (2) information obtained from applications and letters of recommendation, (3) interview process, (4) decision process, and (5) retrospective view of the selection process. Descriptive statistics were used to analyze the data. Data were collected and compiled into mean, standard deviation, and range. Results were tabulated and ranked. RESULTS Thirty-eight responses (82.61%) were returned and analyzed. Most of the programs (75.77%) indicated that a combination of the program director, current residents, prosthodontic faculty, and staff members were involved in conducting the interview process. Factors considered very important when choosing applicants to the prosthodontic program were (1) interview process, (2) dental school class rank, (3) dental school grades (prosthodontics), (4) letters of recommendation, (5) dental school grades (clinical). Letters from the prosthodontic post-doc program director and prosthodontic faculty were considered the most important source of recommendation. Honesty, organization, and energy were ranked as the most positive characteristics of the applicants during the interview. Almost all respondents (97%) were satisfied with the current selection process. When asked about the current applicant pool, most program directors (91.67%) were satisfied. CONCLUSIONS The most and least important factors in selecting applicants by the program directors were described and ranked. This study was intended to provide the profession with some insight on how advanced Prosthodontic programs select their applicants. It may also serve as a valuable instrument for prospective applicants to AEPPs in the future.

Transcultural adaptation and validation of the Korean version of the Pediatric Outcomes Data Collection Instrument (PODCI) in children and adolescents.

Background Translation and transcultural adaptation of the Pediatric Outcomes Data Collection Instrument (PODCI) into Korean language was performed, and the validity was tested. Methods Korean version of PODCI was produced according to internationally accepted guideline, which included preparation, forward translation, reconciliation, back translation, review of back translation and harmonization, cognitive debriefing and review, and proof reading process. Eighty-two child controls (aged 5 to 10 y), 92 adolescent controls (aged 10 to 18 y), and 30 children with cerebral palsy (aged 5 to 10 y) undergoing single event multilevel surgery were included, and their parents also participated. Each subscale of Korean PODCI was tested in terms of internal consistency (Cronbach &agr;), discriminant validity (difference of parental responses between child control and children with cerebral palsy), convergent validity (correlation between self-response and parental response in adolescent control), and responsiveness (postoperative changes of parental responses in children with cerebral palsy). Results All subscales except pain/comfort showed sufficient internal consistencies (Cronbach &agr;>0.7). Upper extremity/physical function, transfer/basic mobility, sports/physical functioning, and global functioning subscales showed significant discriminant validity (P<0.001, P<0.001, P<0.001, and P<0.001, respectively). Correlation between self-response and parental response in adolescent controls were significant in all subscales, being highest in transfer/basic mobility subscale (r=0.952, P<0.001) and lowest in happiness subscale (r=0.548, P<0.001). Responsiveness was significant in transfer/basic mobility (P<0.001), sports/physical functioning (P=0.001), and global functioning (P=0.006) subscales after single event multilevel surgery. Conclusions Korean version of PODCI showed relevant internal consistency, discriminant validity, convergent validity, and responsiveness except for pain/comfort and happiness subscales. Care need to be taken when evaluating subjective measures, such as pain/comfort and happiness subscales. Level of Evidence Diagnostic level I.

Retrospective analysis of dental implants placed and restored by advanced prosthodontic residents.

PURPOSE The purposes of this retrospective clinical review were to: (1) describe the demographics of implant patients, types of implant treatment and implant-supported prostheses in an Advanced Education in Prosthodontic Program, (2) evaluate the survival rate of dental implants placed by prosthodontic residents from 2006 to 2008, and (3) analyze the relationship between resident year of training and implant survival rate. MATERIAL AND METHODS All patients who received dental implants placed by prosthodontic residents from January 2006 to October of 2008 in the Advanced Prosthodontic Program at the University of Illinois at Chicago College of Dentistry were selected for this study. Age, gender, implant diameter, length, implant locations, surgical and restorative detail, and year of prosthodontic residency training were collected and analyzed. Life-table and Kaplan-Meier survival analyses were performed based on implants overall, locations, year of training, and use of a computer-generated surgical guide. A Logrank statistic was performed between implant survival and year of prosthodontic residency training, location, and use of computer-generated surgical guide (α= 0.05). RESULTS Three hundred and six implants were placed, and of these, seven failed. Life-table and Kaplan-Meier analyses computed a cumulative survival rate (CSR) of 97% for overall implants and implants placed with a computer-generated surgical guide. No statistical difference was found in implant survival rates as a function of year of training (P= 0.85). CONCLUSION Dental implants placed by prosthodontic residents had a CSR comparable to previously published studies by other specialties. The year of prosthodontic residency training and implant failure rate did not have any significant relationship.

Applicant selection procedures for orthodontic specialty programs in the United States: Survey of program directors

INTRODUCTION With the recent changes in scoring of the National Board Dental Examinations and grading systems in some dental schools, ranking prospective orthodontic applicants has become a challenge. METHODS A 31-item survey was sent to orthodontic program directors in the United States to determine admission practices of all accredited specialty orthodontic programs. RESULTS Forty-four of 64 program directors responded (69%). This study showed a wide variation of admission practices among these programs. The only consistent part of admissions in all programs was the interview process. The top factors considered for each applicant were interview ratings, dental school class rank, and letters of recommendation. The top sources of recommendations were the orthodontic department chair, the graduate program director, and the predoctoral orthodontic program director. The top 3 character traits considered most favorable were maturity, and good verbal and listening skills. CONCLUSIONS Accredited orthodontic programs in the United States follow different procedures in assessing applicants for admission. It is important to consider both academic and nonacademic measures in assessing applicant information in a standardized manner to ensure a fair and efficient selection process.

An alternative approach for the management of fractured implant abutment screws on a mandibular implant-retained overdenture: A clinical report

In contemporary implant and prosthodontic practice, high levels of surgical and biologic success rates have been achieved. However, mechanical and technical complications continue to exist. Of these, one of the biggest challenges to the clinician is the conservative retrieval of fractured screw fragments from within the implants and/or abutments. While removal is desirable, the fragments cannot always be removed, and alternative solutions for the management of such clinical situations must be considered. This clinical report describes the replacement of 2 fractured, irretrievable, Locator abutment screws of a mandibular implant-retained overdenture with a cast dowel and laser welded Locator attachments. This alternative method was successful in managing broken abutment screw fragments while using the existing prosthesis and implants.