Staged Reconstruction (Delayed-Immediate) of the Maxillectomy Defect Using CAD/CAM Technology.

BACKGROUND: Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has become increasingly popular for free fibula reconstruction of the mandible. The same technology, however, has not been widely utilized in immediate complex midface reconstruction utilizing free fibula flaps. Maxillary defects are difficult to precisely predict or produce matched cutting guides for after the ablative surgery. We present a protocol for "delayed-immediate" two-stage reconstruction for complex mid-facial defects, by delaying lymph node neck dissection and using CAD/CAM technology for delayed bony reconstruction. METHODS: Stage 1 includes the extirpative surgery, placement of a temporary obturator, and an immediate post-excision fine cut computed tomography (CT) of the defect that is used for CAD/CAM planning. The time interval between stages is used for virtual surgical planning (VSP) and provides an opportunity for the final pathologic margins to be evaluated. At stage 2, definitive reconstruction is performed in conjunction with the delayed neck dissection. Briefly delaying the neck dissection until stage 2 allows for recipient vessel dissection and microsurgical anastomoses to safely occur in a surgically naïve neck. CONCLUSION: A two-stage delayed-immediate reconstruction of complex mid-face defects can be safely and effectively performed. This protocol takes advantage of advancing CAD/CAM technology, provides an opportunity to evaluate final margins, and avoids recipient vessel dissection and microsurgery in previously operated or irradiated necks.

A Contemporary Framework and Suprastructure Ceramic Design for Posterior Implant Fixed Partial Denture.

Bone and soft tissue deformities in long-standing partial edentulism are commonly treated with implant therapy. The various ceramic restorative systems available and digital technology allow for customization of design and material selection. A substructure design that mimics tooth preparation in a custom zirconia framework with a lithium disilicate suprastructure is presented as an effort to address the functional and esthetic challenges posed by long-standing posterior partial edentulism. The aim is to present several contemporary elements of design to address the functional, esthetic, and maintenance needs.

Adjusting dental ceramics: An in vitro evaluation of the ability of various ceramic polishing kits to mimic glazed dental ceramic surface.

STATEMENT OF PROBLEM: During the insertion appointment, the practitioner is often faced with the need to adjust ceramic surfaces to fit a restoration to the adjacent or opposing dentition and soft tissues. PURPOSE: The purpose of this study was to assess the ceramic surface smoothness achieved with various commercially available ceramic polishing kits on different commonly used ceramic systems. The reliability of the cost of a polishing kit as an indicator of improved surface smoothness was assessed. MATERIAL AND METHODS: A total of 350 ceramic surfaces representing 5 commonly available ceramic systems (IPS Empress Esthetic, IPS e.max Press, Cergo Kiss, Vita PM 9, Imagine PressX) were treated with 5 types of ceramic polishing systems (Cerapreshine, 94006C, Ceramiste, Optrafine, Zenostar) by following the manufacturers' guidelines. The surface roughness was measured with a profilometer (Taylor Hobson; Precision Taylor Hobson Ltd). The effects of ceramic systems and polishing kits of interest on surface roughness were analyzed by 2-way ANOVA, paired t test, and Bonferroni corrected significance level. RESULTS: The ceramic systems and polishing kits statistically affected surface roughness (P<.001).The polishing kit Zenostar on IPS e.max Press created the smoothest ceramic surface. No correlation could be established between the high cost of the polishing kit and low surface roughness. None of the commonly used ceramic polishing kits could create a surface smoother than that of glazed ceramic (P<.001). CONCLUSIONS: The inclusion of a diamond polishing paste step is recommended to improve surface smoothness (P<.001). The cost of ceramic polishing kits is not recommended as a reliable indicator of better performance of ceramic polishing kits (P>.30).

Correction of esthetic and biomechanical outcomes after maxillary anterior single dental implant fracture: a case report.

Rehabilitation of the single anterior tooth in the esthetic region after a dental implant fracture requires management of contributing biomechanical and/or biological etiologic factors. The multidisciplinary treatment of a fractured maxillary anterior single dental implant with a staged, combined surgical and prosthetic approach is discussed. Alleviation of several, but not all, risk factors eliminated the need for replacement of gingiva with pink porcelain and maintained a stable post implant host complex.

Evaluation of fracture resistance in aqueous environment under dynamic loading of lithium disilicate restorative systems for posterior applications. Part 2.

