International Journal of Esthetic Dentistry (EN), 01/2009

Crowns and veneers provide distinct treatment strategies with different outcomes in terms of tissue conservation, periodontal distress and esthetic result. It is not always clear where a crown or veneer is indicated, but in the last two decades, adhesive technology, conservative approaches and esthetic demands have increased clinical indications for porcelain veneers in restorative dentistry. A combination of veneers and crowns may be required, especially in the anterior region. It may be desirable to reinforce some teeth and preserve tissue on others. Problems can arise with the esthetic integration of both types of restoration, owing to their inherent mechanical and optical properties. Several clinical and laboratory techniques can be applied for a successful combination. In this article the authors describe the procedures and difficulties in treating a case with such needs.

The present study evaluated gingival recession 1 year following apical surgery of 70 maxillary anterior teeth (central and lateral incisors, canines, and first premolars). A visual assessment of the mid-facial aspect of the gingival level and of papillary heights of treated teeth was carried out using photographs taken at pre-treatment and 1-year follow-up appointments. In addition, changes in the gingival margin (GM) and clinical attachment levels (CAL) were calculated with the use of clinical measurements, that is, pre-treatment and 1-year follow- up pocket probing depth and level of gingival margin. Changes in GM and CAL were then correlated with patient-, tooth-, and surgery-related parameters. The following parameters were found to significantly influence changes in GM and CAL over time: gingival biotype (P 0.05), with thin biotype exhibiting more gingival recession than thick biotype; pre-treatment pocket probing depth (PPD) (P 0.03), with cases of pre-treatment PPD 2.5 mm demonstrating more attachment loss than cases of PPD >= 2.5 mm; and type of incision (P 0.01), with the submarginal incision showing considerably less gingival recession compared with the intrasulcular incision, papilla-base incision or papillasaving incision. The visual assessment using pre-treatment and 1-year follow-up photographs did not demonstrate significant changes in gingival level or papillary height after apical surgery. In conclusion, gingival biotype, pre-treatment PPD, and type of incision may significantly influence changes in GM and CAL following apical surgery in maxillary anterior teeth.

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.

The aim of this two-part treatment series is on the one hand to emphasize the difficulties and dilemmas a dentist is confronted with when planning complex cases, and on the other hand to reveal the rationale supporting the final treatment plan selection. Challenging cases are considered, including, among others, periodontal compromised rest dentitions requiring prosthodontic rehabilitation. For these patients the decision-making process deals with the indications and limitations of both the fields of fixed and removable prosthodontics. The first part of this study deals with the various prosthodontic treatment options together with the advantages and disadvantages related to each one. The second part of the article presents the final treatment- plan, the decision-making process and the sequence of the treatment steps.

This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (lightemitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 ± 0.622 µg) compared with groups that were not (0.198 ± 0.218 µg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.