Acrylic Template Research Articles

A modified technique for retention of orbital prosthesis

An orbital defect (congenital or acquired) causes severe facial asymmetry and disfigurement, which results in psychological and social disturbances to the patient. It becomes a challenging task for a maxillofacial prosthodontist to fabricate a prosthesis that replicates the healthy side of the face. Success of the prosthesis depends primarily on satisfactory retention of the same. This clinical report illustrates rehabilitation of a patient with an orbital defect by fabricating a hollow orbital prosthesis, utilizing anatomical undercuts for retention using an acrylic resin template relined by a resilient denture liner.

TMJ total joint replacement with the TMJ concepts system; use of an acrylic glenoid fossa template in ankylosis cases

TMJ total joint replacement with the TMJ concepts system; use of an acrylic glenoid fossa template in ankylosis cases

Effect of connective tissue graft orientation on the root coverage outcomes of coronally advanced flap

The aim of the present study was the evaluation of the effect of connective tissue graft orientation on clinical outcome of root coverage procedure when applied in conjunction with coronally advanced flap. Sixteen similar bilateral recession defects--Miller's class I and II--in eight patients were treated using coronally advanced flap and connective tissue graft harvested from the palate. The defects in each patient were randomly allocated to P-teeth or P-flap groups with the periosteum contacting the tooth surface or the flap, respectively. After initial scaling and root planing, acrylic templates of the treatment sites were generated. Recession depth (RD), recession width (RW), gingival sulcular depth, clinical attachment level, length of keratinized tissue, papilla width, and percentage of root coverage were measured at baseline, 1 and 3 months postoperatively. Wilcoxon and Mann-Whitney U tests were used for analyzing the data. The reduction in RD averaged 3.68 mm in P-teeth and 3.25 mm in P-flap. RW decreased 2.68 and 2.6 mm in P-teeth and P-flap, respectively. Keratinized tissue increased an average of 1.25 mm in P-teeth and 1.31 mm in P-flap. Clinical attachment gain equaled 3.87 mm for P-teeth and 3.32 mm for P-flap. All variables exhibited significant improvement compared to baseline (P < 0.0001), but between-group differences were negligible (P > 0.05). It could be concluded that while the application of connective tissue graft with coronally advanced flap is efficient for coverage of Miller's class I and II gingival recession defects, the short-term clinical outcome of this surgical method is not affected by orientation of connective tissue graft.

Influence of thermal and mechanical cycling on the flexural strength of ceramics with titanium or gold alloy frameworks

Objectives The aim of this study was to evaluate the effect of thermal and mechanical cycling alone or in combination, on the flexural strength of ceramic and metallic frameworks cast in gold alloy or titanium. Methods Metallic frameworks (25 mm × 3 mm × 0.5 mm) ( N = 96) cast in gold alloy or commercial pure titanium (Ti cp) were obtained using acrylic templates. They were airborne particle-abraded with 150 μm aluminum oxide at the central area of the frameworks (8 mm × 3 mm). Bonding agent and opaque were applied on the particle-abraded surfaces and the corresponding ceramic for each metal was fired onto them. The thickness of the ceramic layer was standardized by positioning the frameworks in a metallic template (height: 1 mm). The specimens from each ceramic–metal combination ( N = 96, n = 12 per group) were randomly assigned into four experimental fatigue conditions, namely water storage at 37 °C for 24 h (control group), thermal cycling (3000 cycles, between 4 and 55 °C, dwell time: 10 s), mechanical cycling (20,000 cycles under 10 N load, immersion in distilled water at 37 °C) and, thermal and mechanical cycling. A flexural strength test was performed in a universal testing machine (crosshead speed: 1.5 mm/min). Data were statistically analyzed using two-way ANOVA and Tukey's test ( α = 0.05). Results The mean flexural strength values for the ceramic–gold alloy combination (55 ± 7.2 MPa) were significantly higher than those of the ceramic–Ti cp combination (32 ± 6.7 MPa) regardless of the fatigue conditions performed ( p < 0.05). Mechanical and thermo-mechanical fatigue decreased the flexural strength results significantly for both ceramic–gold alloy (52 ± 6.6 and 53 ± 5.6 MPa, respectively) and ceramic–Ti cp combinations (29 ± 6.8 and 29 ± 6.8 MPa, respectively) compared to the control group (58 ± 7.8 and 39 ± 5.1 MPa, for gold and Ti cp, respectively) ( p < 0.05) (Tukey's test). While ceramic–Ti cp combinations failed adhesively at the metal–opaque interface, gold alloy frameworks exhibited a residue of ceramic material on the surface in all experimental groups. Significance Mechanical and thermo-mechanical fatigue conditions decreased the flexural strength values for both ceramic–gold alloy and ceramic–Ti cp combinations with the results being significantly lower for the latter in all experimental conditions.

