Quintessence International, 07/2010

When a tooth with an apical lesion is identified, an apicoectomy is frequently performed when nonsurgical treatment is considered unfeasible or has previously failed. However, the treatment is usually difficult in molars. This article describes a minimally invasive procedure for removing a gutta-percha point under the maxillary sinus mucosa using an ultrathin arthroscope and a visualization approach in apicoectomy using an intranasal endoscope. These surgical techniques using endoscopes are minimally invasive and reliable procedures that provide limited incision and bone removal and respect the integrity of the maxillary sinus. Keywords: apicoectomy, endoscope, gutta-percha point removal, periradicular surgery

A case is reported of a 20-year-old woman with generalized severe gingival overgrowth covering almost all of the teeth with diastemata, diagnosed as idiopathic gingival fibromatosis. After initial therapy, the patient underwent surgery consisting of a full-mouth internal beveled gingivectomy. Postoperatively, the maxillary anterior teeth spontaneously moved to almost optimal positions. Removing the cause by gingivectomy can lead to spontaneous correction of the pathologic tooth migration. With supportive periodontal treatment, the patient showed no recurrence of gingival enlargement or repositioning of the teeth at the 5-year follow-up. Keywords: gingival fibromatosis, gingival overgrowth, gingivectomy, tooth movement

Gingival recession presents a multifactorial etiology that may be associated with anatomical, physiologic, or pathologic factors. Several surgical techniques are described to manage the gingival recession. The buccal fat pad is a specialized organized fat tissue that maintains its volume and structure over a long period of time. It can also serve as a wellvascularized, readily obtainable local flap for reconstructive purposes as root coverage for severe recession defects, increasing the dimensions of keratinized mucosa. The aim of this case report is to establish a new technique for root coverage using pedicled buccal fat pad in Miller Class III recession on the maxillary right first molar. Keywords: buccal fat pad, gingival recession, root coverage

DiGeorge syndrome, which is caused by a microdeletion of 1.5 to 3.0 megabases on the long arm of chromosome 22, has an incidence of approximately 1:4,000 to 1:5,000 live births. The phenotypic spectrum of this disorder includes congenital heart defects, immunodeficiency due to thymic hypoplasia or aplasia, transient or permanent hypocalcemia due to parathyroid hypoplasia or aplasia, developmental retardation, and psychiatric disorders. Dental aspects in these patients include skeletal malformations, velopharyngeal insufficiency with or without cleft palate, small mouth, and hypotonus orofacial musculature, as well as impaired salivary flow. Enamel aberrations related to hypocalcemia may result in a higher frequency of dental caries. Based on a series of five patients, the medical and dental aspects that have to be considered in the care of patients with DiGeorge syndrome are presented. Keywords: caries risk, DiGeorge syndrome, CATCH 22, genetic disorder, hypomineralization

Objective: To compare the clinical outcomes of mineral trioxide aggregate (MTA) used as root-end filling with other materials in endodontic surgery to determine which modality offers more favorable outcomes. Method and Materials: A computerized literature search was performed in the Cochrane Library (1993-2009), MEDLINE (1993-2009), EMBASE (1993-2009), Science Citation Index (SCI) (1993-2009), Chinese Biomedicine Database (1993-2009), and China National Knowledge Infrastructure (CNKI) (1993-2009) to collect randomized controlled trials and quasi-controlled trials comparing MTA with other materials or placebo. The Cochrane Collaboration's RevMan5 software was used for data analysis. Results: Five studies involving MTA and three other materials were included. No statistically significant difference was found in the clinical effectiveness of MTA and intermediate restorative material (IRM), with relative risk (RR) 0.62 and 95% CI 0.34 to 1.16. A statistically significant difference exists between MTA and amalgam in terms of outcome, with RR 0.35 and 95% CI 0.13 to 0.94. The difference between the gutta-percha and the MTA groups was statistically significant, with RR 0.08 and 95% CI 0.01 to 0.57. Conclusion: MTA as root-end filling is better than amalgam and purely gutta-percha but similar to IRM. There is a limited number of well-designed clinical trials within this research area. Further highquality, large-scale, and long-term follow-up randomized controlled trials are still required to confirm the long-term outcomes of MTA as root-end filling in endodontic surgery. Keywords: endodontic surgery, meta-analysis, MTA, RCT, root-end filling, root-end resection

