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Reestablishing biologic width with forced eruption.

Maintenance of gingival health is one of the keys for the longevity of teeth, as well as for the longevity of restorations. In this context, the biologic width functions as a barrier against the entrance of microorganisms into the internal medium of the periodontal ligament and into the gingival and osseous connective tissue. This clinical case describes a technique to reestablish the biologic width of a central incisor using forced extrusion and done without post-treatment corrective surgery.

Adult↗

Two-year clinical effectiveness of a resin-modified glass-ionomer adhesive.

PURPOSE: To evaluate the clinical effectiveness of a resin-modified glass-ionomer adhesive FujiBond LC (GC) in non-carious Class V cervical lesions. METHODS: 28 patients and 52 abrasion-erosion lesions were restored using FujiBond LC and a microfilled resin composite in a cavity design with the adjacent enamel margins beveled. Clinical parameters as retention, marginal integrity, clinical microleakage, caries recurrence, esthetics, gingival response, tooth vitality and post-operative sensitivity were evaluated at 6 months, 1 and 2 years. RESULTS: A 100% retention rate was recorded after 2 years of clinical service. However, only 15% of the restorations showed a perfect marginal adaptation. All marginal defects were small, either located at the incisal or at the cervical margin. The percentage of small marginal defects was obviously higher at the incisal enamel margin than at the cervical dentin margin. At the 2-year recall, half of the restorations exhibited a superficial, localized discoloration at the restoration margin, however none of the restorations showed deep, generalized discoloration. Remaining criteria of clinical effectiveness were rated as excellent.

Adult↗

Five-year double-blind randomized clinical evaluation of a resin-modified glass ionomer and a polyacid-modified resin in noncarious cervical lesions.

PURPOSE: The aim of this double-blind randomized study was to compare the clinical performance of a resin-modified glass ionomer (Vitremer, 3M) and a polyacid-modified resin (Dyract, Dentsply DeTrey) in noncarious Class V restorations after 5 years. MATERIALS AND METHODS: Twelve patients, having at least one pair of equal-sized noncarious cervical lesions under occlusion and a mean age of 40 years (range 19 to 63 years; median 41), were enrolled in this study. A total of 32 restorations (16 with each material) were placed according to the manufacturers' instructions by two calibrated operators. Two other independent examiners evaluated the restorations at baseline and after 5 years according to the USPHS criteria. The assessment criteria were: retention, anatomical form, marginal adaptation and marginal discoloration, color match, surface texture, and secondary caries. Statistical analysis was conducted using Fisher's exact test (alpha = 0.05). RESULTS: No secondary caries was detected with either material. The retention rate for Vitremer (93%) and for Dyract (78.5%) did not differ significantly (p > 0.05). Regarding anatomical form, only two restorations of each material were recorded as bravo. In terms of marginal adaptation, 38.5% of Dyract restorations were rated alpha and 61.5% bravo, while 84.6% of Vitremer restorations were rated alpha and only 15.4% bravo (p < 0.05). For marginal discoloration, 18.2% of Dyract restorations and 84.6% of Vitremer restorations were rated alpha, with the remaining rated bravo. 86% of Vitremer restorations were rated as bravo and 23% alpha for both surface texture and color match. All Dyract restorations were classified as alpha regarding surface texture, and only two Dyract restorations (18.2%) were classified as bravo in the color match item. CONCLUSION: The marginal adaptation of the RMGIC (Vitremer) was significantly better, the marginal discoloration lower, and the retention rate higher (though not significantly) than that of the PMRC (Dyract) after 5 years in situ. Dyract performed better in terms of surface texture and color match in noncarious Class V restorations after 5 years.

Adult↗

Developing natural aesthetics with direct composite restorations.

Contemporary direct restorations have significantly evolved since their initial development, allowing clinicians to develop natural-looking restorations. Composite resins can be applied for restoration of cavities, anterior tooth reconstruction, core preparation for crowns, splinting, provisionalization, placement of orthodontic brackets, and cementation. The development of hybrid and microfilled composite materials has further improved the clinician's ability to deliver minimally invasive treatment options. This article demonstrates a stratification process in the interproximal and incisal edge reconstruction of maxillary right and left central incisors using a small-particle hybrid composite resin to develop an optimal aesthetic result.

Adult↗

The nano-hardness and elastic modulus of carious and sound primary canine dentin.