PURPOSE: The goals of part 2 of the study presented here were 1) to assess whether there is a difference in failure mode of different thicknesses (2.0, 1.5, 1.0, and 0.5 mm) of anatomically standardized full contour monolithic lithium disilicate restorations for posterior teeth, and 2) to assess if there is a difference among various crown thicknesses when these restorations are subjected to dynamic load forces common for posterior teeth. MATERIALS AND METHODS: Four groups (n = 10), each with a different thickness of anatomically appropriate all-ceramic crowns, were to be tested as established from the statistical analysis of the preliminary phase. Group 1: 2.0 mm; group 2: 1.5 mm; group 3: 1.0 mm; group 4: 0.5 mm. The specimens were adhesively luted to the corresponding die, and underwent dynamic cyclic loading (380 to 390 N) completely submerged in an aqueous environment until a failure was noted by graphic recording and continuous monitoring. RESULTS: There was a statistically significant difference of the fatigue cycles to failure among four groups (p < 0.001; Kruskal-Wallis test). The mean number of cycles to fail for 2.0 mm specimens was 17 times more than the mean number of cycles to fail for 1.0 mm specimens and 1.5 times more than the mean number of cycles to fail for 1.5 mm specimens. The 0.5 mm specimens failed with one cycle of loading. A qualitative characteristic noted among the 2.0 mm specimens was wear of the area of indenter contact followed by shearing of the material and/or crack propagation. CONCLUSION: Based on the findings of this study, it may be reasonable to consider a crown thickness of 1.5 mm or greater for clinical applications of milled monolithic lithium disilicate crowns for posterior single teeth.

Practice-based evidence from 29-year outcome analysis of management of the edentulous jaw using osseointegrated dental implants.

PURPOSE: The aim of this retrospective study was to summarize practice-based evidence associated with long-term outcomes (>20 years) in the management of edentulous patients. The patient population was managed with implant-supported prostheses, following the original osseointegration protocol, provided over the period from 1983 to 1991 in the group prosthodontics practice at the Mayo Clinic. The data are an example of practice quality assurance monitoring and are used to refine care delivery when needed and to provide information regarding expected outcomes in a shared decision-making interaction with prospective patients. MATERIALS AND METHODS: Two hundred and sixty four patients with at least one edentulous jaw were identified. Of these, 255 completed their care and follow-up at the Mayo Clinic (209 mandible only, 35 maxilla only, 11 mandible and maxilla). Prosthodontic outcomes categorized as anticipated or unanticipated prosthetic and biologic events and the respective interventions required for each were recorded to assess follow-up event dynamics for this care modality. RESULTS: The mean duration of follow-up for 190 of the 255 patients (65 died at a mean follow-up of 12.6 years) was 13.0 years (median 13.6; range 0.3 to 28). At least one prosthetic event was experienced by 148 patients (58%), and 81 (32%) experienced at least one biologic event. Overall, patients experienced 3.8 times more prosthetic events than biologic events. Twenty-four (9%) patients experienced 35 implant failures. Overall survival rates at 20 years were 86% for prostheses, 15% survived free of any event, and 92% experienced survival free of implant failure (95% confidence interval). CONCLUSION: Anticipated and unanticipated prosthetic events occur throughout the life of the hybrid prosthesis. Prosthetic events significantly surpass (four times more) biologic events and occur significantly later in the follow-up. For this patient group, 8.6% (22/255) had implant-supported prostheses remade during follow-up in this patient population. These findings support the recommendation that prosthodontic care for missing teeth be thought of in a "chronic condition" context, recognizing that long-term outcome monitoring to provide realistic care expectations is important for demonstrating care value in oral health promotion.

Practice-based clinical evaluation of ceramic single crowns after at least five years.

STATEMENT OF PROBLEM: Long-term practice-based clinical evaluations of various contemporary ceramic crown restorations from multiple practitioners are limited. PURPOSE: The aims of this study were to evaluate the clinical performance of ceramic single crowns and to identify factors that influence their clinical performance. MATERIAL AND METHODS: Ceramic single crowns that had been placed at the Mayo Clinic and in function since 2005 were identified and included in the study. The restorations were examined clinically, radiographically, and with photographs. Modified United States Public Health Services criteria were used for the clinical evaluation. The ceramic systems evaluated were bilayer and monolayer. RESULTS: Fifty-nine patients (41 women, 18 men) with 226 single teeth and implants restored with single ceramic crowns were identified. The mean duration from insertion date to study examination date was 6.1 years. Thirteen restorations (6%) were replaced at a mean 3.3 years after insertion date (range, 0.1-6.1 years). Estimated replacement-free survival rates (95% confidence interval [CI]; number of teeth/implants still at risk) at 5 years after insertion date were 95.1% (95% CI, 92.2-98.1; 153) and at 10 years were 92.8% (95% CI, 89.1-96.8; 8). The most common reason for replacement was fracture to the core of posterior layered ceramic crowns. The most commonly used luting agent was resin-modified ionomer cement. Most restorations exhibited clinically acceptable marginal integrity, shade, no caries recurrence, and no periapical pathology. CONCLUSIONS: The clinical performance of ceramic single crowns at 5 and 10 years supports their application in all areas of the mouth. With the majority of fractures to the core occurring early in the lifetime of layered ceramic posterior crowns, consideration of other monolithic ceramic systems for posterior crowns is advised.