Advanced Surgical Guidance Technology: A Review

To maximize the outcome of implant placement, the use of advanced radiographic procedures such as computerized tomography, along with fabrication of surgical guides, has been advocated to inform surgeons of ideal implant location. More recently, simulation computer software has been introduced to view radiographic images and test potential implant locations. Yet, surgical guides are processed based on ideal tooth position, with little consideration for underlying anatomical limitations, which creates a disconnection between diagnostic planning and surgical restrictions. In response to this "missing link," computer-assisted design and computer-assisted manufacturing, as well as real-time surgical navigation were recently developed to obtain fully integrated surgical and prosthetic planning. Today, there are several technologies available, but, to our knowledge, a systematic assessment of surgical guidance has not yet been performed. Therefore, the aims of this review are to introduce advanced radiographic and software modalities, and present a detailed assessment of computer-assisted design and computer-assisted manufacturing methods and surgical navigation.

Penile brachytherapy: Results for 49 patients

To report results for 49 men with squamous cell carcinoma (SCC) of the penis treated with primary penile interstitial brachytherapy at one of two institutions: the Ottawa Regional Cancer Center, Ottawa, and the Princess Margaret Hospital, Toronto, Ontario, Canada. From September 1989 to September 2003, 49 men (mean age, 58 years; range, 22-93 years) had brachytherapy for penile SCC. Fifty-one percent of tumors were T1, 33% T2, and 8% T3; 4% were in situ and 4% Tx. Grade was well differentiated in 31%, moderate in 45%, and poor in 2%; grade was unspecified for 20%. One tumor was verrucous. All tumors in Toronto had pulsed dose rate (PDR) brachytherapy (n = 23), whereas those in Ottawa had either Iridium wire (n = 22) or seeds (n = 4). Four patients had a single plane implant with a plastic tube technique, and all others had a volume implant with predrilled acrylic templates and two or three parallel planes of needles (median, six needles). Mean needle spacing was 13.5 mm (range, 10-18 mm), mean dose rate was 65 cGy/h (range, 33-160 cGy/h), and mean duration was 98.8 h (range, 36-188 h). Dose rates for PDR brachytherapy were 50-61.2 cGy/h, with no correction in total dose, which was 60 Gy in all cases. Median follow-up was 33.4 months (range, 4-140 months). At 5 years, actuarial overall survival was 78.3% and cause-specific survival 90.0%. Four men died of penile cancer, and 6 died of other causes with no evidence of recurrence. The cumulative incidence rate for never having experienced any type of failure at 5 years was 64.4% and for local failure was 85.3%. All 5 patients with local failure were successfully salvaged by surgery; 2 other men required penectomy for necrosis. The soft tissue necrosis rate was 16% and the urethral stenosis rate 12%. Of 8 men with regional failure, 5 were salvaged by lymph node dissection with or without external radiation. All 4 men with distant failure died of disease. Of 49 men, 42 had an intact and tumor-free penis at last follow-up or death. The actuarial penile preservation rate at 5 years was 86.5%. Brachytherapy is an effective treatment for T1, T2, and selected T3 SCC of the penis. Close follow-up is mandatory because local failures and many regional failures can be salvaged by surgery.

