A novel approach for effective integration of new faculty leadership.

PURPOSE: We report on an accelerated and effective way of assimilating a new leader into a team at a large academic dental school department. METHODS: At University of California, San Francisco (UCSF), a new Chair was recruited through a national search to lead its largest department in the School of Dentistry. Two months after arrival, the new Chair embarked on a process of leadership assimilation among her executive team, facilitated by a professional consultant. Within four weeks, team members participated in one-on-one interviews with the professional facilitator consultant and then completed the leadership assimilation questionnaire and returned it electronically to the facilitator. The facilitator then summarized all answers into themes and met with the team members without the Chair to debrief. Thereafter, the facilitator met with the Chair to discuss the major themes. Next, the Chair met with the team members in a facilitated session to discuss the results and negotiate a path forward. RESULTS: Approximately half of the feedback described the "how" of leadership: comments on communication, building relationships, building trust, and understanding UCSF history. The remaining half described the "what": comments on vision, strategy, and operations. Team members indicated that the first debriefing session was helpful to alleviate initial anxiety and to start building team spirit. The session with the Chair was perceived as open and fruitful in which team members were able to express their concerns and hopes for the Department, while the Chair showed commitment to the team and the communication process. CONCLUSION: Leader assimilation allows teams to share their expectations and anxieties with the new leader early in the relationship in an open way, before new habits and beliefs are formed. Conversely, for the leader, it effectively and efficiently allows a window into the team members' thinking at a critical time period when otherwise first impressions occur. With a safe space created for open communication, the process allowed siloed individual division leaders to move toward a cohesive group while at the same time solidifying a commitment to the success of the new leader.

Laser all-ceramic crown removal-a laboratory proof-of-principle study-phase 1 material characteristics.

BACKGROUND AND OBJECTIVES: The removal of all-ceramic crowns is a time consuming and destructive procedure in the dental office. The removal of all-ceramic crowns using Er:YAG lasers has not been previously described in the scientific literature. The objective of this laboratory proof-of-principle study was to evaluate whether with regards to absorption and transmission characteristics of bonding cements and ceramics all-ceramic crowns can be removed from natural teeth using an Erbium laser. STUDY DESIGN/MATERIALS AND METHODS: The Fourier Transform Infrared Spectroscopy (FTIR) was used on flat ceramic samples (IPS Empress Esthetic (EE), E.max CAD, and E.max ZirCAD) to assess which infrared laser wavelengths transmit through the ceramics. Additionally, FTIR spectra for four bonding cements (Variolink Veneer, Variolink II, Multilink Automix, and SpeedCEM) were obtained. The Er:YAG laser energy transmission (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µs at 126 mJ/pulse to 300 µs at 508 mJ/pulse) through different ceramic thicknesses was measured. Ablation thresholds for bonding cements were determined. Cement samples were directly irradiated or laser light was transmitted through ceramic samples. RESULTS: While the ceramics did not show any characteristic water absorption bands in the FTIR, all bonding cements showed a broad H2 O/OH absorption band. Some cements exhibited a distinct absorption peak at the Er:YAG laser emission wavelength. Depending on the ceramic thickness, EE and E.max CAD ceramics transmitted between 21 and 60% of the incident Er:YAG energy, with E.max CAD transmitting more energy than EE at comparable thicknesses. In contrast, E.max ZirCAD transmitted only 5-10% of the incident energy. Initial signs of cement deterioration occurred at 1.3-2.6 J/cm(2) . Multilink Automix, SpeedCEM, and Variolink II started ablation at 4.4-4.7 J/cm(2) . Variolink Veneer needed 44% less energy for ablation. CONCLUSION: Er:YAG laser energy can be transmitted through all-ceramic materials and those transmitted energies are sufficient for ablation of bonding cements.

Laser all-ceramic crown removal-a laboratory proof-of-principle study-phase 2 crown debonding time.

