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To determine the effectiveness of different pulse durations (PD) and the water/air (W/A) cooling ratio of the Er:YAG 2940 nm laser that are required for debonding porcelain laminate veneers (PLV), by investigation of the needed time for PLV debonding (DT) and the changes in dental pulp temperature.Thirty-six extracted noncarious human maxillary premolars were prepared for receiving PLV. Samples were randomly assigned to six different groups, based on PD and the W/A ratio: Groups A (50 µs, 1:1), B (50 µs, 3:3), C (100 µs, 1:1), D (100 µs, 3:3), E (300 µs, 1:1), and F (300 µs, 3:3). Veneers were debonded using laser irradiation by the same parameters (270 mJ, 15 Hz) with noncontact application mode.All 36 veneers were debonded. Samples of the 50 and 100 µs PDs showed significantly shorter DT (7.4-17 s) than that of the 300 µs which showed significantly the longest DT (104 s) among all other groups (p .001). However, the highest elevation of pulp temperature was observed in Group E (300 µs, 1:1) which reached (3.4°C).Using the 50 or 100 µs PD of the Er:YAG laser was more efficient than 300 µs in reducing DT of PLVs with minimal change in pulp temperature. W/A cooling ratio had minimal influence on the DT of PLV.

Objective The purpose of this clinical report was to describe the detection of fluorescent resin residue after orthodontic bracket debonding with two UV light devices and analyze the surface morphology of enamel after 1 year. Clinical considerations A 22-year-old woman had orthodontic brackets removed by a previous dentist; however, resin residue was left on the enamel of the maxillary teeth. After confirming the fluorescent property of the resin, different protocols were used for each half of the maxillary arch. The first method, a black light lens was attached to a light-curing device to detect resin fluorescence, followed by polishing with silicone rubber tips. The second method used a light emitting diode light system attached to and activated by a high-speed handpiece, followed by polishing with discs. Both methods were completed with diamond polishing paste applied with felt discs. Polyvinyl siloxane impressions were made initially, after residue removal, after finishing and after polishing for morphologic analysis. The results were evaluated with photographs and the scanning electron microscope images made of resin casts from the impressions. A follow-up was made after 1 year. Conclusions Both methods yielded a satisfactory clinical outcome, with a smooth surface, acceptable surface gloss and minimal tooth wear. The use of a UV device that excites fluorescence is recommended for the controlled removal of resin residue on enamel. Clinical significance The controlled removal of resin residue from enamel after orthodontic treatment is challenging but can be improved with auxiliary methods for detecting resin residues. This clinical report describes two types of devices that excite fluorescent resins in a more rapid and precise technique to guide the practitioner in the controlled removal of residual resin on teeth.

BACKGROUND/AIM Accurate removal of composite bonded titanium trauma splints (TTS) can be challenging. The aim of this study was to evaluate a Fluorescence-aided Identification Technique (FIT) compared with a conventional light source (CT) for removal of trauma splints regarding loss of tooth substance, residual composite, and time taken. MATERIALS AND METHODS Twenty maxillary models with six bovine teeth (13 - 23) were fabricated. An optical three-dimensional impression was taken and a TTS was applied from 12 to 22 with two bonding sites on every tooth under standardized conditions using an etch-and-rinse adhesive and resin composite. Two operators removed 10 splints each (5x FIT and 5x CT). For FIT, a 405 nm light-emitting headlamp was used. Time was recorded. A post-operative scan was superimposed on the pre-operative scan using OraCheck software. A qualitative and quantitative analysis of tooth defects and composite remnants was performed by two operators and statistically analyzed. RESULTS Compared with the CT, FIT led to significantly fewer and smaller enamel defects (mean volume: -0.04 mm3 vs -0.33 mm3 ) (P

