Quintessence International, 07/1996

This study was undertaken to investigate the outcomes in 20 children and adolescents who had undergone an intracoronal nonvital bleaching technique. Twenty-one discolored central incisor teeth were treated by the walking bleaching method and reviewed at intervals for 18 months following completion of bleaching. All teeth bleached lightened to varying degrees, and 62% of patients expressed satisfaction with the result. When a porcelain shade guide was used as a reference before bleaching, the percentage of teeth deemed off the shade guide, gray or reddish gray, was 97%. Immediately postbleaching, the percentage had been reduced to 57%, and relatively more teeth were at the lighter end of the scale for each color band. At 18 months, three teeth (17%) had been veneered, and 33% of the remainder were found to be off the shade guide, gray or red-gray. Radiographically, 81% of teeth were classified as healthy at 18 months, with no evidence of cervical or progressive apical resorption.

The Scanora spiral tomography system can be used to solve a range of imaging problems in the maxillofacial region. However, teh system has no specific programs for imaging bony lesions of the hard palate or medially and cranially displaced maxillary third molars. New patient-positioning techniques were therefore developed on the basis of phantom radiographs, and their successful application in patients is presented. With the novel techniques, good radiographic representations of the hard and soft palates in the posteroanterior and lateral projections and of maxillary third molars were achieved

Tooth rotation and periodontal breakdown has not been thoroughly studied due to lack of quantitative tools. The purpose of the present study was to examine this correlation, with respect to alveolar bone loss, from direct observation of 17 skulls. A photograph of the mandibular occlusal plane was taken from a fixed reference point, and the midcentral fossa and the extreme mesial and idstal points of each tooth were marked on the photograph. A computer program established the arch form of each mandible from the midtooth landmarks. The angle between individual teeth and the arch (at any given point) was calculated. Bone loss, indicated by the distance of the bone crest from the cementoenamel junction, was measured at six reference points around each tooth with a caliper. A positive correlation, though weak, was found between increased tooth rotation and greater bone loss. Mean bone loss of teeth with rotation of 20 degrees and greater was 4.03 mm, while that of teeth with less than 20 degrees of rotation was 3.49 mm.

It has been asserted that the average height of natural teeth in Mediterranean Latin populations is relatively short and that these teeth are of insufficient size to host standard attachments manufactured by different companies. The occluogingival height of 159 potential abutment teeth from 50 Spanish patients was measured and compared to the sizes of intracoronal and extracoronal attachments available from one manufacturer. Twenty-one abutments (13% of the sample) were smaller than the smallest intracoronal attachment available. Eighty-seven percent of the abutments in the sample would have allowed the use of an attachment. However, only 11% of the sample would have allowed the use of a large intracoronal or medium extracoronal attachment, and none would have been able to host a large extracoronal attachment. In addition, 35% of the sample could only have accepted a small intracoronal attachment. In such cases, the capacity for retention would have to be carefully evaluated.

This case report describes a simplified orthodontic system for the management of a palatally impacted canine accompanied by root resorption of of incisors. The anchorage for this sytem is the transpalatal arch and a heavy buccal segment arch wire with two loops soldered to stainless steel bands. This type of stationary anchorage provides stability by uniting both molars across the palatal vault and thus avoids the need for bonding of adjacent mobile teeth. With this system an impacted canine can be extruded, moved distally, jumped over the occlusion, and derotated. The efficiency of this appliance makes it a safe method for moving teeth through simple manipulation and with minimal esthetic inconvenience.

Supernumerary teeth are considered to be among the most significant dental anomalies affecting the primary and the early mixed dentitions. Early removal of such teeth is recommended if they impede the eruption of adjacent permanent teeth, appear inverted or rudimentary, or are associated with certain pathologic conditions. This report describes the appearance of late-developing supernumerary teeth in the premolar region in three quadrants.

The intraradicular reinforcement of structurally compromised roots has been advocated for endodontically treated teeth with thin remaining walls. The purpose of this in vitro study was to investigate the validity of intraradicular reinforcement. After the crowns were removed, forty structurally weakened central incisors were divided into two main groups for morphologic dowel rehavilitation or resin reinforcement and dowel rehabilitation. Within both these groupings, half the specimens were ferruled to assess the effects of a ferrule on fracture resistance. All dowels were cemented with resin cements. The resistance to a simulated masticatory load of a resin-reinforced p[ost and core system was significantly greater than that of a morphologic post and core procedure. When a bonded resin reinforcement and dowel cementation was used on structurally weakened roots, there was no statistically significant difference between post and core restorations that used a ferrule and those without a ferrule.

This study investigated changes in the marginal adaptation and surface morphology of Ketac-Silver and Chelon-Silver glass-cermet cements over time. Dispersalloy amalgam was used as a control Contralateral pairs of carious primary molars were restored with the test materials and amalgam. Clinical evaluations were scheduled at 12, 18, adn 24 months after placement. Gold-plated replicas of the restorations were observed with scanning electron microscopy. Fractures and cracks in the surface of the Sispersalloy and Chelon-Silver increased the surface roughness; however, the damage was superficial and self-limiting in the Dispersalloy restorations, while in Chelon-Silver the fractures caused the material to break down in layers. A substantial quantity of pores, usually smaller than 50 um in diameter, were observed throughout the surface of the Chelon-Silver restorations. The pores in teh surface of Ketac-Silver were fewer and smaller. The incidence of cavomarginal breakdown increased with time. Chelon-Silver restorations had a higher rate of cavomarginal breakdown than did Ketac-Silver and Dispersalloy restorations up to 18 months. However, there was no statistically significant difference in the marginal adaptation of the three groups at 24 months.