BACKGROUND AND OBJECTIVES: The removal of all-ceramic crowns is a time consuming procedure in the dental office. Little research has been done in alternative removal techniques for all-ceramic crowns. The objective of the second phase of this proof-of-principle laboratory pilot study was to evaluate whether Ivoclar Vivadent all-ceramic crowns can be efficiently removed from natural teeth without damage to the underlying tooth structure using an Erbium laser. STUDY DESIGN/MATERIALS AND METHODS: The ceramic materials used were IPS E.max CAD Lithium-disilicate (LS2 ) (E.max CAD) and IPS E.max ZirCAD Zirconium-oxide (ZrO2 ) (ZirCAD) (Ivoclar, Vivadent, Liechtenstein). Molars, either as stand-alone teeth or placed in an artificial row of teeth, were prepared to receive all-ceramic crowns. Copings and full contour crowns with either featheredge or regular margins were produced. The all-ceramic crowns were bonded to the teeth with Ivoclar Multilink Automix. The time for Er:YAG laser debonding of each crown was then measured. The Er:YAG (LiteTouch, Syneron, Yokneam, Israel) was used with an 1,100 µm diameter fiber tip with energies up to 600 mJ per pulse (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µs at 126 mJ/pulse, and 400 µs at 590 mJ/pulse). The irradiation was applied at a distance of 10 mm from the crown surface following a defined pattern. Air-water spray was applied to the crowns at a rate of 67 ml/minute. RESULTS: All of the all-ceramic crowns were successfully debonded with the laser. On average, an all-ceramic E.max CAD crown was debonded in 190 ± 92 seconds (average ± SD). The debonding time for ZirCAD featheredge crowns was 226 ± 105 seconds and for ZirCAD crowns with regular margins it was 312 ± 102 seconds. No crowns fractured and no damage to the underlying dentin was detected. The bonding cement deteriorated due to the Er:YAG irradiation. Additionally, no carbonization at the dentin/cement interface was observed. CONCLUSION: Er:YAG laser energy can successfully be used to efficiently debond all-ceramic full contour crowns from natural teeth without damage to the underlying tooth structure. Lasers Surg. Med. 46:636-643, 2014. © 2014 Wiley Periodicals, Inc.

Assessing fit at the implant-abutment junction with a radiographic device that does not require access to the implant body.

STATEMENT OF PROBLEM: Radiograph paralleling devices provide an excellent means of obtaining orthogonal radiographs for the evaluation of the fit of implant restorations. Unfortunately, the clinical applicability of such devices is a significant issue because access to the implant body must be obtained at each radiographic appointment. PURPOSE: The purpose of the study was to investigate whether the fit or microgap at the implant-abutment junction could be more accurately and confidently assessed with a novel radiograph paralleling device that did not require access to the implant body once a proper registration index was made. MATERIAL AND METHODS: Microgaps of 0, 50, and 100 µm were introduced at the implant-abutment junction of a provisional implant crown in a manikin-typodont assembly. Dental assistants made 54 radiographs (18 per microgap) of the crown with and without a radiograph paralleling device; 9 clinicians then evaluated the standardized radiographs for the presence of misfit. The Cochran-Mantel-Haenszel test and the corresponding odds ratios were used to evaluate the effectiveness of the paralleling device in helping clinicians better assess misfit from the radiographs made. RESULTS: The use of the device led to a higher percentage of accuracy under all conditions (79.0% vs 70.4% at the 0-µm gap, 77.8% vs 16.1% at the 50-µm gap, and 100% vs 92.6% at the 100-µm gap); the improvement was statistically significant at the 50-µm gap (P<.001) and 100-µm gap (P=.049) but not at the 0-µm gap (P=.364). The odds ratio (95% confidence interval) of obtaining correct versus wrong answers with the device compared with without the device was 18.64 (7.94-43.77) at the 50-µm gap and 5.40 (0.25-114.25) at the 100-µm gap. CONCLUSIONS: The study indicated that the paralleling device helped the clinician more accurately assess the implant-abutment junction with the 50- and 100-µm gaps.