Objective To determine the efficiency of debonding porcelain laminate veneers (PLV) by using several laser parameters and two different application modes of Er:YAG laser [contact (CM) and non-contact (NCM)], by verification of the consumed PLV debonding time and the changes in dental pulp temperature. Materials and methods Forty extracted non-carious human maxillary premolars were prepared for receiving PLV. Sixteen of them were divided into two groups, each of them comprised eight samples based on the application mode; group A with NCM, and group B with CM. Veneers of both groups were debonded by the same laser parameters (360 mJ, 15 Hz) during loading of a 15 N force on specially fabricated veneer cervical margins. The primary results showed that the NCM was more efficient, thus, additional groups (C, D, and E) of the same mode and number of samples were tested with different laser parameters of energy and frequency; group C (400 mJ, 10 Hz), group D (270 mJ, 15 Hz), group E (300 mJ, 10 Hz). The failure mode was determined and classified for the debonded samples of all groups. Results All veneers were debonded and samples of the NCM group had considerably lower debonding time (12.6 seconds) than the CM samples (96.3 seconds), however, higher changes of temperature in NCM (4.2°C) than in CM were observed (2.9°C). The failure mode of samples was either type 1 or 3. Conclusion Er:YAG laser is an effective tool in debonding PLVs. The NCM application mode was more efficient in reducing debonding time than CM application mode but with a higher change in pulp temperature. Clinical Significance Investigating the efficacy of Er:YAG laser as a non-invasive particle technique for debonding of failed or malpositioned of porcelain laminated veneers

Structured AbstractObjective To evaluate the effect of organic gel solvents (70% acetone and 90% ethanol) and ultrasound in the removal of metallic brackets. Materials and Methods Metallic brackets were bonded with light-cured orthodontic composite (Transbond XT) in 120 human bicuspids and divided into 6 groups for the enamel etch-and-rinse adhesive system (XT) and 6 groups to self-etching system (SEPT) according to pretreatment to removal test: control, 70% acetone, 90% ethanol, ultrasound, 70% acetone+ultrasound, and 90% ethanol+ultrasound. The brackets were subjected to removal by shear testing and Adhesive Remnant Index (ARI) evaluation. Some specimens were prepared and its adhesive interface and etching ability observed by scanning electron microscopy (SEM). Results Only the factor ‘ultrasound’ and its interaction with ‘adhesive’ were detected as a source of variance, with the SEPT/ultrasound showing the lowest shear strength than the other groups. Regardless the factor ‘ultrasound’, XT showed a higher ARI than SEPT; however, when the solvents were used, no differences were detected between XT and SEPT. Conclusion The organic solvents were not effective in reducing shear bond strength. The etch-and-rinse adhesive system showed a higher and more favorable ARI score than the self-etching primer. The behavior of the organic solvents on ARI showed to be better when associated with the self-etching primer. The ultrasound was effective in reducing the shear bond strength of the self-etching adhesive system but not in affecting the ARI of the adhesive systems.

Introduction\ud \ud Professional regulatory bodies in the UK and Europe state that dental graduates should be able to manage orthodontic emergency patients. Therefore, the aim of this study was to explore dental student experiences of treating orthodontic emergencies within a teaching institution.\ud Materials and method\ud \ud This study was designed as a single-centre evaluation of teaching based in a UK university orthodontic department. The participants were fourth-year dental students who treated orthodontic emergency patients under clinical supervision as part of the undergraduate curriculum. Student logbook entries for one academic year detailing the types of emergencies treated and structured, reflective commentaries for each procedure were analysed using thematic analysis methods. The total numbers and types of orthodontic emergencies treated by students were presented. Overall, self-reported student confidence in managing orthodontic emergencies was calculated. Themes, which represented student reflections, were identified.\ud Results\ud \ud Seventy-two students participated in the study. Overall, 69% of students stated they were confident in managing orthodontic emergencies. Students treated a range of emergencies, of which the most frequent was debonded brackets (38%). Reflections from student commentaries were housed under a primary theme of building procedural confidence. Three subthemes were identified: (i) theory-practice integration; (ii) expanding clinical experience; and (iii) importance of a supportive clinical learning environment.\ud Conclusion\ud \ud The majority of dental students were confident in managing orthodontic emergencies. Theoretical knowledge supplemented by exposure to a range of clinical problems within a supported learning environment made students feel more confident.

