Philip S. Baker

Fabrication of a definitive obturator from a 3D cast with a chairside digital scanner for a patient with severe gag reflex: A clinical report

Patient gagging is a common problem during dental procedures such as maxillary impression making. This clinical report describes the use of a chairside intraoral scanner for a patient with a hypersensitive gag reflex. The technique proved to be a more comfortable alternative for the patient and an accurate method for the clinician to capture both hard and soft tissue detail for the fabrication of a definitive obturator.

A case report of subpontic osseous hyperplasia in the maxillary arch.

Subpontic osseous hyperplasia has been portrayed in both the historical and the current literature as occurring exclusively in the mandibular posterior region. This article presents the clinical, radiologic, and microscopic documentation of subpontic osseous hyperplasia occurring in the maxillary first molar region.

Accuracy and precision of as-received implant torque wrenches

STATEMENT OF PROBLEM Previous implant torque evaluation did not determine if the target value fell within a confidence interval for the population mean of the test groups, disallowing determination of whether a specific type of wrench met a standardized goal value. PURPOSE The purpose of this study was to measure both the accuracy and precision of 2 different configurations (spring style and peak break) of as-received implant torque wrenches and compare the measured values to manufacturer-stated values. MATERIAL AND METHODS Ten wrenches from 4 manufacturers, representing a variety of torque-limiting mechanisms and specificity of use (with either a specific brand or universally with any brand of implant product). Drivers were placed into the wrench, and tightening torque was applied to reach predetermined values using a NIST-calibrated digital torque wrench. Five replications of measurement were made for each wrench and averaged to provide a single value from that instrument. The target torque value for each wrench brand was compared to the 95% confidence interval for the true population mean of measured values to see if it fell within the measured range. RESULTS Only 1 wrench brand (Nobel Biocare) demonstrated the target torque value falling within the 95% confidence interval for the true population mean. For others, the targeted torque value fell above the 95% confidence interval (Straumann and Imtec) or below (Salvin Torq). CONCLUSIONS Neither type of torque-limiting mechanism nor designation of a wrench to be used as a dedicated brand-only product or to be used as a universal product on many brands affected the ability of a wrench to deliver torque values where the true population mean included the target torque level.

Water immersion procedure for making light-cured custom trays with wax spacers

This article describes a modified light-curing method that minimizes wax spacer heating and distortion. In addition, this method eliminates the need for tinfoil adaptation or use of a coating to make an air barrier in the fabrication of light-cured custom trays for removable prosthodontics.

Relationship of denture cast measurements to width of maxillary anterior teeth

STATEMENT OF PROBLEM When making complete dentures, clinicians may have difficulty with selection of properly sized denture teeth. PURPOSE The purpose of this study was to determine if there are specific measurements made on an edentulous cast that could be useful to clinicians for selection of proper maxillary anterior denture tooth width. MATERIAL AND METHODS Following Institutional Review Board approval, measurements were made on 50 maxillary and mandibular sets of complete denture casts and their marked and contoured occlusion rims and record bases consecutively submitted to a dental laboratory. The following 6 measurements were recorded for each set of casts: left mid-maxillary to right mid-maxillary, representing the distance between the respective residual ridge crest points adjacent to each canine eminence; left retromolar pad to right retromolar pad; incisive papilla to left hamular notch; incisive papilla to right hamular notch; left hamular notch to right hamular notch; and incisive papilla to vibrating line. These measurements were statistically compared with the control, the canine-to-canine distance as marked on the contoured maxillary occlusion rim to indicate the relaxed commissures. The casts were also classified as small, medium or large based upon the tooth width specified by the commercial mold guide for their respective canine-to-canine control measurement. The estimation bias was determined for each of the 6 measurements, and for those measurements for which the bias was significantly different from zero, a bias-correction was applied. St. Laurents coefficient was used to describe the agreement between each (bias-corrected) measurement and the canine-to-canine control. A commercial guide was used to determine the accuracy of each of the 6 bias-corrected measurements in classifying denture teeth width as small, medium or large as compared to the same classification using the canine-to-canine control. RESULTS The bias-corrected measurement from the left hamular notch mark to the right hamular notch mark, obtained by adding 10 mm, exhibited the greatest degree of agreement with the control. This measurement was also the only one of the 6 that correctly classified more than 50% of both the medium and large casts. None of the 6 measurements classified more than 30% of the small casts correctly. CONCLUSIONS Of the 6 measurements considered here, the bias-corrected measurement from left hamular notch mark to right hamular notch mark was preferred for selecting denture teeth width.