A radiograph positioning technique to evaluate prosthetic misfit and bone loss around implants.

A radiograph positioning device was developed to fit with commercially available film holders and implant systems. The device is indexed to the dental implant body and the adjacent dentition by using an implant placement driver and polyvinyl siloxane occlusal registration material. By fitting the device to a conventional film holder, accurate orthogonal radiographs can monitor changes in bone architecture and prosthetic misfit.

The effect of E-glass fibers and acrylic resin thickness on fracture load in a simulated implant-supported overdenture prosthesis.

STATEMENT OF PROBLEM: Implant overdenture prostheses are prone to acrylic resin fracture because of space limitations around the implant overdenture components. PURPOSE: The purpose of this study was to evaluate the influence of E-glass fibers and acrylic resin thickness in resisting acrylic resin fracture around a simulated overdenture abutment. MATERIAL AND METHODS: A model was developed to simulate the clinical situation of an implant overdenture abutment with varying acrylic resin thickness (1.5 or 3.0 mm) with or without E-glass fiber reinforcement. Forty-eight specimens with an underlying simulated abutment were divided into 4 groups (n=12): 1.5 mm acrylic resin without E-glass fibers identified as thin with no E-glass fiber mesh (TN-N); 1.5 mm acrylic resin with E-glass fibers identified as thin with E-glass fiber mesh (TN-F); 3.0 mm acrylic resin without E-glass fibers identified as thick without E-glass fiber mesh (TK-N); and 3.0 mm acrylic resin with E-glass fibers identified as thick with E-glass fiber mesh (TK-F). All specimens were submitted to a 3-point bending test and fracture loads (N) were analyzed with a 2-way ANOVA and Tukey's post hoc test (α=.05). RESULTS: The results revealed significant differences in fracture load among the 4 groups, with significant effects from both thickness (P<.001) and inclusion of the mesh (P<.001). Results demonstrated no interaction between mesh and thickness (P=.690). The TN-N: 39 ±5 N; TN-F: 50 ±6.9 N; TK-N: 162 ±13 N; and TK-F: 193 ±21 N groups were all statistically different (P<.001). CONCLUSIONS: The fracture load of a processed, acrylic resin implant-supported overdenture can be significantly increased by the addition of E-glass fibers even when using thin acrylic resin sections. On a relative basis, the increase in fracture load was similar when adding E-glass fibers or increasing acrylic resin thickness.

Er:YAG laser debonding of porcelain veneers.

BACKGROUND AND OBJECTIVES: The removal of porcelain veneers using Er:YAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate the efficacy of an Er:YAG laser on veneer debonding, possibly without damage to the underlying tooth, and preservation of the veneer integrity. STUDY DESIGN/MATERIALS AND METHODS: The Fourier Transform Infrared Spectroscopy was used on 10 flat veneer samples (IPS Empress Esthetic, e.max Press HT) to assess which infrared laser wavelengths transmits through a veneer. Additionally, Fourier Transform Infrared (FTIR) spectra for a bonding cement (RelyX) were obtained. Consequently, Er:YAG laser energy transmission (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µseconds at 133 mJ/pulse) through different veneer thicknesses was measured. Twenty-four veneers were bonded to freshly extracted and prepared incisors. The energy necessary for debonding was determined and then the veneers were debonded with the laser. Time needed for total debonding was measured and possible damage to the underlying tooth structure was assessed by light microscopy. RESULTS: While the veneer materials did not show any characteristic water absorption bands in the FTIR, the bonding cement showed a broad H(2) O/OH absorption band. The veneers transmitted between 11.5% and 43.7% of the incident Er:YAG energy with Emax transmitting twice the energy as EE at comparable thicknesses. Initial signs of cement ablation occurred at 1.8-4.0 J/cm(2) with the fiber tip positioned at a distance of 3-6 mm from the veneer surface and 133 mJ output energy. All 24 bonded veneers were completely removed with an average removal time of 113 ± 76 seconds. Underlying tooth structure was not damaged. The debonding mainly occurred at the cement/veneer interface. None of the Emax veneers fractured during debonding, while 36% of the EE did. CONCLUSION: Er:YAG laser irradiation effectively debonds porcelain veneers while preserving tooth structure. Maintaining veneer integrity possibly depends on the flexure strength of the veneer porcelain.