Summary The purpose of this in vivo study was to compare the morphology of the enamel surfaces before bracket bonding and 6 and 12 months after debonding. Replicas of thirty-two maxillary second premolars of 16 volunteers were made before bracket bonding (T0), after debonding (T1), 6 months (T2), and 12 months (T3) later. Scanning electron microscope (SEM) images of the labial enamel surfaces were taken at T0, T1, T2, and T3 at increasing magnifications and analyzed according to the enamel damage index EDI. Data evaluation by using Friedman test followed by Wilcoxon signed ranks test with Bonferroni adjustment did not reveal statistically significant differences in the mean EDI at T0, T2, and T3, whereas the mean EDI at T1 was significantly higher than at T0, T2, and T3 (p

Jeon H., Lee S. J., Kim T. W., Donatelli R. E. Three-dimensional analysis of lip and perioral soft tissue changes after debonding of labial brackets Orthod Craniofac Res 2013; 16: 65–74. © 2012 John Wiley & Sons A/S Structured Abstract Objectives – To evaluate the possible soft tissue changes after debonding of labial brackets using three-dimensional (3D) images acquired by a laser scanner. Methods – On the same day, 3D facial scans were taken immediately before debonding (T1) and immediately after debonding (T2) from 53 patients, and follow-up scans were taken 3 months after debonding (T3) from 31 patients. To compare the scans, superimpositions were performed and shell-to-shell deviations were used for quantitative analysis. Results – Shell-to-shell deviation map showing warm colors in lip and perioral tissue represented the retrusion of soft tissue after bracket removal. Soft tissue retrusion was significant for all landmarks immediately after debonding (T1–T2) and 3 months after debonding (T1–T3). Gender, bracket type, and the lip thickness variables did not show a clinically significant influence on the amount of soft tissue retrusion at the T1–T3 period. Lip corners and vermilion borders were significantly retruded at the T1–T3 period more than other perioral areas. A negative linear relationship was found in the amount of soft tissue retrusion immediately after debonding (T1–T2) and from debonding to 3 months after debonding (T2–T3). Conclusion – Three-dimensional imaging showed significant changes in lip and perioral soft tissue after debonding of labial brackets. Clinically significant changes, approximately 2 mm of retrusion, occurred in the mouth corners bilaterally. Vermilion border landmarks also demonstrated significant changes in more than 1 mm. However, it was not possible to predict the soft tissue changes. A wide range of individual variability in the response to treatment and soft tissue adaptation was noted.

The effects of casein phosphopeptide amorphous calcium fluoride phosphate (CPP-ACFP) paste vs. control paste on the remineralization of white spot caries lesions and on plaque composition were tested in a double-blind prospective randomized clinical trial. Fifty-four orthodontic patients, with multiple white spot lesions observed upon the removal of fixed appliances, were followed up for 3 months. Subjects were included and randomly assigned to either CPP-ACFP paste or control paste, for use supplementary to their normal oral hygiene. Caries regression was assessed on quantitative light-induced fluorescence (QLF) images captured directly after debonding and 6 and 12 wk thereafter. The total counts and proportions of aciduric bacteria, Streptococcus mutans, and Lactobacillus spp. were measured in plaque samples obtained just before debonding, and 6 and 12 wk afterwards. A significant decrease in fluorescence loss was found with respect to baseline for both groups and no difference was found between groups. The size of the lesion area did not change significantly over time or between the groups. The percentages of aciduric bacteria and of S. mutans decreased from 47.4 to 38.1% and from 9.6 to 6.6%, respectively. No differences were found between groups. We observed no clinical advantage for use of the CPP-ACFP paste supplementary to normal oral hygiene over the time span of 12 wk.

Orthodontic treatment with fixed appliances is considered a risk factor for the development of white spot caries lesions (WSL). Traditionally, brackets are bonded to the buccal surfaces. Lingual brackets are developing rapidly and have become more readily available. Buccal surfaces are considered to be more caries prone than lingual surfaces. Furthermore, lingual brackets are shaped to fit the morphology of the teeth and seal almost the entire surface. In the present study we tested the hypothesis that lingual brackets result in a lower caries incidence than buccal brackets. We tested this hypothesis using a split-mouth design where subjects were allocated randomly to a group receiving either buccal or lingual brackets on the maxillary teeth and the alternative bracket type in the mandible. The results indicate that buccal surfaces are more prone to WSL development, especially when WSL existed before treatment. The number of WSL that developed or progressed on buccal surfaces was 4.8 times higher than the number of WSL that developed or progressed on lingual surfaces. When measured using quantitative light-induced fluorescence (QLF), the increase in integrated fluorescence loss was 10.6 times higher buccally than lingually. We conclude that lingual brackets make a difference when caries lesion incidence is concerned.

