Biocompatibility of a restorative resin-modified glass ionomer cement applied in very deep cavities prepared in human teeth

This study evaluated whether a restorative resin-modified glass ionomer cement, Vitremer (VM), would be biocompatible with pulp tissue when used as a liner in very deep cavities prepared in young human permanent teeth. Two dental cements in current use as liner materials, Vitrebond (VB) and Dycal (DY), were compared to VM. Class V cavities were prepared in 36 sound premolars that were scheduled for extraction, and the cavity floor was lined with the restorative cement (VM) or a liner/base control cement (VB or DY). For VM specimens, the cavity floor was pretreated with a primer (polyacrylic acid plus 2-hydroxyethyl methacrylate). Teeth were extracted after 7 or 30 days and processed for microscopic evaluation. In the VM group, inward diffusion of dental material components through dentinal tubules, associated with disruption of the odontoblastic layer, moderate to intense inflammatory response, and resorption of inner dentin, was observed in 2 teeth at 7 days. These histologic features were observed in 1 tooth at 30 days. In the VB group, mild inflammatory reactions and tissue disorganization observed at 7 days were resolved at 30 days. No pulpal damage occurred in the DY specimens. Of the materials tested, only Vitremer was not considered biocompatible, because it caused persistent pulpal damage when applied in very deep cavities (remaining dentin thickness less than 0.3 mm).

Maintenance of pulpal vitality in a tooth with deep caries: a case report

Deep caries can induce severe inflammatory reactions. However, inflamed pulp can heal if the demineralization process is interrupted and inactivated sufficiently early. The aim of this case report is to describe the use of stepwise excavation to treat a mature permanent tooth that exhibited deep caries and apical periodontitis. A 12-year-old girl was experiencing lingering pain lasting for a few minutes in the mandibular left second molar when drinking cold water. Clinical and radiographic examinations suggested that a conservative therapeutic approach could be successful. The tooth was anesthetized and isolated, and the unsupported enamel was removed. The remaining affected dentin was left on the pulpal floor, which was protected by a thin layer of calcium hydroxide cement. The tooth was sealed with temporary cement. Three months later, pulpal sensitivity was reduced. The pulp was found to be healthy at a 9-month follow-up examination. The cavity was definitively restored with glass ionomer cement and composite resin applied with the sandwich technique. At the 4-year follow-up, the tooth remained functional, presenting standard color and satisfactory restoration. The periodontal tissues were healthy, and radiographic images indicated that the width of the periodontal ligament space was normal. This case demonstrates that clinical diagnosis should prevail over radiographic findings, even in cases where a radiographic widening of the periodontal ligament space suggests irreversible pulpal damage.

Effect of fiber posts on the fracture resistance of endodontically treated anterior teeth with cervical cavities: An in vitro study

STATEMENT OF PROBLEM

How the placement of fiber posts affects the fracture resistance of endodontically treated maxillary central incisors with cervical cavities is not well documented.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of fiber posts on the fracture resistance of endodontically treated maxillary central incisors with cervical cavities.

MATERIAL AND METHODS

Fifty extracted human maxillary central incisors were selected and divided into 5 test groups (n=10) according to the restoration strategy: GHT, control group; endodontically treated teeth (ETT) without endodontic posts; GCV, ETT with cervical cavities simulating coronal destruction; GCF, ETT with cervical cavities and carbon fiber posts; GGF, ETT with cervical cavities and glass fiber posts; and GCP, ETT with cervical cavities and composite resin posts. After the fiber posts had been cemented with a resin cement and the foundations had been placed, all specimens were quasi statically loaded at 45 degrees in a universal testing machine until fracture. All specimens were evaluated for fracture modes. The data were then analyzed by 1-way ANOVA, followed by multiple comparisons with the Tukey HSD test (α=.05). The mode of failure was determined by visual inspection.

RESULTS

The mean ±SD failure loads for the groups ranged from 718.2 ±89.8 N to 943.8 ±93.1 N. In a 1-way ANOVA followed by post hoc testing, GGFs had a higher fracture strength than all other groups (P≤.05). However, GCPs had a lower fracture strength than all other groups. Statistically significant differences were observed among groups (P≤.05), except between the GHT group and the GCF and GGF groups (P=.075, P=.226). All groups except GHT showed complete favorable fracture mode within the cervical third of the roots.