The effects of an airborne-particle abrasion and silica-coating on the bond strength between grooved titanium alloy temporary cylinders and provisional veneering materials.

STATEMENT OF PROBLEM: Even though mechanical retentive features, such as grooves, are incorporated into the surface of titanium alloy temporary cylinders, a reliable bond to veneering provisional materials is not always achievable for screw-retained provisional implant restorations. There is insufficient information about the effect of tribochemical silica coating on the bond strength between provisional materials and grooved titanium alloy temporary cylinders. PURPOSE: The purpose of this study was to evaluate, in vitro, the effect of an airborne-particle abrasion and silica-coating technique on the bond strength between grooved titanium alloy temporary cylinders and provisional veneering bisphenol-A glycidyl methacrylate and polymethyl methacrylate materials. MATERIAL AND METHODS: Forty grooved titanium alloy (Ti-6Al-4V) internal connection implant temporary cylinders were used. A disc of veneering material (7.1 × 3.4 mm) was created around the midsection of each cylinder. Forty specimens were divided into 4 groups (n=10): group NoTxPMMA, no surface treatment and polymethyl methacrylate veneering material; group NoTxBisGMA, no surface treatment and BisGMA veneering material; group AbPMMA, airborne-particle abrasion, silica-coating surface treatment (Rocatec), and polymethyl methacrylate; and group AbBisGMA, airborne-particle abrasion, silica-coating surface treatment (Rocatec), and BisGMA. Each specimen was subjected to ultimate shear load testing at the interface of the veneering material and the temporary cylinder in a universal testing machine at a constant crosshead speed of 5 mm/min. Data were analyzed with a 1-way ANOVA (α=.05) followed by post hoc Student-Newman-Keuls test. Each specimen underwent surface observation with a light microscope at ×40 magnification to compare fracture patterns. RESULTS: Airborne-particle abrasion and silica-coating surface treatment significantly lowered the shear bond strength (P<.05). The type of provisional material did not significantly affect the shear bond strength, with or without surface treatment. Group AbBisGMA demonstrated the lowest mean value (3.49 MPa) compared to the other groups. CONCLUSIONS: Airborne-particle abrasion and silica-coating treatment did not improve the bond between grooved titanium alloy temporary cylinders and provisional veneering materials. It weakened the provided mechanical retention, especially when it was used with BisGMA veneering material. Material choice, whether it was polymethyl methacrylate or BisGMA, did not make a statistically significant difference.

The use of dental implants to improve quality of life for edentulous patients.

The number of edentulous patients in the United States requiring prosthodontic care is projected to increase in the next 20 years. Awareness of the restorative options to manage edentulous patients will become increasingly important to all dental practitioners. The authors' purpose is to sensitize the reader to the functional deficit in the completely edentulous patient and how restorative approaches with implants can improve patient reports of function and quality of life.

Transitioning patients: teeth to implants.

The transition of patients from a dentate state to an implant-supported restoration requires significant planning. Traditionally, protocols have included the extraction of teeth and interim use of a removable prosthesis. Newer protocols include approaches to decrease the period of time a patient is required to use a traditional denture. The authors' purpose is to outline options and provide clinical examples when transitioning patients from natural dentition to an implant-supported prosthesis.

Dental students' self-assessment of preclinical examinations.