Method for immediate fabrication of an occlusal device

This article describes a method of in-office fabrication of an occlusal device for treatment of bruxism patients seeking a less costly alternative to laboratory-processed splints. This technique eliminates the need for mounted casts and the expense and delay associated with commercial laboratory involvement. It also minimizes patient and operator exposure to acrylic resin monomer and high temperatures associated with its polymerization reaction by use of a light-polymerized blue urethane dimethacrylate resin.

In vitro mechanical analysis of complete-arch mandibular implant-supported fixed prostheses abutment screws after cyclic loading

STATEMENT OF PROBLEM Clinicians question when to evaluate for worn or loose implant-supported retainer screws to prevent possible clinical complications. PURPOSE The purpose of this study was to compare differences among initial and postdynamically loaded detorque values and identify physical structural changes of prosthetic retaining screws in a simulated implant-supported mandibular complete fixed prosthesis. MATERIAL AND METHODS Nine groups and nonloaded controls comprising a 5-implant-supported, milled titanium framework were fabricated and assembled (screw torque 35 Ncm). Dynamic loading (20 to 220 N) was applied to simulate 2 years of oral function. After testing, screw detorque values were measured (ΔT, initial-detorque value). A scanning electron microscopic analysis of screw threads was used to assess physical changes. Data were analyzed by 2-way ANOVA to determine the influence of loading and implant position on ΔT (α=.05). RESULTS ΔT values of loaded and nonloaded groups were compared separately at each implant position and showed a significant difference only for the implant in the central position (P=.002). All positions were compared in terms of ΔT values separately for loaded and nonloaded conditions. A significantly higher ΔT was found in 1 cantilever area of the loaded group, whereas a significantly lower ΔT value was found in the central position in the nonloaded group. No statistically significant differences were found in physical changes between loading and nonloading or among implant positions. CONCLUSIONS When delivering a multiimplant supported prosthesis, the application of dynamic loading and the sequence in which implant screws are tightened could influence the subsequent detorque value of a screw; they have no effect on the physical appearance of screws after extended function.

Method for fabrication of a cast mounting device with interchangeable occlusal templates

A definitive impression technique using both impression wax and vinyl polysiloxane impression material for displaceable mandibular residual ridges is described. Consideration has been given to the choice of impression materials as well as to the design of the impression tray to minimize the amount of pressure exerted onto the displaceable regions of the residual ridges during the impression-making procedure. REFERENCES

Digital design and 3D printing of an implant-supported prosthetic stent for protecting complete arch soft tissue grafts around dental implants: A dental technique

&NA; A method for digital fabrication of an implant‐supported soft tissue graft stent to protect, shape, and ensure intimate adaptation of the complete arch graft to the periosteum surrounding dental implants is described. To fabricate the stent, an extraoral scanner was used to convert the implant cast into digital data. Dental design software was then used to fabricate the stent, which is produced by 3‐dimensional (3D) printing. Due to the lack of long‐term biocompatible 3D printing material, the stent was duplicated in bisacryl resin. The patient reported more comfort and stability with the implant‐supported stent than the conventional stent received following a previous debulking surgical procedure.

Digital design of a surgical guide for placement of definitive implants before orthodontic treatment.

Interdisciplinary treatment planning is an essential part of orthodontic therapy for patients with partial edentulism, especially when dental implants are to serve initially as anchorage and ultimately as prosthetic abutments for the definitive fixed restoration. A technique is presented for designing and fabricating a computed tomography-based surgical guide to place definitive implants before orthodontic therapy. First, the diagnostic cast and the orthodontic tooth arrangement and diagnostic waxing cast are scanned with a 3-dimensional optical scanner. Three-dimensional renderings of these scans are then merged and superimposed onto the cone beam computed tomography (CBCT) image with implant planning software to develop definitive implant positions. A custom surgical guide is fabricated from these data.