CONCLUSIONS

Within the limitations of this in vitro study, placement of glass fiber posts significantly improved the fracture resistance of endodontically treated maxillary central incisors with cervical cavities.

A new primary dental care service compared with standard care for child and family to reduce the re-occurrence of childhood dental caries (Dental RECUR): study protocol for a randomised controlled trial

BACKGROUND

In England and Scotland, dental extraction is the single highest cause of planned admission to the hospital for children under 11 years. Traditional dental services have had limited success in reducing this disease burden. Interventions based on motivational interviewing have been shown to impact positively dental health behaviours and could facilitate the prevention of re-occurrence of dental caries in this high-risk population. The objective of the study is to evaluate whether a new, dental nurse-led service, delivered using a brief negotiated interview based on motivational interviewing, is a more cost-effective service than treatment as usual, in reducing the re-occurrence of dental decay in young children with previous dental extractions.

METHODS/DESIGN

This 2-year, two-arm, multicentre, randomised controlled trial will include 224 child participants, initially aged 5 to 7 years, who are scheduled to have one or more primary teeth extracted for dental caries under general anaesthesia (GA), relative analgesia (RA: inhalation sedation) or local anaesthesia (LA). The trial will be conducted in University Dental Hospitals, Secondary Care Centres or other providers of dental extraction services across the United Kingdom. The intervention will include a brief negotiated interview (based on the principles of motivational interviewing) delivered between enrollment and 6 weeks post-extraction, followed by directed prevention in primary dental care. Participants will be followed up for 2 years. The main outcome measure will be the dental caries experienced by 2 years post-enrollment at the level of dentine involvement on any tooth in either dentition, which had been caries-free at the baseline assessment.

DISCUSSION

The participants are a hard-to-reach group in which secondary prevention is a challenge. Lack of engagement with dental care makes the children and their families scheduled for extraction particularly difficult to recruit to an RCT. Variations in service delivery between sites have also added to the challenges in implementing the Dental RECUR protocol during the recruitment phase.

TRIAL REGISTRATION

ISRCTN24958829 (date of registration: 27 September 2013), Current protocol version: 5.0.

Mandibular third molar surgery in 396 patients at a Norwegian university clinic: Morbidity recorded after 1 week utilizing an e-infrastructure for clinical research

OBJECTIVE

To evaluate morbidity 1 week after mandibular third molar (3M) surgery in the authors' department.

MATERIALS AND METHODS

A prospective 1-year clinical study of patients followed up for 1 week after 3M surgery was performed. Consecutive patients of 18 years or older having 3M surgery under local anaesthesia were included. Patients not able to attend a follow-up appointment after 1 week were excluded. Demographic data, indication for surgery and clinical findings were recorded. Outcome variables were days requiring analgesic, days absent from work/school and complications. All data recording was performed utilizing an e-infrastructure for clinical research (InReach, University Health Network, www.uhnsl.com).

RESULTS

Three hundred and ninety-six patients were examined 1 week after surgery. Mean number of days requiring analgesics was 3.8 and mean number of days absent from work/school after surgery was 0.6. Minor complications were reported by 7% of patients. Female patients reported more days requiring analgesics compared to male patients. Smokers had a higher odds ratio for being absent ≥ 3 days. Prophylactic removal of 3Ms was associated with fewer days requiring analgesics and days absent from work/school as compared to teeth with local disease.

CONCLUSION

Overall morbidity after 3M surgery was low. Compared to patients subjected to therapeutic removal of 3Ms, patients undergoing prophylactic removal seem to have less pain and a faster return to normal activities.

Alternative Use of an Oral Endotracheal Tube Fastener in a Patient with Junctional Epidermolysis Bullosa

This case report describes the alternative use of an oral endotracheal tube fastener in a pediatric patient with junctional epidermolysis bullosa. The patient underwent dental treatment in the operating room under general anesthesia and had a medical history of junctional epidermolysis bullosa, prior secondary anemia, clubbed feet, and past methicillin-resistant Staphylococcus aureus infection secondary to blistering. The oral endotracheal tube fastener was used in a nontraditional manner to avoid contact of the oral tube and tape with the epidermis and thus prevent blistering. Lubricated gauze was applied to the patient's eyes for protection, and lubricant was applied to the lips and perioral skin before intubation and during dental treatment. Postoperatively the patient exhibited minimal blistering secondary to intubation and dental treatment.