An Image‐Guided System Based on Custom Templates: Case Reports

With the use of computer-assisted surgery and other modern imaging technologies, the surgeon's procedures have been modified. The purpose of these case reports is to show the clinical predictability of dental implant placement using an image-guided system. An acrylic template is made on the patient model. After computed tomographic examination, a treatment plan is established with appropriate software. To fabricate the surgical template, it is necessary to use a dedicated drilling machine. The first osteotomy is achieved through the template with a 2 mm twist drill. The template is then removed, and the osteotomy is completed, followed by implant placement with standard clinical procedures. An excellent predictability was observed between the planned implants and those placed in the two maxillary cases presented: a full upper screw-retained bridge and two single units. This new technology improves the treatment outcome and optimizes the surgical procedure.

A simple and reliable method to simulate multileaf-plans

To combine conformity of the irradiation with time effectiveness during treatment, the use of multileaf collimators has become more and more common. However, the simulation of the leaf positions is rather difficult compared with metal blocks. We developed a new method, utilizing an acrylic template in which the contour produced by the leaves is machined in the form of a 1 mm groove by a computerized numerically controlled milling machine. This template is then inserted into a mount attached to the simulator. The main advantages are the errorfree, direct communication from the therapy planning system to the milling machine via a network, the possibility to transfer the contour to the skin, and the documentation on the simulation film. The use of templates is reliable and, e.g. the costs of the materials are lower than for block simulation.

Tibial tubercle-medial malleolar distance in determining tibial nail length.

To assess the accuracy of a previously undescribed method of determining tibial nail length based on anatomic landmarks. Cadaveric study. Four methods of tibial nail length determination were compared. Nail lengths for each of fourteen cadaveric lower extremities were determined using full-length scanograms, spotograms, acrylic template overlays, and the distance between the tibial tubercle and the medial malleolus (TMD). Each tibia was then nailed. The accuracy of each method was then evaluated. The full-length scanogram method resulted in incorrect nail lengths in eleven of fourteen (79 percent) cases. Six of fourteen (43 percent) incorrect nail lengths resulted from the use of spotograms. All measurements made with the Template technique yielded nails that were too short (100 percent). The TMD method rendered four of fourteen (29 percent) nails of incorrect size. The tibial tubercle-medial distance (TMD) proved an easy, inexpensive, and accurate method of preoperative nail assessment.

Fabrication and use of a surgical template for placing implants to retain an auricular prosthesis

A procedure is described for the fabrication of a 3-dimensional surgical template to guide the placement of implants to retain an auricular prosthesis. This procedure requires a diagnostic wax pattern that is checked while on the patient to ensure it is positioned correctly and is also the correct size. The wax pattern is processed into a clear, methyl methacrylate resin, 3-dimensional surgical template. The most effective type of surgical template for planning implant placement is a 3-dimensional acrylic template that closely resembles the final prosthesis. This template will direct the implant placement where the retentive elements are most easily concealed, under the thickest areas of the prosthesis, which are the antihelix and antitragus. This location allows the best esthetic and functional results. An additional advantage of this technique is that it allows the retrieval of the diagnostic wax pattern of the auricle so that it can be used to fabricate the definitive prosthesis. (J Prosthet Dent 1999;81:228-33.)

A technical note on placement of the mandibular staple bone plate

The technical modifications suggested for placement of the mandibular staple bone plate include the positioning of the acrylic template at the onset of the procedure and the insertion of an excess amount of Steri-drape intraorally at the time the patient is draped. The assistant can then manipulate the acrylic template and director rods from a sterile field. The perception of when the drill bit has completely traversed the alveolar bone is improved by relieving the acrylic template at the site at which the transosteal pins penetrate into the oral cavity. The advantages of these modifications are threefold: the entire surgical team remains sterile, the risk of contaminating the surgical field is reduced, and the procedure is rendered more time-efficient.