Aim To compare residual root-end filling material in apical root-end cavities following their removal with ultrasonic retrotips. Methodology Thirty single-rooted teeth were filled with Thermafil and AH Plus sealer. Root-ends were resected at 90°, 3 mm from the apex. Root-end cavities were prepared with diamond burs and ultrasonic retrotips and filled with one of three filling materials: group I: Retro-TC (calcium silicate-based cement), group II: IRM (Dentsply, Germany), group III: Vitrebond (3M ESPE, USA). After 30 days of storage, ultrasonic retrotips were used to remove materials from the root-end cavities. The ultrasonic application time was fixed at 60 s. Polyether impressions and replicas of the root-ends were made. Root apices and replicas were examined by one operator under a scanning electron microscope. Remnants of residual materials were evaluated using a four-level scoring system; fractures, smear layer and exposed dentinal tubules were also examined. Results Forty per cent of the specimens filled with Retro-TC revealed complete removal of the material with exposure of dentinal tubules, whilst 60% contained residual cement. Twenty per cent of specimens filled with IRM were completely devoid of material, whereas 80% had retained material. Ten per cent of specimens filled with Vitrebond retained a moderate amount of material whilst 90% had substantial retention of the material. Statistically significant differences were found (P

Aim To investigate and compare the displacement resistance of glass fibre reinforced composite (FRC) posts to root dentine after luting with different adhesive systems. Methodology A total of 32 noncarious extracted human mandibular premolars were prepared for post-cementation using the FRC Postec system (Ivoclar Vivadent, Schaan, Liechtenstein) and divided into four groups (n = 8). The posts in each group were luted with one or other of the following materials. Group 1: Variolink II/Excite DSC (etch-and-rinse, dual-curing), group 2: Clearfil Esthetic Cement/ED Primer II (self-etch, dual-curing), group 3: Multilink/Multilink Primer (self-etch, chemical-curing) and group 4: Multilink Sprint (self-adhesive, dual-curing). Specimens were sectioned to obtain slices with the post in the centre and with the root dentine overlaid by the autopolymerizing acrylic resin on each side. The displacement resistance was measured using a Universal Testing Machine at a crosshead speed of 0.5 mm min−1. The displacement resistance of the specimens were calculated and expressed in MPa. Data were analysed with one-way anova and post hoc Tukey’s test (P

Failed restorations diagnosed with salvageable and subsequently reusable metal substructures that demand their separation can be clinically challenging to undertake without the risk of damaging either the super- or substructures. This article describes a technique to safely separate them from each other in order for the respective substructure to be reused in the fabrication of a newly reconstructed restoration and for the existing restoration to be reused as a provisional where appropriately indicated.

summaryin vitro study reports on the cleaning effect of different soaps on the shear bond strength of various dentine-bonding agents. Human teeth were coated with provisional cements for 24 h or for 14 days. After removing the provisional cements with a scaler, the dentinal surface was cleaned with a cotton pellet and non-fluoridated flour of pumice and soap for 10 sec. Different dentine-bonding agents and a luting resin were bonded to the dentinal surface according to manufacturers'instructions with the bonding agent and the composite material being light-cured at the same time. The bonding agents were tested under intrapulpal pressure and with thermal cycling to imitate physiological conditions. Compared with cleaning the dentine with water and pumice, all soaps investigated in this study decreased the shear bond strength values of the tested dentine-bonding agents considerably.