A tooth-stabilized surgical template for alveolectomy.

The supraeruption of teeth and bone in patients with long-standing partial edentulism often results in compromised interarch distance. A method is presented for the fabrication and predictable use of a tooth-stabilized surgical template for alveolectomy in instances where teeth are present.

Virtual surgical planning for treatment of severe mandibular retrognathia with collapsed occlusion using contemporary surgical and prosthodontic protocols.

PURPOSE: To meet functional and esthetic needs in an older adult for treatment of complex skeletal and dentoalveolar deformities using contemporary surgical and prosthodontic protocols. METHODS: An older adult with dentoalveolar complex and skeletal deformity (mandibular retrognathia) was treated by a combination of virtual planning and current surgical and prosthodontic protocols. Treatment planning steps and sequencing are presented. RESULTS: Skeletal, soft tissue, and dental harmonies were attained without biological or mechanical complications. Definitive oral rehabilitation was completed with a maxillary complete denture and a mandibular metal ceramic fixed implant-retained prosthesis. CONCLUSIONS: A surgical and prosthodontic team approach in combination with technologic advances can predictably optimize esthetic and functional outcomes for patients with complex skeletal and dentoalveolar deformities.

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.

Development of stable peri-implant soft tissue and mentolabial sulcus depth with an implant-retained soft tissue conformer after osteocutaneous flap reconstruction.

Excessive soft tissue bulk, movement, chronic inflammation, and hypertrophy in periimplant areas pose challenges for long-term management of peri-implant soft tissues surrounding osteocutaneous flap reconstructions. A case history report is presented on the predictable establishment of stable peri-implant soft tissue and improved mentolabial sulcus depth in a patient treated for high-grade osteosarcoma of the mandible. Following surgical resection, reconstruction with osteocutaneous fibula free flap, and endosseous implant placement, a combined surgical and prosthetic approach was used through a lip switch vestibuloplasty and an implant-retained soft tissue conformer.

Preference changes of adult outpatients for giving saliva, urine and blood for clinical testing after actual sample collection.

PURPOSE: Patients' preferences of the type of sample collections for clinical testing are currently unknown. The aims of this study were: (1) to assess patients' preferences of three types of samples for clinical testing (saliva, urine and blood) both before and after collection and (2) to assess whether prior experiences with collection of saliva impacted patients responses. METHODS: Adult outpatients underwent collection of one sample each of saliva, urine and blood. Patients' perceptions of comfort, convenience and easiness were assessed in pre-collection and post-collection questionnaires. RESULTS: Post-collection, patients' endorsement of saliva as being the "most comfortable" and "most convenient" significantly declined (pre vs. post, 61.5% vs. 37.5% and 73.1% vs. 42.3%). However, saliva was still endorsed as the "most convenient" post-collection (compared to urine 33.7% and blood 24.0%). Although not statistically significant, the proportion of patients who changed their response in terms of what sample was "easiest to collect at home" was considerably higher in the group with vs. without prior experience giving saliva (54.6% vs. 32.6%, p=0.19 Fisher's exact test). CONCLUSIONS: Overall, saliva remained as the most highly preferred sample to donate despite a decline in patients' preferences of saliva donation after sample collection. The results of the study are promising for future widespread patient acceptance of saliva as a diagnostic fluid.

Evaluation of fracture resistance in aqueous environment of four restorative systems for posterior applications. Part 1.

PURPOSE: The goals of this study were to: (1) establish a range of the performance of four restorative systems for posterior single-tooth crowns under single load to fracture submerged in an aqueous environment, (2) identify restorative system(s) of interest to be examined in the second study phase under sliding contact step-stress fatigue as full-contour anatomically appropriate single posterior tooth restoration(s), (3) establish a range for loading/testing for phase 2. MATERIALS AND METHODS: Forty specimens (n = 10/group) of 2 mm uniform thickness were tested. Group 1: monolithic lithium disilicate IPS e.max Press; group 2: IPS e.max ZirPress, 0.8 mm zirconia core with 1.2 mm pressed veneering porcelain; group 3: IPS e.max ZirPress, 0.4 mm zirconia core with 1.6 mm pressed veneering porcelain; group 4: IPS InLine PoM. Specimens were bonded to a block of polycast acrylic resin on a 30° sloped surface with resin cement. Specimens were axially single loaded to failure while submerged under water. RESULTS: There was a statistically significant difference (p < 0.001) in failure load among the four restorative systems. Lithium disilicate showed a mean failure load similar to mean maximum posterior bite forces (743.1 ± 114.3 N). IPS e.max Zirpress with a 0.4 mm zirconia core exhibited the lowest mean failure load (371.4 ± 123.0 N). CONCLUSION: Fracture resistance of monolithic lithium disilicate in an aqueous environment is promising and requires second phase testing to evaluate the potential of various thicknesses appropriate for posterior single tooth applications. Doubling the IPS e.max Zirpress zirconia core from 0.4 mm to 0.8 mm increased the fracture resistance of this restorative system threefold.