Conservative management of grossly carious mandibular first molar with a hemisection approach: a case report

The term hemisection refers to the removal or separation of a root-with its accompanying crown portion-from a 2-rooted tooth, such as a mandibular molar. A hemisection is considered a conservative treatment option for mandibular molars that would otherwise require extraction. A hemisection of an affected tooth helps to preserve the tooth structure and alveolar bone and is more economical than other treatment options. Therefore, hemisection may be a suitable alternative to extraction and implant therapy and should be discussed with patients during their consideration of treatment options. This case report describes a hemisection procedure in which the grossly carious distal half of an endodontically treated mandibular left first molar was removed.

Clinical outcomes of indirect composite restorations for grossly mutilated primary molars: a clinical observation

This study was conducted to report the clinical outcomes and the parental and child satisfaction of onlays for restoring mutilated primary molars. Twenty subjects, ages 3-8 years, with the presence of at least 1 mutilated primary molar (≥3 carious surfaces and a carious surface area ≥3/4 of the occlusal surface) were recruited. This study assessed the clinical success, gingival health, and parent/child satisfaction of 28 indirect composite onlays. The onlays showed a 100% retention rate at 12 months follow-up and a marginal integrity of 96.43%. High rates of satisfactory Alpha ratings for color stability (92.86%), surface texture (92.86%), and anatomic form (100%), coupled with significant improvements in gingival health of the restored teeth (P < 0.05), were reported. Indirect composite onlays successfully restored anatomic form and function of the grossly decayed primary molars--with shorter chairside times--while satisfying the esthetic demands of the young pediatric patients.

Low-shrinkage composites: an in vitro evaluation of sealing ability after occlusal loading

The objective of this in vitro study was to compare the microleakage of a flowable low-shrinkage-stress resin composite--in a Class II fatigue-loading design when used as a 4 mm dentin replacement--to a conventionally layered silorane-based resin composite. Eighty standardized 4 mm deep cavities, divided into 4 subgroups, were restored with the 2 tested materials. Half of the restorations were submitted to mechanical loading, and all of the restorations were prepared for microleakage evaluation. The evaluation of the marginal adaptation to dentin was performed with scanning electron microscopy. The results showed that both silorane-based composite groups had higher rates of microleakage in comparison to the low-shrinkage-stress resin composite groups.

Selective removal of carious human dentin using a nanosecond pulsed laser operating at a wavelength of 5.85 μm

Less invasive methods for treating dental caries are strongly desired. However, conventional dental lasers do not always selectively remove caries or ensure good bonding to the composite resin. According to our previous study, demineralized dentin might be removed by a nanosecond pulsed laser operating at wavelengths of around 5.8 μm . The present study investigated the irradiation effect of the light on carious human dentin classified into "remove," "not remove," and "unclear" categories. Under 5.85-μm laser pulses, at average power densities of 30 W/cm² and irradiation time of 2 s, the ablation depth of "remove" and "not remove," and also the ablation depth of "unclear" and "not remove," were significantly different (p<0.01 ). The ablation depth was correlated with both Vickers hardness and Ca content. Thus, a nanosecond pulsed laser operating at 5.85  μm proved an effective less-invasive caries treatment.

Matrixing for MID success

The proper use of matrices can lead to successful, stable dental restorations. Their importance is further advanced in MID restorations. The 3 Cs of contour, contact, and control properly exercised with correct placement of matrices can enhance the long-term success of any restoration. Matrices create healthy gingival contours, mimic natural tooth contours, and also create good healthy contacts. All of these benefits can be achieved while controlling the flow of bonding products from the gums and keeping sulcular fluids from contaminating the bonding surfaces.

Effectiveness of Different Mechanical Methods on Dentin Caries Removal: Micro-CT and Digital Image Evaluation

PURPOSE

To determine the caries removal effectiveness (CRE) and minimal invasive potential (MIP) of caries excavation methods using digital imaging and microtomography analyses.