Because there is no standard protocol for the removal of resin-based materials that retain semi-rigid trauma splints on teeth, iatrogenic enamel damage caused by various splint removal techniques has remained unknown. The purpose of this study was to evaluate the effect of five different resin removal techniques (H6/H7 scaler, ultrafine diamond bur, ultrasonic scaler, 16-blade tungsten carbide bur, and Sof-Lex disks) on the surface roughness of human enamel. Three-dimensional white-light interferometry, a non-contact profilometry technique, was used to obtain qualitative and quantitative measurements of surface roughness both at baseline and after finishing procedures. Statistical analysis using Friedman test and Wilcoxon signed ranks test showed that the roughest enamel surface was obtained after splint removal with the hand scaler (P < 0.05). Overall, the smoothest enamel surface was obtained after removal of resin with Sof-Lex disks and the 16-blade tungsten carbide bur (P < 0.05).

van der Sluis LWM, Wu MK, Wesselink PR. The evaluation of removal of calcium hydroxide paste from an artificial standardized groove in the apical root canal using different irrigation methodologies. International Endodontic Journal. Aim To evaluate the capacity to remove a calcium hydroxide (Ca(OH)2) paste from the root canal and to evaluate the efficacy of Ca(OH)2 removal during passive ultrasonic irrigation using either sodium hypochlorite (NaOCl) or water as an irrigant. Methodology Sixteen mandibular premolars were used. Each root was prepared to the apical foramen using GT instruments of size 30, 0.06 taper. Each root was split longitudinally. In one half of the root, a groove was cut in the canal wall 2‐6 mm from the apex which was then filled with a Ca(OH)2 paste. Subsequently the roots were reassembled. In group 1 (n ¼ 16), the teeth were ultrasonically irrigated using 50 mL 2.0% NaOCl as the irrigant. Group 2 (n ¼ 16) was treated in the same manner as group 1, but using 50 mL water in place of the NaOCl. In group 3 (n ¼ 16), the teeth were irrigated by syringe injection of 50 mL 2.0% NaOCl. The quantity of remaining Ca(OH)2 in the groove was scored and the data analysed with Kruskal‐Wallis and Mann‐Whitney tests. Results The difference in remaining Ca(OH)2 between all groups was statistically significant (P < 0.001). Group 1 had significantly lower scores than group 2 (P < 0.001) and group 3 (P ¼ 0.002), but there was no significant difference between groups 2 and 3 (P ¼ 0.765). Conclusions Passive ultrasonic irrigation with 2% NaOCl was more effective in removing Ca(OH)2 paste from artificial root canal grooves than syringe delivery of 2% NaOCl or water as irrigant.

Purpose: To evaluate the luting agents and retentive forces before and after mechanical stressing. Materials and Methods: Sample size N was 12 for each group, and 12 Cera-One closed-end gold cylinders were cemented with three types of luting cements (ImProv, UltraTemp, and TempBond). The force required to remove the gold cylinders from the abutments was determined with an MTS testing machine. After cleaning and recementing the cylinders, the samples were placed in the housings of an Alabama-type three-body wear machine and load of 110 N was applied to the gold cylinders at a frequency of 80 cycles/min for 50,000 cycles. Then each cylinder was pulled from its abutment and the force at which the failure occurred was recorded. The procedure was repeated with 300,000 cycles. Results: Statistical analysis arising from two-way ANOVA found that the forces required to remove the abutments were significantly different. The most retentive cement was ImProv. Before cyclic loading, on average, ImProv produced a retentive value 85% higher than that yielded by TempBond, and 25% higher than that of UltraTemp. The three cements were significantly different at each of the three cycle levels. Conclusions: These results might suggest TempBond luting agent as the material of choice for provisional cementation because it allows easier removal of the prosthesis and maintains enough retention to prevent loosening of the restoration. The clinical implication is that the effect of cyclic load on the strength of the cements is different, an important factor in selection of a cement. ImProv had the highest retentive value before and after the two cycles, and TempBond had the lowest. UltraTemp had the highest percentage of retentive value lost. TempBond had no significant loss under loading even though initially it was the weakest.

Aim To determine whether metal type, cement type and the use of ultrasonic vibration influence the amount of tensile force required to remove parallel-sided, prefabricated, metal posts from tooth roots. Methodology Ninety extracted canine teeth were sectioned horizontally 1-mm coronal to the labial cemento–enamel junction and embedded in acrylic blocks. Standardized post spaces were prepared with a ParaPost no. 5 (1.25 mm) drill to 10 mm and ParaPost XP no. 5 stainless steel and titanium posts were cemented using zinc phosphate, glass ionomer or composite resin cement. Sixty posts were subjected to 16 min of ultrasonic vibration whilst 30 stainless steel posts received no vibration. The force required for post removal was determined using a universal testing machine. Results were analysed using univariate anova. Results The univariate anova revealed no statistically significant differences between the groups at the P = 0.05 level. Conclusions In this in vitro experiment, metal type, cement type and ultrasonic vibration did not influence the force required to remove posts.