Predoctoral dental students' perceptions and experiences with prosthodontics.

PURPOSE: The aims of this study were to: (1) investigate the perceptions and experiences of predoctoral dental students and advanced standing students on mentorship, exposure to prosthodontics, and future need for the specialty, and (2) establish a baseline of students' perceptions of the impact of prosthodontics on salary, personal and patient quality of life, and the profession of dentistry. MATERIALS AND METHODS: A survey was distributed to 494 predoctoral and advanced standing students at the University of Pennsylvania School of Dental Medicine. Questions focused on the perceptions and experiences with the specialty of prosthodontics. A total of 410 surveys were analyzed using Chi Square tests and univariate and multivariate analysis with statistical software. RESULTS: Response rate was 83%. A positive initial introduction to prosthodontics was reported by 57% of students. Most students had positive experiences with prosthodontic faculty and enjoyed laboratory work and challenging/complex dentistry. A greater need for prosthodontists in the future was perceived by 82% of respondents, with 63% reporting that the future of prosthodontics had been emphasized. Students reported (1) a preclinical course directed by prosthodontists and (2) working in the clinic with prosthodontic faculty (p < 0.006) as having the biggest impact on their introduction to prosthodontics. A desire to pursue training or a career in prosthodontics was reported by 3.4% of the respondents, with 1.7% of them pursuing prosthodontics. Enjoyment of providing care in prosthodontics was the most important factor for those who decided to pursue prosthodontic postgraduate training. When compared to other specialties, prosthodontics ranked low with regards to its impact on salary (7(th) ), personal quality of life (5(th) ), patient quality of life (4(th) ), and strengthening of the dental field (7(th) ). CONCLUSION: Reasons few students are interested in prosthodontics as a career, despite a positive first introduction and high perceived future need for prosthodontists may be attributed to a number of factors. These include insufficient prosthodontically, trained faculty, lack of a mentorship program, lack of an advanced graduate program, a perception of feeling unprepared upon graduation, and misconception of potential income in prosthodontics.

Comparison of two different veneer preparation designs in vital teeth.

OBJECTIVE: To compare the clinical performance of two different veneer preparation designs (overlap and nonoverlap) on anterior veneer restorations in vital teeth in a retrospective clinical study. METHOD AND MATERIALS: In this study, 292 anterior all-ceramic veneer restorations in vital teeth were clinically examined in 74 patients. The preparation designs were categorized by the amount of tooth reduction on the final casts, with 245 in the overlap and 47 nonoverlap group. RESULTS: After a mean ± SD observation time of 124.25 ± 60.61 months, 20 failures occurred. All failures occurred in the overlap design. Restorations with nonoverlap preparation designs showed significantly fewer failures than restorations with overlap preparation design (P = .018, log-rank). CONCLUSION: Based on the findings of this study, whenever feasible, a preparation design without incisal overlap is recommended, especially in vital teeth..

Dental students' perceptions of dental specialties and factors influencing specialty and career choices.

The goals of this study were to 1) evaluate dental students' perceptions of dental specialties, 2) identify factors that play an important role in students' decision to pursue specialty training or career choices, and 3) establish a baseline of students' perceptions of the dental fields with the best future in terms of salary, personal and patient quality of life, and overall impact on the dental profession. Surveys were distributed to 494 students at the University of Pennsylvania School of Dental Medicine. Data were collected from 380 traditional four-year students and thirty advanced standing students. Chi-square tests, multivariate analysis, and logistic regressions were used to determine associations and independent contributions of student demographics to their perceptions of dental specialties and factors influencing specialty training or career choices. Debt was a statistically significant factor (p<0.001) in choosing specialty training or career independent of gender, age, or class year. Enjoyment of providing care in a specialty or field was identified as the single most important factor in choosing a specialty career. Half of the respondents had decided not to specialize. Pursuing postdoctoral general dentistry training and private practice in general dentistry were the most commonly reported plans after completion of dental school. Suggestions are made for ways to inform students about specialty training.