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The use of all-ceramic crowns offers the potential for improved aesthetic results compared to conventional ceramo-metal crowns. Silica/glass-based all-ceramic crowns are more translucent than alumina- or zirconia-based crowns and therefore have better optical properties. However, they are mechanically weaker and need to be used in conjunction with resin bonding cements. Both these aspects lead to increased clinical and technical demands and as such there are strict guidelines regarding tooth preparation and bonding procedure that need to be followed when using silica/glass-based all-ceramic crowns. The following article describes these preparation, impression and bonding guidelines with the aid of a case presentation.

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BACKGROUND: This study reports the short- and long-term results for a prospective rectal cancer management program using laparoscopic radical transanal abdominal transanal proctosigmoidectomy with coloanal anastomosis (TATA) after neoadjuvant therapy. METHODS: A prospective database included 102 rectal cancer patients treated with laparoscopic TATA from 1998 to 2008. Patients with distant metastasis at presentation, patients with a tumor more than 3 cm from the anorectal ring, and patients not undergoing neoadjuvant therapy were excluded, leaving 79 patients (54 men and 25 women) with a mean age of 59.2 years (range, 22-85 years) for this study. 13 patients completed neoadjuvant therapy before the original evaluation, and they are excluded from the report of initial clinical assessment. Before treatment, 50 patients were staged as T3 and 16 patients as T2. The mean level in the rectum superior to the anorectal ring was 1.2 cm (range, -0.5 to 3 cm). In terms of fixity, 31 of the tumors were mobile, 27 were tethered, and 8 showed early fixation. Ulceration was absent in 8 cases, minimal in 12 cases, superficial in 7 cases, moderate in 22 cases, and deep in 17 cases. The mean pretreatment tumor size tumor was 4.8 cm (range, 1.5-12 cm). The median external beam radiation was 5,400 cGy (range, 3,000-8,040 cGy), and 77 patients underwent chemotherapy. RESULTS: The mean follow-up period was 34.2 months (range, 1.9-113.9 months). There were no perioperative mortalities. The conversion rate was 2.5%, and the mean largest incision length was 4.3 cm (range, 1.2-21 cm). For 84% of the patients, the incision was less than 6.0 cm, and 46% of the patients had no abdominal incision for delivery of the specimen. The mean estimated blood loss was 367 ml (range, 75-2,200 ml). All the patients had a temporary diverting stoma. The major morbidity rate was 11%, and the minor morbidity rate was 19%. The major complications included four full-thickness rectal prolapses with repair, one ischemic neorectum with successful reanastomosis, two bowel obstructions, and two failed anastomoses requiring stoma. The ypT stages included 22 complete responses, 12 cases of ypT1, 22 cases of ypT2, 23 cases of ypT3; 65 cases of ypN0, and 14 cases of ypN + (T3 = 7, T2 = 4, T1 = 3). The local recurrence rate was 2.5% (2/79), and the distant metastases rate was 10.1% (8/79). The KM5YAS rate was 97%. Overall, 90% of the patients lived without a stoma. Neorectal loss was due to positive margins or recurrence and was followed by abdominoperineal resection in three cases and ischemia in two cases. The condition of two patients was not reversed due to comorbidities, and one patient had a stoma secondary to bowel obstruction. CONCLUSION: The study results indicate excellent local recurrence (2.7%) and 5-year survival rates without the need for permanent colostomy in patients with cancers in the distal one-third of the rectum. Laparoscopic total mesorectal excision (TME) with the TATA approach is safe and can be performed laparoscopically. Multi-institutional studies are required to establish the reproducibility of this promising approach.

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We evaluated the biocompatibility of an injectable gelling polymeric device for the controlled release of gentamicin sulfate in the treatment of invasive bacterial infections in bone of male Wister rats. The biodegradable delivery carrier, poly(sebacic-co-ricinoleic-ester-anhydride), designated as p(SA:RA), was injected, with and without gentamicin, into the tibial canal. Rats were killed 3 weeks later. The tibiae were processed histologically, leaving the injectable polymer in situ. The local tissue reaction to the polymer with or without antibiotic consisted mainly of mild reactive fibroplasia/fibrosis and mild to moderate increased reactive bone formation. At this stage, no evidence for any active inflammatory response to the polymer was seen. Thus, the injection of p(SA:RA) was well tolerated and did not induce any signs of a progressive inflammatory reaction.

