Antenatal sonographic diagnosis of club foot with particular attention to the implications and outcomes of isolated club foot

OBJECTIVE: This study assessed the clinical performance of dentin-bonded crowns, in which ceramic crowns are bonded to underlying dentin with a resin composite-based luting material and a dentin bonding agent. METHOD AND MATERIALS: Twenty-five patients who had received such restorations more than 1 year previously were recalled for evaluation of their crowns. RESULTS: Sixty dentin-bonded complete-coverage restorations were assessed. Forty-one of the crowns had been placed on incisor teeth. The mean time since placement of the restorations was 2.43 years. Fifty-seven of the 60 restorations were intact. The three failures had resulted from cracks in the restorations, which had not clinically debonded. No secondary caries was detected at the crown margins, and anatomic form was assessed as excellent for 56 crowns. Root canal treatment had been required in one case. Color match was rated very good for 47 crowns. All 25 patients were satisfied with their restorations. CONCLUSION: Dentin-bonded crowns may be found to have a low rate of failure and to provide a high level of patient satisfaction.     

The aesthetic composite anterior single crown restoration

Achieving natural aesthetics by harmoniously matching the shape and color of a single anterior crown is perhaps one of the greatest challenges in restorative dentistry. The clinician must often rely on the artistic skills of a laboratory technician who has no direct access to the patient. The shade selection process is, therefore, impaired, and the final result may be a restoration which does not emulate the aesthetics of the adjacent natural dentition. The learning objective of this article is to present an innovative technique which utilizes the qualities of high strength laboratory processing in association with the application of light curing and freehand bonding of composite resins. This combination allows the clinician to predictably achieve aesthetic results with single anterior crowns. The direct, indirect, and indirect/direct restorations are discussed, and the laboratory and clinical procedures are reviewed.     

Intermittent mental paraesthesia in an edentulous mandible

A patient presenting with bilateral intermittent mental paraesthesia on wearing a lower denture on a very atrophic ridge was treated with an implant-retained overdenture which resolved her symptoms.     

Marginal discrepancy of all-ceramic crowns cemented on implant abutments

PURPOSE: The purpose of this investigation was to determine the mean marginal discrepancy of all-ceramic crowns cemented on implant abutments. MATERIALS AND METHODS: Five Br?nemark CeraOne abutments were connected to implant fixtures embedded in acrylic resin blocks. The marginal discrepancy was measured using a video camera connected to a digitizing board at four locations on each abutment for five samples in each of the following groups: all-ceramic caps (caps), all-ceramic crowns (crowns), and all-ceramic crowns cemented with zinc phosphate cement (cemented crowns). RESULTS: The mean marginal discrepancies were as follows: caps, 99.0 micrometers (SD, 16); crowns, 117.8 micrometers (SD, 20); and cemented crowns, 168.8 micrometers (SD, 23). Statistically significant differences were found between all three groups at the 99% level of confidence. In addition there were two significant differences between abutments. CONCLUSIONS: Subgingival marginal discrepancies of the magnitude measured in this study have been shown to cause periodontal problems. It is probable that the marginal discrepancy of CeraOne restorations, as tested, can be improved. Efforts should be made to enhance the marginal accuracy of these restorations.     

Clinical disorders of magnesium metabolism

Dental care of the aging patient presents a number of problems not encountered in younger patients. Most of these problems result from tissue changes that occur during aging. Dental implants and implant-retained and/or implant-supported prostheses are viable treatment options for older patients. The majority of elderly patients in their younger retirement years are relatively healthy and not limited in activity. The clinician must be aware of the physical, metabolic, and endocrine changes associated with aging and how these changes may affect implant treatment. The elderly deserve the best care the dental profession can offer.     