Objective: Porcelain veneers have become an interesting treatment option to correct the shape and color of anterior teeth. Because of their limited thickness and high translucency, achieving a good color match is influenced by several variables. The aim of this work was to investigate the influence of natural dentin and resin cement colors on final color match of porcelain veneers. Method and Materials: A preselected shade tab (A1) was chosen as the target color for a maxillary central incisor, and its color parameters (L*a*b*) were measured using a digital spectrophotometer (SpectroShade, MHT). Nine natural dentin colors (Natural Die Material, Ivoclar Vivadent) representing a wide range of tooth colors were used to prepare resin replicas of the maxillary central incisor with a standard preparation for porcelain veneers. The prepared porcelain veneers (IPS Empress Esthetic, A1, 0.6 mm thick, Ivoclar Vivadent) were cemented on the resin dies (nine groups of natural dentin colors) using seven shades of resin cement (Variolink Veneers, Ivoclar Vivadent). The L*a*b* values of the cemented veneers were measured, and ΔE values were calculated against the preselected target color (A1). ΔE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. Results: The seven shades of resin cement had no significant influence on the final color of the veneers, as the measured ΔE values were almost identical for every test group. On the other hand, the color of natural dentin was a significant factor that influenced final color match. None of the 63 tested combinations (nine natural dentin colors and seven resin cement colors) produced an acceptable color match. Conclusion: Thin porcelain veneers cannot mask underlying tooth color even when different shades of resin cement are used. Incorporation of opaque porcelain (high chroma) may improve final color match. Keywords: cement, dentin color, masking, spectrophotometer, target color, veneer

Reduced alveolar bone height is very common in the posterior jaws. The current treatment modality to replace the missing teeth with an implant-retained fixed partial denture includes sinus bone grafting in the maxilla and onlay bone graft in the mandible. These procedures are invasive and require more time and cost. Short dental implants are used as an alternative treatment modality to bone grafting procedures. To enhance success rate, certain principles should apply. Short implants could provide comparable results to those of longer implants. This article reviews the current literature on the use of short implants, discusses the biomechanical considerations when utilizing short implants, and presents a case. Keywords: alveolar bone, fixed partial denture, short implant, sinus lift

The literature reports an increasing occurrence of carcinoma in the young adult nonsmoking and nondrinking population. With it, this trend brings the potential for new comorbidities. This report discusses one such case in which a 30-year-old woman, 28 weeks pregnant, was diagnosed with a hybrid verrucous carcinoma/squamous cell carcinoma. Several years preceding the presentation of the hybrid lesion, the patient had an odontogenic cyst associated with the same region. The original lesion was reported to have mucosal change overlying it. Newly available immunohistochemical stains were used to review the lesion to assess the potential for aggressiveness and proliferative changes. All the biomarkers were unremarkable, suggesting that the progression of the initial lesion could not have been predicted with the current immunohistochemical stains. This report discusses the diagnosis and treatment of this unusual scenario involving progression of a benign lesion to a malignant hybrid. Keywords: dentigerous cyst, HPV, immunohistochemical stains, keratocystic odontogenic tumor, P53, PCNA, squamous cell carcinoma, verrucous carcinoma

Objective: To compare in vitro the marginal adaptation of crowns manufactured using ceramic restoration fabricating techniques. Method and Materials: Fifty standardized master steel dies simulating molars were produced and divided into five groups, each containing 10 specimens. Test specimens were fabricated with CAD/CAM, heat-press, glass-infiltration, and conventional lost-wax techniques according to manufacturer instructions. Marginal adaptation of the test specimens was measured vertically before and after cementation using SEM. Data were statistically analyzed by one-way ANOVA with Tukey HSD tests (α = .05). Results: Marginal adaptation of ceramic crowns was affected by fabrication technique and cementation process (P < .001). The lowest marginal opening values were obtained with Cerec-3 crowns before and after cementation (P < .001). The highest marginal discrepancy values were obtained with PFM crowns before and after cementation. Conclusion: Marginal adaptation values obtained in the compared systems were within clinically acceptable limits. Cementation causes a significant increase in the vertical marginal discrepancies of the test specimens. Keywords: all-ceramic, CAD/CAM, marginal discrepancy, marginal fit