The bond strength of two heat-cured and four cold-cured soft lining materials was compared using a peeling test method before and after thermocycling. Tested soft lining materials were Molloplast B, Mollosil, Ufigel P, Ufigel C, Permaquick and Permaflex. Six specimens, 6.5 x 2 x 0.3 cm, for each group were prepared according to the manufacturers' instructions. Control groups were stored in a humidor for 24 h, whereas the others were thermocycled in a water bath between the 5 and 55 degrees C for 5000 cycles. Peel strength of samples were measured using an Instron Universal testing machine at a cross-head speed of 5 mm min-1. The types of failure were observed using an electron microscope. The highest peel bond strength values were calculated for Permaflex and Permaquick before and after thermocycling, respectively. Molloplast B, Mollosil, Ufigel P and Permaquick demonstrated an increase in peel strength after thermocycling, with Permaquick lining material having statistically significant increase. However, decrease in peel strength was observed for Ufigel C and Permaflex after thermocycling. Failure mode within the control groups was cohesive for Molloplast B, Permaquick and Permaflex, whereas adhesive for Ufigel P and Ufigel C. Mollosil demonstrated a mixed mode of failure for both thermocycled and control groups.

Background and Objective Conventional methods of residual composite removal after debonding orthodontic brackets involve the use of abrasives that damage the underlying enamel. The objective of this study was to determine whether infrared pulsed lasers are suitable for the removal of composite through selective laser ablation. Study Design/Materials and Methods Pulsed CO2 and Er:YAG lasers were evaluated for their ability to selectively ablate orthodontic composites. Optical emission spectra of the luminous plasma produced during composite and enamel ablation were acquired to differentiate between enamel and composite ablation to minimize accidental removal of enamel. Results TEA CO2 laser pulses at a wavelength of 10.6 μm were best suited for the selective ablation of composite. Spectral analysis of plume emission identified several calcium emission lines that can potentially be used to distinguish between enamel and composite ablation. Conclusion TEA CO2 lasers operating at 10.6 μm used in conjunction with optical feedback have the potential to selectively ablate residual dental composite and minimize inadvertent removal of enamel. Lasers Surg. Med. 27:103–110, 2000. © 2000 Wiley-Liss, Inc.

This article discusses two methods for improving the retrievability of cement-retained implant superstructures. One method involves incorporating a removal screw in the superstructure and the second method uses a small dimple on the abutment, accessed through a vent in the superstructure.

Prostheses can be attached to implants or implant abutments by screw retention, cementation, or with the use of set-screws. The indications for non-screw-retained restorations are discussed with respect to implant body position and surgical limitations for implant placement. The advantages and disadvantages of each method are outlined. A technique that uses a screw threaded into the implant restoration to displace the cemented restoration is presented. Use of this technique will allow predictable removal of the cemented restorations without damage to the prosthesis or abutment.

One hundred and sixty-five Cerinate porcelain veneers were placed by 11 private practice clinicians from diverse locations throughout the USA. The veneers were evaluated over a 3-year service period using Kodachrome photographs and grading of clinical characteristics by evaluators. The following factors were evaluated: (1) esthetics; (2) margin fit; (3) margin discoloration; (4) breakage; (5) gingival irritation; (6) patient acceptance; and (7) caries. Specific characteristics and their evaluations over three years were: (1) Esthetics started out excellent and remained that way; (2) Margin fit was acceptable at the beginning of the study and was actually perceived to improve, perhaps related to cement at the margins wearing and smoothing; (3) Margin discoloration started very low and became slightly worse; (4) Breakage was present during each of the 3 years, and 13 percent of veneers had some breakage after 3 years. Changes in clinical procedures are suggested in this paper to diminish this problem; (5) Gingival irritation was minimal throughout the study; (6) Patient acceptance was excellent at the beginning of the study and improved; and (7) Dental caries involvement was minimal, with only one veneered tooth showing caries involvement. Over the 3-year period, the veneers provided excellent service overall.