New players and puzzles in the Hedgehog signaling pathway

STATEMENT OF PROBLEM: Esthetic demands of patients and practitioners for an all-ceramic crown in both anterior and posterior regions of the dental arches has prompted the development of the Procera AllCeram crown. Long-term clinical trials that evaluate the strength and naturalness of the Procera AllCeram crown are lacking. PURPOSE: This prospective study was initiated to evaluate the clinical performance of 100 Procera AllCeram crowns after 5 years in service. MATERIAL AND METHODS: One hundred Procera AllCeram crowns were fabricated for 58 patients (20 men and 38 women). Patients were treated by 4 general dental practitioners. Crown placement involved both the anterior and posterior regions of the dental arches. Crowns were examined at baseline and once a year during the 5 years that followed and evaluated at each appointment with the California Dental Association's quality assessment system. RESULTS: Of the 97 crowns remaining in the study after 5 years, only 3 crowns had experienced a fracture through the veneering porcelain and the aluminum oxide coping material. Two additional crowns were replaced as a result of fractures of only the veneering porcelain. One crown was replaced as a result of recurrent caries. All remaining crowns were ranked as either excellent or acceptable for surface/color, anatomic form, and marginal integrity. CONCLUSION: The 5-year clinical observations and ranking with the California Dental Association's quality assessment criteria supported the conclusion that Procera AllCeram crowns may be used in all areas of the mouth.     

Electrical discharge machining

This article describes a laboratory technique of achieving the highest degree of passive fit of an implant-retained restoration using electric discharge machining (EDM). This process can save time by eliminating the need for conventional soldering procedures, increase the longevity of the restoration, and when used along with the clinical technique of fabricating a verification index, eliminate the clinical try-in phase.     

Precision of fit: the Procera AllCeram crown

STATEMENT OF PROBLEM: Strength, color stability, and precision of fit are requirements for all-ceramic restorations. The Procera AllCeram crown system, composed of a densely sintered high-purity alumina core combined with a low fusing surface porcelain, appears to satisfy most of these requirements. However, evaluation of marginal fit has not been reported. PURPOSE: This study measured the precision of fit of the Procera AllCeram crown fabricated with Procera CAD/CAM technology for the premolar and molar teeth fit to a die. MATERIAL AND METHODS: Five ivorine maxillary first premolars and first molars were prepared for full-coverage crowns. Preparations were standardized with a convergence angle of 10 degrees, chamfer margins of 1.3 to 1.5 mm circumferentially, and occlusal reduction of 2.0 mm. AllCeram crowns were fabricated for the dies, and the fit of the crown to the die was determined by using a standardized procedure with a silicone impression material that served a dual role: (1) as a retrievable luting agent, and (2) to replicate the internal aspects of the crown. Laser videography was used to measure the gap dimension between the crowns and the dies at the marginal opening, the axial wall, the cusp tip, and the occlusal adaptation measurement locations. Mean gap dimensions and standard deviations (SDs) were calculated for marginal opening, internal adaptation, and precision of fit. RESULTS: Mean gap dimensions and standard deviations at the marginal opening for the premolar and molar crowns were 56.0 microns SD +/- 21 and 63.0 microns SD +/- 13 microns, respectively. The mean gap dimensions and SDs of the internal adaptation were 69.0 microns SD +/- 17 microns for axial wall, 48.0 microns SD +/- 12 microns for cusp tip, and 36.0 microns SD +/- 7 microns for occlusal adaptation for the premolar crowns; and 49.0 microns SD +/- 3 microns axial wall, 67.0 microns SD +/- 21 microns cusp tip, and 74.0 microns SD +/- 29 microns occlusal adaptation for molar crowns. Precision of fit and SDs for premolar and molar crowns were 52.0 microns SD +/- 19 microns and 63.0 microns SD +/- 20 microns, respectively. Mean marginal openings and precision of fit gap dimensions for the crown groups were not significantly different at the .05 level. However, gap dimensions that defined the internal adaptation at the measurement locations were different (P < or = .05). CONCLUSION: Mean gap dimensions for marginal openings, internal adaptation, and precision of fit for the crown groups were below 70 microns. These findings show that the crowns studied can be prescribed with confidence knowing that the precision of fit will consistently be less than 70 microns.     

Epinephrine in digital blocks: revisited

STATEMENT OF PROBLEM: Implant treatment in the United Kingdom has been provided mainly in specialist, regional dental hospitals. However, increasingly, general dentists are providing implant-supported prostheses in a private office setting. PURPOSE: This study investigated the nature, timing, and frequency of complications associated with single tooth implant therapy in a dental hospital and two dental offices. METHODS: The dental records of 58 patients provided with 76 implants during the period of 1989-95 were reviewed retrospectively. Fifty-three single tooth crowns on implants were placed by general dentists and 23 by specialists in the dental hospital. RESULTS: Implant survival rate was 96%. Twenty-eight guided bone regeneration procedures were required, including 13 unplanned ones. Prosthodontic complications included the need for recontouring of three crowns and the recementation of three crowns. Only two abutment screws required retightening. Peri-implant soft tissue inflammation occurred around six crowns and recession around two. CONCLUSION: The single tooth implant-supported crown appears to be an effective and durable restorative treatment with a relatively low prevalence of postoperative complications.     