This study measured the nanohardness and elastic modulus- of carious and sound primary canine dentin and compared the values obtained under the lesion and in sound regions of incisal, center and cervical areas, and outer, middle and inner layers. Six extracted or exfoliated primary canines (three with dentin caries on both proximal surfaces and three sound teeth) were mesiodistally sectioned parallel to the long axis of the tooth and polished. The hardness (H), plastic hardness (PH) and Young's modulus (Y) were measured by a nano-indentation tester. Ten indentations at intervals of 10 microm on all regions, areas and layers were made using a load of 1 gf for one second. All indentations were observed using a microscope attached to the tester. All data were statistically analyzed using ANOVA and Scheffe's test at p < 0.05. For sound teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in all areas. The H, PH and Y values of the cervical area were significantly lower than the incisal area in almost all of the outer, middle and inner layers. For carious teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in the center area. For the center area, the H, PH and Y values under the lesion were significantly lower than sound teeth in the outer and middle layers. Dentin under the lesion, near the pulp and cervical areas showed significantly lower nanohardness and elasticity.

Analysis of Variance↗

Bonding to cervical sclerotic dentin: effect of acid etching time.

PURPOSE: The aim of this in vitro study was to evaluate the microtensile bond strengths (MTBS) of two total-etch one-bottle adhesive systems to natural cervical lesions with 2 different etching times (15 s vs 30 s). MATERIALS AND METHODS: Thirty-two human canines and premolars with saucer-shaped noncarious cervical defects were cleaned and randomly assigned to 4 groups. The adhesive systems - Single Bond (SB; 3M ESPE) or OptiBond Solo Plus (OP; Kerr) - were applied on cervical dentin after acid etching with the proprietary acid gel (35% or 37.5% phosphoric acid) for 15 s (manufacturer's instruction) or for 30 s. The respective hybrid composite was inserted in three increments and light cured. After 24 h water storage, the specimens were cut perpendicularly with a low-speed diamond saw (Isomet) to obtain slices with a cross section of ca 0.8 mm. After that, the slices were trimmed with a diamond bur to obtain a surface area of 0.7 +/- 0.05 mm2 (n = 12). MTBS was measured in a Bencor device with an Instron machine at a crosshead speed of 0.5 mm/min. The data were subjected to two-way ANOVA and Tukey's LSD post-hoc test (p < 0.05). RESULTS: MTBS are given in MPa (mean +/- SD), where means with the same superscript letter are not statistically different at p < 0.05: OP15 = 30.9 +/- 8.8ab, SB15 = 25.6 +/- 9.6bc, OP30 = 19.0 +/- 4.8c, SB30 = 35.9 +/- 11.0a. When data were pooled for "adhesive system", SB resulted in statistically higher bond strengths than OP (p < 0.043). "Acid etching time" had no significant effect (p < 0.766), but the interaction of the two main factors yielded significant differences (p < 0.0001). Extending etching time to 30 s resulted in a more predictable bond to noncarious cervical sclerotic dentin with SB, but resulted in lower MTBS with OP. CONCLUSION: Composite bonding to cervical sclerotic noncarious dentin may depend on acid demineralization capacity and bonding system. Knowing the etching demineralization rates of the commercially available acid etching seems to be an important factor for selecting the best acid-etching time of cervical sclerotic dentin.

Acid Etching, Dental↗

Durability of three simplified adhesive systems in Class V non-carious cervical dentin lesions.

PURPOSE: To investigate the durability of three simplified systems in Class V non-carious abrasion/erosion lesions. METHODS: 144 non-carious cervical dentin lesions were restored either with Clearfil Liner Bond 2, a 2-step self-etching primer (n = 46), One Coat Bond, a one bottle total-etch system applied with one coat (n = 46), or Prompt-L-Pop, a 1-step self-etching primer ("all-in-one") (n = 52), in 90 individuals. Ninety-eight of the lesions showed sclerotic dentin and 46 were non-sclerotic. Sixty-one were slightly roughened with a diamond bur before conditioning. The restorations were evaluated every 6 months during a 2-year period with slightly modified USPHS criteria. RESULTS: All except three restorations were evaluated over 2 years. The cumulative loss rates for Clearfil Liner Bond 2, One Coat Bond and Prompt-L-Pop were at 6 months: 4.3, 2.2 and 3.9%, at 18 months: 4.3, 10.9 and 15.4% and at 24 months: 8.7, 13.0 and 21.2%, respectively. The cumulative loss rates of the materials in sclerotic lesions (15.7%) versus non-sclerotic lesions (14.0%) were not significanty different. Restorations placed with a diamond bur-roughened lesions showed a loss rate of 14.5%, while for the non-roughened lesions the frequency was 14.8%.

Aged↗

A randomized, controlled trial evaluating the three-year clinical effectiveness of two etch & rinse adhesives in cervical lesions.