Accurate self-assessment is an important attribute for practicing dentists and, therefore, an important skill to develop in dental students. Our purpose was to examine the relationship between faculty and student assessments of preclinical prosthodontic procedures. Seventy-six second-year students completed two consecutive examinations and two self-assessments. The examinations involved setting maxillary denture teeth on a model to simulate the clinical procedure of a complete maxillary denture. Results indicated no significant increases in examination or student self-assessment mean scores; however, regression analysis indicated changes in student self-assessment scores explained 16.3 percent of the variation in examination scores. In essence, improvement in student self-assessment predicted improvement in examination scores among dental students completing a preclinical dental procedure.

Correlation of admissions criteria with academic performance in dental students.

Our purpose was to compare admissions criteria as predictors of dental school performance in underachieving and normally tracking dental students. Underachieving dental students were identified by selecting ten students with the lowest class grade point average following the first year of dental school from five classes, resulting in a pool of fifty students. Normally tracking students served as a control and were randomly selected from students who had completed their first year of dental school not in the underachieving group. Admission measures of college grade point average (GPA), science grade point average (SGPA), academic average (AA), Perceptual Ability Test (PAT), college rigor, and academic load in college were evaluated with descriptive statistics, correlation, and regression analysis with first-year and graduating GPA as the dependent variables. Admissions criteria were generally weak predictors of first-year and graduating GPA. However, first-year dental school GPA was a strong predictor (R(2)=0.77) of graduating GPA for normally tracking students and a moderate predictor (R(2)=0.58) for underachieving students. Students who completed the first year of dental school having a low GPA tended to graduate with a low GPA. Therefore, remediation and monitoring would be important during the dental school experience for these students.

The correlation of student performance in preclinical and clinical prosthodontic assessments.

Tracking student performance in preclinical and clinical courses can be helpful in developing and refining a curriculum. Our objective was to correlate student performance on three fixed prosthodontic examinations taken by eighty junior dental students. Examinations included a knowledge-based objective structured clinical examination (OSCE), a manual skills exercise completed on a typodont (Typodont), and a competency casting exam (Casting CE) on a patient. Multiple regression analysis indicated that the OSCE and Typodont exam scores, as independent variables, were not statistically significant predictors (P=0.07; P=0.87, respectively) of Casting CE exam performance, which was the dependent variable. Correlations were weak for the OSCE (r=0.21) and nearly nonexistent for the Typodont exam(r=0.03) when compared to the Casting CE. Our results indicate a weak correlation between an OSCE-based knowledge exam measuring students' knowledge of critical errors in preparations and castings and a competency exam involving the preparation of a full veneer crown. Results also indicate virtually no correlation between a typodont preparation examination designed to provide a measure of students' clinical skill and a clinical competency exam involving the preparation of a full crown.

Complications associated with fixed partial dentures with a loose retainer.

STATEMENT OF PROBLEM: When 1 retainer of a definitive fixed partial denture (FPD) becomes loose, the clinician has the option of either sectioning and removing the FPD or attempting removal of the intact cemented retainer. Excessive force during attempted FPD removal may irreversibly damage dentition. PURPOSE: This study evaluated the type and frequency of complications that may accompany the removal of definitive cemented FPDs with a single loose retainer. MATERIAL AND METHODS: Participants included 22 patients with a definitive cemented FPD with complete cast crown coverage castings in which 1 retainer became loose and the other retainer remained cemented. Cemented FPD retainers were removed using 1 of 2 attachments supplied with a crown removal system (Dentco). The patient and FPD characteristics, type of attachment, number of attempts before removal, condition of removed FPD, and condition of the abutment teeth were recorded. Descriptive statistics were used to analyze the data. RESULTS: Clinical findings recorded prior to FPD removal showed that 41% of patients were unaware they had a loose FPD retainer and 82% reported no discomfort associated with the loose retainer. Caries were noted on 50% of the teeth with a loose retainer. Damage resulting from attempted removal of the cemented retainer included minor porcelain fracture (9%), minor core chipping (14%), minor incisal edge chipping of tooth preparations (27%), and major damage to the abutment tooth (4%). CONCLUSION: Retrieval of an intact FPD and recementation was possible 64% of the time.