The versatile and esthetic metal-ceramic crown

The predictability, many advantages and remarkable adaptability of metal-ceramic crowns account for their frequent use. Metal-ceramic crowns will continue to be one of the most widely used dental restorations.     

Vital tooth esthetics in Captek restorations

Captek crowns and bridges employ optical effects that simulate vital tooth esthetics. The intensive red color of the blood in the vital pulp plays an important role in natural tooth appearance. This role is often ignored in restoration construction and results in a dead-looking restored tooth. To achieve optimal tooth esthetics, it is essential to mimic these often overlooked esthetic qualities.     

Marginal adaption of two esthetic complete crowns

In an in-vitro study twenty artificial crowns were fabricated. A hardened stainless steel five piece die assembly was used to construct uniformed wax patterns and to record all measurements. The fit of ten PFM crowns before and after the application of porcelain using the porcelain but margin technique was compared to that of ten Dicor crowns. The results of this study indicated best fit with the metal crowns before the application of porcelain, while the PFM crowns were oversized and the Dicor crowns were undersized.     

Procera: a new way to achieve an all-ceramic crown

The Procera System embraces the concept of computer-assisted design and computer-assisted machining to fabricate an all-ceramic crown composed of a densely sintered, high-purity aluminum oxide coping combined with a compatible veneering porcelain. Strength, precision of fit, color stability, cementation, and wear characteristics are among the many factors that concern clinicians when fabricating all-ceramic restorations with this new crown system. This article presents, in summary form, the data from the many studies on Procera AllCeram crowns that have been conducted at clinical and laboratory centers around the world. The evidence reported in these studies clearly demonstrates that the Procera AllCeram crown represents a combination of computer technology and creativity for which a positive prognosis can be made. Today its application is restricted to single crowns; however, with continued development, multiple unit all-ceramic anterior and posterior fixed partial dentures are clearly in the future.     

Anterior maxillary aesthetics utilizing all-ceramic restorations

The use of all-ceramic systems has increased significantly during recent years, due to the improved strength and the introduction of a new generation of dental adhesive agents and resin cements. Both factors permit reliable and predictable results in single jacket crown restorations in the maxillary anterior region. Due to their natural appearance, the all-ceramic materials, especially the glass ceramics, blend harmoniously with the oral environment and are particularly appreciated where aesthetics is a priority. The learning objective of this article is to demonstrate a routine utilization of all-ceramic systems in the maxillary anterior region, preceded by a proper case selection. Two clinical cases are used to illustrate the preparation procedure, the importance of well-integrated provisional restorations, and the accuracy in transferring provisional information onto the final jacket crowns.     

Clinical commissioning of Laitinen Stereoadapter for fractionated stereotactic radiotherapy

PURPOSE: The purpose of this study was to investigate the distribution of shades selected for metal ceramic crowns provided at a dental teaching hospital. MATERIALS AND METHODS: Data on the selection of shade for 2,500 metal ceramic crown units, placed over a 5-year period at the University Dental Hospital of Manchester, were collected and analyzed. Only those crowns placed adjacent to minimally restored vital teeth were included in the study. RESULTS: The results indicate that the most frequently chosen shades were in the mid-range of reddish-brown hue. Furthermore, shades in the reddish-grey range of hue were rarely chosen. The selection of more than one shade for a crown ("mixed shades") was generally restricted to the maxillary anterior teeth. CONCLUSION: Knowledge of the distribution of shades selected for permanently luted metal ceramic crowns may be a useful adjunct in shade selection, particularly for the inexperienced operator.     

Blood transfusion practices in Mwanza Region, Tanzania. Bugando Medical Centre

Uncertainty exists about the forces applied by dentists during dental crown cementation. A measuring system was developed based around a commercially available miniature (3.8 mm high and 12.7 mm diameter) load cell. The load cell was mounted in a finger stall and the applied force measured. Experimental results suggest that dentists typically apply a force to metal crowns of about 60 N for a few seconds, followed by the application of a steady force of about 20 to 30 N. Lower forces are applied to porcelain crowns.     