A three-year randomized, controlled prospective study evaluated the clinical performance of two three-step etch & rinse adhesives (OptiBond FL, Kerr: O-FL; PermaQuick, Ultradent: PMQ) in Class V cervical erosion-abrasion lesions. The latter adhesive was also tested with two restorative composites with contrasting stiffness in order to evaluate the effect composite stiffness might have on the clinical longevity of cervical restorations. A total of 150 lesions were randomly restored in pairs of the three adhesive/composite combinations (PMQ combined with Amelogen Hybrid: PMQ/A-Hy, Ultradent; PMQ combined with Amelogen Microfill: PMQ/A-Mi, Ultradent; O-FL combined with Prodigy: O-FLJPro, Kerr) per patient and evaluated at baseline, after six months, one year, two years and three years of clinical service. After three years, the retention rate was 100% for O-FL/Pro and 98% for both PMQ/A-Hy and PMQ/A-Mi, thereby, satisfying the "full acceptance" guidelines specified by the American Dental Association. A pairwise comparison showed no significant difference in adhesive performance between restorations made using the microfilled and hybrid composite for any evaluation criteria (p>0.05).

Chi-Square Distribution↗

Partial ceramic crowns: influence of preparation design and luting material on internal adaptation.

The influence of three different cavity preparations on the marginal integrity of partial ceramic crowns (PCC) luted with four different luting systems was investigated in this in vitro study. PCC preparations were performed in 144 extracted human molars using one of the following preparation designs (n=48/preparation): A--Coverage of functional cusps/butt joint preparation; B--horizontal reduction of functional cusps and C--complete reduction of functional cusps/butt joint preparation. Non-functional cusps were not covered; mesial and distal proximal boxes were extended 1 mm below the cemento-enamel-junction. PCC were fabricated from Vita Mark II ceramic (Vita) with a Cerec 3 Unit (Sirona) and adhesively luted to the cavities using the following luting systems: (VL) Variolink II/Excite (Vivadent), (PA) Panavia F/ED Primer (Kuraray), (DY) Dyract/Prime & Bond NT (DeTrey/Dentsply) and (FU) Fuji Plus/GC Cavity Conditioner (GC). Samples were simultaneously exposed to thermocycling and mechanical loading (TC: 5000x8-55 degrees C, 30 seconds/cycle; ML: 500000x72.5N, 1.6Hz). Marginal adaptation was assessed by evaluating dye penetration on multiple sections by relating the actual penetration distance to the maximal length of the corresponding cavity wall (100%). Ceramic- and tooth-luting material interfaces were evaluated separately. The data were statistically analyzed with the Mann Whitney U-test and Wilcoxon Rank Sumtest. In general, no significant differences could be found between preparations A, B and C. The combination of preparation C and luting material PA showed a tendency for the lowest dye penetration values, especially within dentin (30%). Significant differences could be determined between luting materials: Composite luting materials PA (0%) and VL (1%) revealed less dye penetration than the compomer DY (6%) and resin-modified glass ionomer cement (RMGIC) FU (26%); use of RMGIC caused fractures of the restorations. The dentin/luting material interface showed the highest penetration values, ranging from 17% to 100%. In conclusion, with adhesively bonded partial ceramic crowns, the choice of luting material proved to be more relevant than preparation design under the limitations of this study. Margins below the cemento-enamel junction reveal significant loss of adhesion in spite of subsequent application of adhesive luting techniques. RMGIC cannot be recommended as a luting material for feldspathic PCC.

Acrylic Resins↗

Demineralization inhibition of direct tooth-colored restorative materials.

This study compared the demineralization inhibition properties of fluoride releasing tooth-colored restorative materials. Materials evaluated included a giomer (Reactmer, Shofu [RM]), a conventional glass ionomer (Fuji II, GC [FJ]), a resin modified glass ionomer (Fuji II LC, GC [FL]) and a compomer (Dyract AP, Dentsply [DY]). A non-fluoride releasing composite (Spectrum TPH, Dentsply [SP]) was used for comparison. Class V preparations on buccal and palatal/lingual were made at the CEJ of 75 freshly extracted molars. The teeth were randomly divided into five groups of 15 and restored with the various materials. The occlusal half of each restoration was in enamel, while the gingival half was in dentin. The restored teeth were stored in distilled water at 37 degrees C for two weeks and subjected to artificial caries challenge (18 hours demineralization [pH 5.0] followed by six hours of remineralization [pH 7.0]) for three days. Sections of 130 +/- 20 microm were examined with a polarized light microscope, and outer lesion depth [OLD] and wall area [WA] lesion/inhibition measurements were made using image analysis software. All data were subjected to statistical analyses at 0.05 significance level. For the various materials, OLD ranged from 54.55 to 65.86 microm and 124.68 to 145.97 microm in enamel and dentin, respectively. WA ranged from -2356.13 to 1398.20 microm2 and -3011.73 to 5095.80 microm2 (positive values indicate wall inhibition, negative values indicate wall lesion) in enamel and dentin, respectively. Results of ANOVA/Scheffe's post-hoc test (p<0.05) were as follows: Enamel OLD--no significant difference between materials; Dentin OLD--SP > FJ, FL & RM; Enamel WA inhibition--FJ, FL & RM > DY & SP and Dentin WA inhibition--FJ > FL > RM > DY > SP. The demineralization inhibition effect of giomers, conventional and resin-modified glass ionomer cements appear to be more evident at the margins of restorations.

