A three-die cast technique for duplicating free gingival form in zirconia crowns: two case reports

This report describes a duplication technique of free gingival form from a provisional restoration to a zirconia crown. Three die casts were manufactured from a silicone impression with an acrylic resin ring tray. The first die cast was for the zirconia framework, the second for the provisionalized transfer coping, and the third for relining the provisional restoration. A free gingival impression was taken using a provisionalized transfer coping, and a soft gingival cast was manufactured. The depth of free gingival transparency was measured using a zirconia shade plate. Then, the zirconia framework was customized to allow for subgingival porcelain space. This technique seems to contribute to the clinical-laboratory interface in computer-aided design/computer-assisted manufacture restorations.

A free gingival impression for achieving optimal interdental papilla height: a case report

Failure to tend to inadequate crown contours in the crown trial can cause long-term disharmony of the free gingival form. This case report describes a novel technique for free gingival impression from a final provisional restoration to a zirconia crown. Two die casts were manufactured from a silicone impression. The first die cast was for the zirconia crown; the second die cast was for the final provisional restoration and the provisionalized transfer coping. A free gingival impression was taken using a provisionalized transfer coping, and a soft gingival model was manufactured. The proximal contact position was managed using the predicted convex curve of the interdental papillae. One year after zirconia crown placement, no inflammation was observed around the pyramidal interdental papillae, and symmetric interdental papilla heights were evident. A free gingival impression using a two die-cast technique appears to be useful for achieving optimal interdental papilla height.

The concept of the interdental gingival midpoint line in cervical line management

The first purpose of this study was to investigate the relationship between the lowest cervical point and the interdental gingival midpoint (IGM) line in the maxillary anterior region. After marking the lowest cervical points and the mesial and distal interdental gingival midpoints on study models of 77 patients, the shortest distances from the IGM lines that connect both interdental gingival midpoints to the lowest cervical points were measured on silicone impressions. The findings showed that the average position of the lowest cervical points in the central incisors coincides with the IGM line. This position is located 0.24 mm palatally in the lateral incisors, and in the canines 0.3 mm facially from the IGM line. The second purpose of the study was to verify the IGM line concept in cervical line management through some clinical cases. In a thick-flat biotype case using a clinical crown lengthening procedure, the lowest cervical points were adjacent to the IGM lines following long-term coronal gingival growth. In a short-term observation of a thin-scalloped biotype case, untouched facial gingiva increased following interdental gingival augmentation. In a case of Miller class 1 gingival recession, a coronally advanced flap combined with the roll technique was performed based on the IGM line concept. According to the results obtained from this study and these cases, it seems that the IGM line could become a diagnostic standard in cervical line management in periodontal plastic surgery.

Biologic height-width ratio of the buccal supra-implant mucosa

Recently, esthetic implant dentistry has focused on changes in buccal implant mucosal height. The purpose of this article was to investigate the relationship between the height and width of buccal supra-implant mucosa based on the physiologic mucosal form surrounding the implant. Fourteen patients who had buccal supra-implant mucosal heights of more than 1.5 mm and keratinized mucosa 1 year or more after superstructure placement (average period: 3 years 5 months) were studied. Silicone impressions were taken immediately after superstructures and abutments were removed. The study model used for the measurement process was manufactured using improved dental stone. The height and width of the buccal supra-implant mucosa were measured using digital slide calipers, and the ratio of the height and width was investigated. In all cases, the widths were greater than the heights. The average height of the buccal supra-implant mucosa was 2.17 mm, while the average width was 3.44 mm. The average biologic height-width ratio was 1:1.58. The width was larger in the posterior region than in the anterior. There were no differences in the biologic height-width ratio in terms of the diameter of the implant. These findings indicate that peri-implant soft tissue augmentation procedures resulting in an average biologic height-width ratio of 1:1.5 may provide a stable buccal cervical line around the implant superstructure, even for thin periodontal biotypes.

Cloning and sequencing of the cDNA encoding beta-glucosidase 1 from Aspergillus aculeatus

A cDNA was isolated from an Aspergillus aculeatus cDNA library using synthetic oligodeoxyribonucleotide mixtures that corresponded to the internal amino acid (aa) sequence of mature beta-glucosidase 1 (BGL1). Analysis of the nucleotide sequence of the cloned cDNA insert revealed a 2580-bp open reading frame (ORF) that encoded a 860-aa protein. The deduced aa sequence of the ORF shared sequence similarity with several BGL from other microorganisms.