Problems associated with the atrophic mandible

A range of treatment options has been presented regarding the use of dental implants to rehabilitate patients who otherwise have compromised function using conventional tissue-borne prostheses. This patient population offers significant challenges to both the surgeon and the prosthodontist. Generally speaking, IODs retained on two or more endosteal osseointegrated implants; transosteal, subperiosteal, ramus frame implant-supported and implant-retained prostheses, and a totally implant-supported design offer options to treat the severely atrophic mandible. When bone support or volume is so lacking that augmentation procedures are required, bone grafting can be considered as a treatment option. The state-of-the-art of implant treatment for the atrophic mandible offers to the dental professional and patient a variety of options. Thus far, it is too early to make specific recommendations as to which treatment offers the best option for each patient. It is fair to say that the ISP remains the gold standard against which other treatments can be compared.     

Changes in esophageal function after vertical banded gastroplasty as demonstrated by esophageal scintigraphy

STATEMENT OF PROBLEM: Earlier studies on orthodontic brackets have shown a loss of bond strength after a sonic toothbrush was used. PURPOSE: This in vitro study evaluated the difference in bond strength of single complete veneer crowns after being subjected to the equivalent of 2 years of brushing with sonic and counterrotational toothbrushes. MATERIAL AND METHODS: Complete gold crowns were fabricated with a conventional indirect technique for 30 extracted, intact, prepared human premolar teeth. Castings were then luted to the teeth with glass ionomer cement. Teeth were randomly divided into 3 groups of 10 teeth each, 1 group to be brushed with Sonicare sonic toothbrush, 1 group to be brushed with Interplak counterrotational mechanical toothbrush, and 1 group as the control. Groups 1 and 2 were then brushed for the equivalent of 2 years per tooth. A uniform force of 50 g for the sonic toothbrush and 120 g for the counterrotational toothbrush was used. Control specimens were not brushed. Brush heads and sample teeth in contact with the toothbrush were kept moist at all times. Tensile dislodgment force was determined with an Instron universal testing machine. RESULTS: The castings brushed with a sonic toothbrush required a mean of 43.22 kg (+/- 11.16) force to remove the crowns from the teeth, whereas the counterrotational group required a mean of 42.87 kg (+/- 10.42) and the control group a mean of 42.12 kg (+/- 6.61). Analysis of variance on the force data indicated no differences among the 3 groups in the force needed to remove the castings (F[2,24] = 0.031, P = .97). CONCLUSION: This in vitro study demonstrated no significant differences between groups in the amount of tensile dislodgment force required to remove cemented full veneer crowns from prepared teeth after brushing for the equivalent of 2 years time with a sonic toothbrush or a counterrotational toothbrush.     

The epidemiology, clinical characteristics, and natural history of older nursing home residents with a diagnosis of Parkinson''s disease

This study investigated the occlusal stress distribution to the implant and soft tissue for the implant-retained overdenture. The stress at the molar residual ridge and the strain around the implant were measured on an experimental resin cast using static and dynamic loading. The influence of connecting structures of stud attachments on stress distribution was discussed. The occlusal stress had a tendency to concentrate on the implant, especially in the areas distal to the implant. The modified magnetic attachment system, using a silicone-covered magnet, provided the optimal stress distribution.     

The effect of adhesive luting agent-dentinal surface interactions on compressive strength of two types of all-ceramic crowns

This research compared the compressive strength of two types of all-ceramic crown (Hi-Ceram and Duceram) as affected by selected luting cements (Zn phosphate, glass ionomer and composite resin cement). Thirty crowns of similar size and shape were constructed (15 crowns of each tested material) to fit a standard posterior tooth preparation. Five crowns from each material were cemented by one of the tested cements. The cemented crowns were loaded until catastrophic failure. A two-way analysis of variance was performed and showed that the type of utilized cement had a significant effect on the compressive strength being that Panevia Ex. resin cement the most effective one followed by glass ionomer and then finally zn phosphate cement. Statistical analysis also showed that Hi-Ceram crowns were more resistant to occlusal load than Duceram.