Cariostatic Agents↗

Talon cusp: an overview with case reports of 3 clinical variants.

Talon cusp is a dental anomaly, which is present as an accessory cusp and is seen both in the deciduous and permanent dentition. It may occur unilaterally or bilaterally and has been reported mostly in maxillary teeth, with a few cases occurring in the mandible. Talon cusp is usually asymptomatic; however, there are many clinical problems associated with it. Talon cusp is clinically manifested in three forms: talon, semi-talon and trace talon. In this article, we present four case reports of talon cusp with an overview of different clinical variants of talon cusp, classification, etiopathogenesis, associated syndromes, clinical problems, and treatment modalities.

Adolescent↗

Microleakage of compomer restorations in primary teeth after preparation with bur or air abrasion.

This study compared the degree of marginal leakage of a compomer in Class V cavities of human primary molars prepared by a conventional dental bur and air abrasion with or without acid etching. Fifty-six non-carious extracted primary molars were randomly divided into four groups (n=14) to be prepared by four techniques: Group-1: Bur followed by acid etching: Class V cavity preparations were placed on the buccal surfaces of each tooth using a high-speed handpiece. The preparations were 1.5-mm deep, 3-mm long and 2-mm wide, with the occlusal margin in enamel and the cervical margin extending 0.5 mm below the cementoenamel junction. The preparations were acid etched with 37% phosphoric acid starting at the enamel margins for 30 seconds and rinsed with water for 20 seconds. The preparations were then restored with Compoglass F. 2-Group 2: Bur: The preparations and the treatment procedures were the same as in Group 1, with the exception of 37% phosphoric acid application. Group 3: Air abrasion followed by acid etching: Class V cavity preparations were placed on the buccal surfaces of each tooth using a handpiece of an air-abrasive system (PrepStart, Danville Engineering). The system was supplied with dry compressed air at 80 psi. In all tests, the air-abrasion system was operated with an 80 degrees-angle handpiece tip and 50-mm aluminum oxide particles. A tip with a 0.38-mm inner diameter was used at a 2-mm distance. The treatment procedures were the same as in Groups 1 and 2. Group 4: Air abrasion: The preparations and treatment procedures were the same as in Group 3, with the exception of 37% phosphoric acid. After finishing the restorations, the teeth were stored in distilled water at 37 degrees C for 24 hours. The samples were thermocycled for 500 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds. The samples were then immersed in 0.5 percent basic fuchsin dye for 24 hours at 37 degrees C. The surface-adhered dye was then rinsed in tap water and the teeth were embedded in a chemically-activated acrylic resin and bisected longitudinally in a mesiodistal direction with a low speed diamond disk. Each section was examined under a stereomicroscope (Nikon, Tokyo, Japan) at 20x magnification. The data were analyzed statistically by Kruskal-Wallis analysis of variance to determine any statistical significant differences in microleakage scores among the groups at a p-value of 0.05. Also, the enamel versus cementum-dentin microleakage scores of each group were compared using z-test at the 0.05 significance level. There was no statistically significant difference among the groups (p>0.05), but a statistical difference between enamel and cementum-dentin surfaces was evaluated (p<0.05).

Acid Etching, Dental↗

Clinical performance of a self-etching adhesive at 18 months.