Scaling and root planing are probably the most important procedures in periodontal therapy, yet periodontal instrument identification requires visual refocusing from a patient to the tip of an instrument, an inefficient activity in terms of time and ergonomics. For instructors teaching periodontal instrumentation, identifying whether a student is using a correct instrument requires that the instrument be removed from a patient's mouth for inspection. This technique report shows how color coding instruments can simplify the instrumentidentification process. Typically, dental professionals in private practice use a series of color-coded bands or collars on instrument handles to keep track of instrument inventory within dental cassettes. In most cases, the instruments within a particular set are assigned one color so that one can easily identify which instrument goes with which set and determine if all instruments within a particular set are present. The author proposes using a series of colors with a specific color identifying a specific instrument. As long as auxiliaries know which colors must be present in a cassette, the practitioner or dental faculty member can easily identify what instrument is required. Keywords: color coding, dental education, identification, instrument inventory, periodontal instruments

Objectives: In this in vitro study, the authors sought to determine the effects of 1.23% acidulated phosphate fluoride gel (APF) or drinkable yogurt on human enamel after exposure to an acidic drink. Method and Materials: Sixteen surgically removed, caries-free, human third molars were cut into four portions: mesial, distal, buccal, and lingual. Each portion was distributed into one of four groups, with each specimen embedded in acrylic resin and its enamel center lightly ground and polished. Three groups of specimens were immersed in orange juice for 2 minutes. One group received no other treatment (OR), one group was subsequently immersed in drinkable yogurt for 5 minutes (OR:YO), while another group had 1.23% APF applied for 4 minutes (OR:APF). The final group was immersed in only drinkable yogurt for 5 minutes (YO). Each exposure was performed twice daily for 60 days; between exposures, the samples were stored in artificial saliva. The enamel surfaces were monitored by three criteria: erosion depth, surface hardness, and SEM. Results: Erosion depth increased progressively in all groups. Surface microhardness progressively decreased in all groups except the OR:APF group, where hardness was significantly higher than other groups at 60 days (P < .05). SEM inspection revealed preferential loss of rod crystallites with retention of interrod crystallites in all specimens exposed to orange juice. The enamel exposed to only drinkable yogurt revealed modest and uniform etching. Conclusion: Drinkable yogurt alone or posttreatment of enamel after exposure to an acidic drink with either 1.23% APF or drinkable yogurt leads to enamel dissolution and does not reduce enamel erosion, in vitro. Keywords: 1.23% acidulated phosphate fluoride gel, drinkable yogurt, enamel erosion, in vitro

Objective: To evaluate whether alveolar ridge resorption following tooth extraction could be prevented or reduced using absorbable collagen material impregnated with gentamicin and sealed with an autogenous soft tissue graft to stabilize the extraction clot, and to compare this with natural healing by clot formation using a classic extraction technique. Method and Materials: A total of 125 patients providing 173 extraction sites were included in the study. Three extraction protocols were compared: atraumatic extraction (group A, n = 101 extraction sites), atraumatic extraction sealing the socket with autogenous soft tissue graft (group B, n = 39), and atraumatic extraction with socket seal surgery and collagen matrix impregnated with gentamicin (group C, n = 33). Silicone impressions were made before and 3 months after extraction. Casts were used to measure the width of the alveolar bone at the extraction area using the incisal edge of the adjacent teeth as a reference point. Results: The clinical measurement 3 months after extraction revealed a loss of bone width of 0.3 ± 0.5 mm in group A, 0.8 ± 0.7 mm in group B, and 0.1 ± 0.1 mm in group C. There was no significant difference in bone resorption in extraction sites among the groups (P > .05). However, the difference between group A and group C was borderline significant (P = .07). After 10 days, 31 grafts from group C and 30 grafts from group B remained vital. Conclusions: It seems that extraction technique affects alveolar bone resorption, regardless of whether the socket is treated with free gingival graft or bone graft. Further, the local application of gentamicin presented more vascular ingrowth in the blood clot and granulation tissue beneath the graft, thereby supplying better nourishment during the initial healing phase of the graft. Keywords: atraumatic extraction, collagen, gentamicin, socket seal surgery

