Tamer Abdel-Azim

The influence of digital fabrication options on the accuracy of dental implant-based single units and complete-arch frameworks.

PURPOSE To compare the accuracy and reproducibility of digital versus conventional dental impressions and fabrication techniques for single units and full-arch implant frameworks. MATERIALS AND METHODS A total of 24 samples, divided into four groups, were created using conventional and digital implant impression/fabrication techniques: group 1 (conventional single implant), group 2 (digital single implant), group 3 (conventional complete arch), and group 4 (digital complete arch). All impressions were made at the abutment level. Marginal fit measurements were made using an optical microscope at two points (buccal and lingual) for each sample. Statistical analysis was performed using F and t tests (α = .05). RESULTS For single implants, the conventional impression/fabrication pathway resulted in a mean marginal discrepancy of 24.1 μm compared to 61.43 μm for the digital impression/fabrication pathway. For full-arch frameworks, the conventional impression/fabrication pathway resulted in a mean marginal discrepancy of 135.1 μm compared to 63.14 μm for the digital technique. CONCLUSION The conventional pathway resulted in a smaller marginal discrepancy for single-implant frameworks. In contrast, the digital pathway resulted in a smaller marginal discrepancy for full-arch implant frameworks.

Effect of Implant Divergence on the Accuracy of Definitive Casts Created from Traditional and Digital Implant-Level Impressions: : An In Vitro Comparative Study

PURPOSE The purpose of this research was to compare the accuracy of definitive casts created with digital and conventional methods for implants with internal-octagon connections placed parallel or at different angles (15, 30, or 45 degrees). MATERIALS AND METHODS Four customized epoxy resin master casts were fabricated with two-implant analogs placed in the posterior mandible with different degrees of divergence. For the conventional (control) group, 10 traditional impressions were taken on each master cast with custom trays, open-tray impression copings, and polyvinyl siloxane; definitive stone casts were poured with type IV dental stone. For the digital group, 10 digital impressions were taken on each master cast with two-piece scannable impression copings and an intraoral digital scanner; definitive milled polyurethane casts were fabricated by the manufacturer. All four master casts and 80 control and test casts were scanned and digitized, and the data sets were compared. Any deviations in measurements between the definitive and corresponding master casts were analyzed statistically. RESULTS The amount of divergence between implants did not affect the accuracy of the stone casts created conventionally; however, it significantly affected the accuracy of the milled casts created digitally. A decreasing linear trend in deviations for both distance and angle measurements suggested that the digital technique was more accurate when the implants diverged more. At 0 and 15 degrees of divergence, the digital method resulted in highly significantly less accurate definitive casts. At 30 and 45 degrees of divergence, however, the milled casts showed either no difference or marginal differences with casts created conventionally. CONCLUSION The digital pathway produced less accurate definitive casts than the conventional pathway with the tested two-implant scenarios. To ensure passive fit of definitive prostheses, verification devices and casts may be used when materials are produced digitally.

Complete oral rehabilitation of a patient with hereditary gingival fibromatosis: a clinical report.

Hereditary gingival fibromatosis is a rare disease that has several debilitating oral and psychological manifestations, especially with young children and adolescents. The complexity of the treatment as well as the timing relative to the growth and maturation of the patient present a challenge. Few treatment options have been reported in the literature. This clinical report presents a multidisciplinary approach to treating a young patient with hereditary gingival fibromatosis by using implant-supported prostheses. The treatment steps and its outcome are discussed.

Dental student perception and assessment of their clinical knowledge in educating patients about preventive dentistry