PURPOSE: To test the null hypothesis that beveling and/or etching enamel would not affect the 18-month clinical performance of the self-etching adhesive Clearfil SE Bond (CSEB) in noncarious cervical lesions (NCCL). METHODS: With Institutional Review Board approval, 34 patients were enrolled in this study. A total of 120 NCCL was selected and assigned to four groups: (1) CSEB was applied without any cavity preparation; (2) CSEB was applied after beveling enamel; (3) CSEB was applied after etching enamel for 15 seconds with 35% phosphoric acid; (4) CSEB was applied after beveling and etching enamel. A microfilled composite resin was used for all restorations. RESULTS: At 6 months after initial placement, 120 restorations (a 100% recall rate) were evaluated. At 18 months, 87 restorations (a 72.5% recall rate) were available for evaluation. A survival rate of 100% was measured for all groups at both 6 and 18 months. Sensitivity to air decreased significantly only for Group 3 (no bevel+acid etch) from baseline to 18 months without statistical changes from 6 months to 18 months. None of the other parameters resulted in significant differences for any of the four groups. However, when data were pooled, both the overall marginal discoloration and the overall marginal adaptation were significantly worse at 18 months than at baseline, while sensitivity to air decreased significantly from baseline to 18 months. The 18-month survival rate of the self-etching adhesive Clearfil SE Bond was not improved by enamel bevel or by enamel etching. Both overall marginal adaptation and overall marginal discoloration were worse at 18 months than at baseline. .

Acid Etching, Dental↗

Shear bond strength of tooth-colored indirect restorations bonded to coronal and cervical enamel.

This study evaluated the shear bond strength of resin inlays bonded with resin cement to cervical and mid-coronal enamel. Two regions of enamel, cervical and mid-coronal, were chosen from the buccal surface of extracted molars. Composite "inlays" (Estenia, Kuraray Medical Inc) were fabricated indirectly and cemented with a dual-cured resin cement (Panavia Fluoro Cement II, Kuraray Medical Inc). The resin cement was cured with or without light irradiation for 30 seconds. After 24-hours or one-week's storage in 37 degrees C water, the bonded inlays were subjected to a microshear bond test, whereby a shear force was applied to the inlays at a crosshead speed of 1 mm/minute. The data were statistically analyzed using ANOVA and Fisher's PLSD test, with significance defined as p<0.05. Observations using confocal laser scanning microscopy were also performed after debonding the specimens. The light-cure method showed significantly higher bond strengths to both enamel regions compared with self-cure, especially at 24 hours (p<0.05). However, bond strength of the self-cured resin cement significantly improved after one week's storage (p<0.05; cervical enamel: p=0.022, midcoronal enamel: p=0.0024). The cervical enamel showed significantly lower bonding than midcoronal enamel (p<0.05), except for the self-cured specimens at 24 hours. Light curing of resin cement is a better choice than self-curing for luting of indirect restorations. The bond strength of indirect restorations to cervical enamel was lower than mid-coronal enamel.

Composite Resins↗

Three-dimensional finite element analysis of stress in the periodontium.

The aim of this study is to calculate the stress produced in the periodontium at different bone levels under occlusal load. Four finite element models of maxillary incisors were designed consisting of the tooth, pulp, periodontal ligament and alveolar bone at various levels of bone height (25%, 50% and 75%). An occlusal load of 24 kg at an angle of 50 degrees to the long axis of the tooth was applied on the palatal surface, at the level of the middle third of the crown. All the models were assumed to be isotropic, linear and elastic and the analysis was performed on a Pentium IV computer using the NISA II Display III software. The results showed that maximum stress in the tooth was seen at the cervical region and to a greater extent at the apex for all the models. In periodontal ligament, maximum stress was seen at the alveolar crest in models with normal alveolar bone height and with reducing alveolar bone height maximum stress was at the apex. There was no significant stress distribution in alveolar bone, while no stress was seen on the pulp. The results of the study demonstrated a significant increase in stress concentration at the apex with loss of alveolar bone height.

Alveolar Process↗

Toothbrush abrasions and noncarious cervical lesions: evolving concepts.

Toothbrush abrasion at the cervical areas of teeth is generally thought to be a result of frequent or forceful toothbrushing, faulty or vigorous technique, filament stiffness or design, dominant hand dexterity, or abrasive dentifrices. However, a review of the evidence-based literature cannot conclusively establish any one factor as the primary etiology of cervical abrasions because of inherent methodological limitations and conflicting results. Rather, a variety of factors related to toothbrushing may act in concert with dental erosion and, possibly, occlusal loading in the creation of noncarious cervical lesions. Individual variation also may make some individuals more susceptible to development and may modify the progression of those lesions. Individual variations may involve oral and dental anatomy, periodontal status or phenotype, and periodontal disease history and treatment. Further research is needed to clearly assess the interaction of all those factors in the development of cervical lesions. Therefore, awareness of a multifactorial etiology in noncarious cervical lesions may help the clinician to formulate an appropriate treatment plan for the patient.

Acids↗