Combination of external beam irradiation and multiple-site perineal applicator (MUPIT) for treatment of locally advanced or recurrent prostatic, anorectal, and gynecologic malignancies

We have devised a single after-loading applicator, the Martinez Universal Perineal Interstitial Template (MUPIT), which has been used in combination with external beam irradiation to treat 104 patients with either locally advanced or recurrent malignancies of the cervix, vagina, female urethra, prostate, or anorectal region. Twenty-six patients treated for prostate cancer are excluded because of their short follow-up. Local failure developed in 13 of the 78 remaining patients (16.6%)—major complications developed in 4 patients (5.1%). Follow-up has been 1 year to 71 2 years; 60 78 patients have been followed for more than 2 years. All local recurrences and complications occurred before 18 months. The device consists of two acrylic cylinders, an acrylic template with an array of holes that serve as guides for trocars, and a cover plate. In use, the cylinders are placed in the vagina and/or rectum or both and then fastened to the template so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Appropriate computer programs have been developed to calculate the dose from these implants. The advantages of the system are (a) greater control of the placement of sources relative to the tumor volume and critical structures, as a result of the fixed geometry provided by the template and cylinders, and (b) improved dose-rate distributions obtained by means of computerized optimization of the source placement and strength during the planning phase. We conclude that the local control rate (83.4%) with low morbidity (5.1%) achieved with the combination of external beam irradiation and MUPIT applicator in these patients with locally advanced malignancies represents an improvement over previous published results with other applicators.

A multiple-site perineal applicator (MUPIT) for treatment of prostatic, anorectal, and gynecologic malignancies.

Recently, transperineal interstitial-intracavitary applicators have been used to treat locally limited and advanced perineal and gynecologic malignancies. We have developed a single afterloading applicator, referred to as the "MUPIT" (Martinez Universal Perineal Interstitial Template), which with its prototypes has been utilized to treat 78 patients with malignancies of the cervix, vagina, female urethra, perineum, prostate, and anorectal region. The device basically consists of two acrylic cylinders, an acrylic template with a predrilled array of holes that serve as guides for trocars, and a cover plate. Some of the guide holes on the template are angled outward to permit a wide lateral coverage without danger of striking the ischium. The cylinders have an axial hole large enough to pass a central tandem or a suction tube for the drainage of secretions. Thus, the device allows for the interstitial placement of 192Ir ribbons as well as the intracavitary placement of either 137Cs tubes or 192Ir ribbons. In use, the cylinders are placed in the vagina and rectum and then fastened to the template, so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Hollow, closed-end, stainless steel trocars are then inserted through the guide holes that produce optimal coverage of the treatment volume. Appropriate computer programs also have been developed on a minicomputer for the corresponding dose-rate computations. These programs run with sufficient speed that they may be used for both the planning of the source placement beforehand and the computation of the actual dose-rate distribution obtained. The advantages of the system are (1) greater control of the placement of sources relative to the tumor volume and critical structures owing to the fixed geometry provided by the template and cylinders, and (2) improved dose-rate distributions obtained by means of computer-assisted optimization of the source placement and strength during the planning phase.

An improved microslide immunodiffusion technique

The microslide immunodiffusion technique of Wadsworth was modified to make it compatible with currently available laboratory equipment and to increase its efficiency, reliability, and precision. The wells in the acrylic template were enlarged to 2.0 mm to allow use of the Micro/Pettor C pipetting system for rapid, precise, uniform, and bubble-free filling of the wells. This technique has been used successfully for several immunological tests, particularly for the detection and assay of Clostridium perfringens enterotoxin and antienterotoxin.

The within-patient reliability of a three-dimensional cephalometric implant technique

Two coned X-ray beams discharged simultaneously from separate sources produced two images of the face and maxillary and mandibular implants on a single 10 × 12-in. film. Triangulation from measurements of the double images of the three implants in each jaw allowed calculation of x, y and z coordinates and a resulting fixed base to examine treatment changes with the aid of computer programming. Sixteen patients, previously implanted with three tantalum implants in the mandible and maxilla, were fitted with custom-cemented acrylic templates on central incisors with a 0.5 mm dia amalgam markers. Two films were taken as well as one 90 days later with re-cemented markers in place. The standard error for this technique was calculated as 0.255 mm for the maxilla and 0.222 mm for the mandible. Confidence limits to detect possible implant movement were computed.