In todays dental school curricula, an increasing amount of time is dedicated to technological advances, and preventive dentistry topics may not be adequately addressed. Freshman (D1) students participated in a new Introduction to Preventive Dentistry course, which consisted of didactic lectures, active learning breakout sessions and case-based studies. The goal of this study was to determine if D1 dental students completing the course had a better knowledge and comfort level with basic preventive dentistry concepts and caries risk assessment than the upcoming graduating senior dental students. Following the completion of the course, D1 students were administered a survey that assessed their comfort level describing preventive dentistry topics to patients. This was immediately followed by an unannounced examination over the same topics. Senior (D4) students, who had not taken a formal course, reported statistically significant higher comfort levels than D1 students. However, the D4s scored significantly lower in all of the examination areas than the D1 students. Higher scores in D1s may have been due to recent exposure to the course material. However, the basic nature of the content-specific questions should be easily answered by novice practitioners educating their patients on oral disease prevention. As the current data shows lower content-specific scores of basic preventive dentistry knowledge amongst graduating D4 students, this may indicate a need for more guidance and education of students during the patient care. This study showed that implementation of a formalised course for D1 students can successfully ameliorate deficiencies in knowledge of preventive dentistry topics.

Influence of oscillating and rotary cutting instruments with electric and turbine handpieces on tooth preparation surfaces

STATEMENT OF THE PROBLEM Rotary and nonrotary cutting instruments are used to produce specific characteristics on the axial and marginal surfaces of teeth being prepared for fixed restorations. Oscillating instruments have been suggested for tooth preparation, but no comparative surface roughness data are available. PURPOSE To compare the surface roughness of simulated tooth preparations produced by oscillating instruments versus rotary cutting instruments with turbine and electric handpieces. MATERIAL AND METHODS Different grit rotary cutting instruments were used to prepare Macor specimens (n=36) with 2 handpieces. The surface roughness obtained with rotary cutting instruments was compared with that produced by oscillating cutting instruments. The instruments used were as follows: coarse, then fine-grit rotary cutting instruments with a turbine (group CFT) or an electric handpiece (group CFE); coarse, then medium-grit rotary cutting instruments with a turbine (group CMT) or an electric handpiece (group CME); coarse-grit rotary cutting instruments with a turbine handpiece and oscillating instruments at a low-power (group CSL) or high-power setting (group CSH). A custom testing apparatus was used to test all instruments. The average roughness was measured for each specimen with a 3-dimensional optical surface profiler and compared with 1-way ANOVA and the Tukey honestly significant difference post hoc test for multiple comparisons (α=.05). RESULTS Oscillating cutting instruments produced surface roughness values similar to those produced by similar grit rotary cutting instruments with a turbine handpiece. The electric handpiece produced smoother surfaces than the turbine regardless of rotary cutting instrument grit. CONCLUSION Rotary cutting instruments with electric handpieces produced the smoothest surface, whereas the same instruments used with a turbine and oscillating instruments achieved similar surface roughness.

Fabrication of a fixed multipurpose template retained by existing dental implants

This report describes the use of a multipurpose template stabilized with existing implants to provide accurate information for immediate implant placement, to facilitate impression making, and to record maxillomandibular relationships for the fabrication of an interim immediate implant-supported fixed prosthesis.

A direct technique to fabricate an intraoral shield for unilateral head and neck radiation

A radiation oncologist may ask the prosthodontist to fabricate an intraoral shield when ipsilateral fields are used for patients with head and neck cancer. A technique for its fabrication is described that can be accomplished with materials and equipment that are readily available in the dental office. Baseplate wax is used intraorally to fabricate a pattern, which is duplicated with irreversible hydrocolloid material. Autopolymerizing acrylic resin is then used to make the shield. This simple technique can be completed in a single visit.

Oral rehabilitation of an edentulous patient using two-segment le fort I repositioning and implant-supported fixed prostheses.

Anteroposterior (AP) deficiencies present a restorative treatment challenge. Complex, multidisciplinary planning is necessary for the success of the treatment. This clinical report describes an approach to managing a complex complete oral rehabilitation of an edentulous patient with skeletal transverse and AP deficiencies with a history of facial trauma to the left zygomaticomaxillary complex. This was further complicated by a hopeless remaining dentition and pneumatization of the maxillary sinuses. Treatment included initial bony augmentation of the vertically and horizontally deficient maxilla, dental implant placement, provisional restoration in a Class III malocclusion with bilateral posterior crossbite, and Le Fort I osteotomy with transverse widening and advancement to correct the skeletal deficiency. Definitive restoration was accomplished with implant-supported fixed prostheses that provided ideal facial balance and occlusion.