Objective: To evaluate the changes in surface roughness of dental ceramics with various substances/ instruments and polishing methods during the course of repeated firings. Method and Materials: Three types of dental ceramic (IPS Classic, Empress Esthetic, and Empress 2 [all by Ivoclar Vivadent]) were used to form three groups, respectively. The samples from the first group were subjected to glaze, the second group to natural glaze, and the third group to mechanical polishing. As many as seven firings were performed on each sample, and surface roughness measurements of the samples were carried out at certain stages. Statistical evaluation was performed through repeated-measures ANOVA, and the Duncan test proved that the differences among the mean values were by no means a coincidence. Results: The interaction among the substrates, the method used, and the time was statistically significant (P < .05). Mechanical polishing significantly increased surface roughness (P < .05), and the greater number of firings significantly decreased the amount of surface roughness (P < .05). Conclusion: In terms of surface roughness, the best method available is the glaze method and the best material is IPS Classic. The mechanical polishing process generates rough surfaces. Repeated firings should be avoided as much as possible because they have a destructive effect on the glaze layer and deform the surface. Keywords: dental ceramic, polishing methods, repeated firings, surface roughness

Objectives: To investigate whether a stable bond could be obtained between resin-reinforced glassionomer cement and zirconia ceramic. Method and Materials: Sixty disk specimens of a dental ceramic (Cercon zirconia ceramic, Dentsply) were made and treated by airborne-particle abrasion. They were divided into three groups and bonded to two resin-reinforced glass-ionomer cements (RelyX Luting [3M ESPE] and Fuji Plus [GC]) and one resin cement (Panavia F, Kuraray) as a control group. All bonded specimens of each group (n = 20) were stored in distilled water (37°C) for 24 hours, and half were additionally aged by thermocycling (20,000 times). Shear bond strength test was performed to measure the bond strength. Statistical analyses were performed using one-way ANOVA and paired t test with α = .05. The interfacial morphology of debonded specimens was observed by using a scanning electron microscope, and the mode of bonding fracture was evaluated. Results: The initial shear bond strength (in 24 hours) of the two resin-reinforced glass-ionomer cements to zirconia ceramic was 17.33 ± 3.53 MPa and 16.68 ± 2.76 MPa, and it dropped significantly to 7.62 ± 2.17 MPa and 4.65 ± 2.02 MPa after thermocycling. In the control group, the initial shear bond strength was 26.25 ± 5.61 MPa, and there was no obvious decrease after thermocycling. The bonding failure of resin-reinforced glass-ionomer cements was mostly adhesive failure between cement and ceramic. Conclusion: Resin-reinforced glass-ionomer cement could not offer a stable bond to abraded zirconia ceramic after thermocycling, and there was no durable chemical or mechanical bond between resin-reinforced glass-ionomer cement and zirconia ceramic. Keywords: bonding fractured mode, resin-reinforced glass-ionomer cement, scanning electron microscope, shear bond strength, zirconia ceramic

Objective: To assess the influence of air-polishing devices and various abrasives on flat root surfaces. Method and Materials: A total of 168 natural teeth were embedded in polyurethane resin and treated with airborne-particle abrasion using two air-polishing devices (Prophyflex 3, KaVo; EMS Handy, EMS), four abrasives (Airflow powder, EMS; Cleaning powder, KaVo; ClinPro powder, 3M ESPE; and ProphyPearls, KaVo), and three treatment times (5, 10, and 20 seconds). Defects were quantified using a confocal laser scanning microscope. Results: The Prophyflex device clearly generated deeper substance defects compared to the EMS device, regardless of abrasive used (Kruskal-Wallis, P = .004). ProphyPearls abrasive caused the deepest defects with both devices. ClinPro powder produced the least amount of defects. Defect depths increased significantly for all abrasives with increasing treatment times (Kruskal-Wallis, P = .01), and all abrasives except ClinPro powder caused substantial volume loss. Conclusion: The abrasiveness of air-polishing powders differs depending on the polishing device used. ProphyPearls caused more substance loss than ClinPro powder. Keywords: airborne-particle abrasion, glycine powder, NaHCO3, ProphyPearls, root defects, root dentin