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The full coverage, all-ceramic restoration of an anterior tooth is a challenging clinical situation for which a variety of all-ceramic systems and cements are available. The decision making process involves the consideration of a number of factors such as underlying substrate colour, tooth preparation geometry, margin location and cementation system. This article discusses the rationale behind these factors and presents a logical and scientific based sequence for the decision making process. A clinical case is presented to demonstrate the requirements and materials necessary for the optimal resin bonded anterior crown.

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There are certain advantages to restoring a complete arch simultaneously, however, attempting to do this requires that the dentist maintains control during all stages of treatment. Maintaining control alleviates the preassure of time, which in turn allows for precision to be obtained at all clinical and laboratory stages. Two potential areas where control may be diminished or lost are: i) the construction and utilisation of temporary restorations that are biomechanically sound, durable, aesthetic and make a significant contribution to the final result; and ii) obtaining a master cast with accurate dies of all the tooth preparations. This article discusses a logical and practical approach to complete arch restorations and describe the advantages of moving from initial temporary restorations through laboratory processed, provisional restorations and then on to the final restorations. A practical approach for obtaining a single cast with acurate dies of all the tooth preparations is also discussed.

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Within the framework of the efforts to find non-invasive treatment methods for severe periodontitis, a topical gel was developed by an Israeli research group. The aim of the current study is to present clinical observations and X-ray measurements of alveolar bone changes following an 8 week, self-care periodontal treatment in two groups of patients with severe periodontitis. All 31 patients who participated in the study showed an improvement of the periodontal condition as expressed in all the indexes examined. The observation findings testify to the fact that through self-care using a topical gel, significant results were achieved: decrease in probing depth, decrease in bleeding, significant improvement in teeth mobility and in level of the alveolar bone height and its density. These clinical findings raise interesting research questions and hint at the potential for regeneration of supportive periodontal tissues in cases of severe periodontitis, currently achieved only through surgical means. In order to obtain more accurate data regarding the treatment potential of this gel, it is important to conduct additional controlled clinical trials on different populations and also to try and determine how it works.

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The dental literature is replete with information on various implant surgical template designs and imaging techniques for presurgical assessment of dental implant sites. Seldom are these two aspects combined in a practical and effective manner to fabricate a guide for precise implant placement. Unless detailed, three-dimensional images of the underlying bone are obtained, the use of a template is ineffective. This article describes a radiographic/surgical template that utilizes a series of telescoping metal tubes as radiographic markers and as implant drill guides.

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Various disorders related to the masticatory muscles or to the temporomandibular joints may be encountered in a restorative dental practice. Most of them can be managed by the restorative dentist whose primary interest may not lie in the area of temporomandibular disorders. The term temporomandibular disorders is used in this discussion to denote the group of diseases of the masticatory system that involves primarily the temporomandibular joints, the masticatory muscles, and the occlusion of the teeth. The learning objective of this article is to describe temporomandibular disorders encountered in general practice. Managing these disorders in the general practice of restorative dentistry is not difficult and adds to the comfort of the patient and possibly to the success of the restorations.

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This article describes dual-arch impression technique (DAIT) used with alginate impression material, to obtain diagnostic models of the prepared and opposing teeth. Using this quick and simple procedure, tooth preparation, abutment parallelism, and occlusal clearance can all be critically assessed outside the mouth. Any problem areas can be corrected at a subsequent appointment, prior to taking the final impression.

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Previous studies have shown that due to poor adhesion between bonding resins and stainless steel orthodontic brackets, this interface remains a weak link in clinical orthodontic practice. A paste-like substance, Sebond, has been developed in order to strengthen the weak link between metal and resin. The present study was carried out to determine the effect on the shear bond strength, of pretreating the bracket base with Sebond. Two composite resins, Concise Orthodontic Bonding System and Nimetic-Grip were tested, using 40 orthodontic brackets for each resin; 20 brackets were pretreated with Sebond and the remaining 20 acted as controls. Of the Sebond brackets 10 were sandblasted prior to Sebond application. The bonded brackets were stored in water at 37 degrees C for 14 days after which they were tested to failure in the shear mode. Analysis of the results, using a general linear models analysis, showed that pretreating the brackets with Sebond significantly reduced shear bond strength (P < 0.001).

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