METHODS

Twelve human molars with occlusal caries lesions in dentin were randomly divided into three groups (carbide bur, exacavator, and polymer bur). They were sectioned mesiodistally, and standardized digital and computed microtomography x-ray (micro-CT) images were taken from each section before and after caries excavation. On each image, initial carious dentin (IC), prepared cavity (PC), and residual caries (RC) were defined according to visual criteria using ImageJ software. CRE was determined based on the RC/IC ratio, whereas MIP was determined by the PC/IC ratio. Data were analyzed using one-way analysis of variance and Student t-test or with Kruskal-Wallis and Student-Newman-Keuls test. The level of significance was set at 0.05.

RESULTS

For both digital image and micro-CT analysis, the carbide bur showed higher CRE values than the excavator (p=0.0063 and p=0.0263, respectively) and the polymer bur (p=0.0028 and p=0.0005, respectively). The latter two presented similar results (p>0.05). Regarding MIP, for the digital image analysis, the polymer bur was different from the carbide bur (p=0.0030) but was not different from that of the excavator (p=0.1240). For micro-CT analysis, the MIP values of all the groups were significantly different, and the polymer bur was the most conservative method (p<0.05).

CONCLUSIONS

The carbide bur was the most effective method for caries removal but was not completely conservative. The polymer bur and excavator presented low invasive potential but were not able to remove all of the carious dentin.

Bonding of Adhesive Luting Agents to Caries-affected Dentin Induced by a Microcosm Biofilm Model

OBJECTIVES

To evaluate the bond strength of adhesive luting agents applied to caries-affected dentin (CAD).

METHODS

Thirty-six noncarious human third molars were abraded to expose an occlusal dentin surface. Caries lesions were induced in half of the samples using a microcosm biofilm model. Biofilm was cultivated under an anaerobic atmosphere for 14 days in a medium enriched with mucin. The same medium containing 1% sucrose was alternated for 4 hours per day. Cylinders of resin cement (RelyX ARC, RelyX U200, or BisCem) were built up over the dentin substrate and submitted to shear bond load. The samples were then longitudinally sectioned. The hardness and elastic modulus of dentin were measured at different depths from the occlusal surface. A three-dimensional finite element simulation was performed to analyze the residual stress distribution during the shear bond strength test. Bond strength data were analyzed by two-way analysis of variance (ANOVA) and hardness and elastic modulus by split-plot ANOVA. Multiple comparisons were performed with the SNK test (α=0.05).

RESULTS

For all cements, the highest bond strengths were observed in sound dentin. Relyx ARC bond strength was similar to that of RelyX U200 for both substrates; BisCem had the lowest values. CAD had lower hardness (above a depth of 100 μm) and elastic modulus (above a depth of 150 μm) values than sound dentin. Stress distribution during the bond strength test was similar under all experimental conditions.

CONCLUSION

Impairment of the mechanical properties of dentin promoted by carious lesions reduced the bond strength of adhesive luting agents.

The Effect of Combining Radiographs and DIAGNOdent With Visual Examination on Detection and Treatment Decisions of Noncavitated Occluso-dentinal Caries

The aim of this laboratory study was to evaluate the effectiveness of incorporating radiographic examination and DIAGNOdent with visual examination for the detection and treatment of noncavitated occluso-dentinal caries. Four examiners examined the occlusal surfaces of 160 extracted posterior teeth. Teeth were examined three times with a one-month interval in between. The first examination was visual (V), the second examination was visual with radiograph (VR), and the third examination was visual with radiograph and DIAGNOdent (VRD). Examiners were asked to detect the presence of caries (if any) and identify the extent of caries (if present; ie, enamel or dentin). The examiners were also asked to choose a treatment for each tooth. The examined teeth were later sectioned, and the presence of caries was charted as 0 = no caries, 1 = caries confined to enamel, 2 = caries in the outer dentin, and 3 = caries in the inner dentin. Sensitivity, specificity, area under the curve (Az values), rank correlation coefficient, interexaminer reproducibility, and McNemar χ(2) tests were calculated. VR had statistically higher specificity and lower sensitivity than V and VRD. The means of Az values ranged from 0.58 to 0.63, with no statistical difference between the three examinations (p>0.05). The means of the rank correlation coefficients with histology for detection of dentinal caries were 0.48, 0.23, and 0.44 using V, VR, and VRD, respectively. Interexaminer reproducibility was best for V alone. The percentages of teeth indicated for restorative treatment were 31%, 33%, and 41% using V, VR, and VRD, respectively. The percentages of teeth correctly treated according to histology were 69.4%, 70.0%, and 67.5% using V, VR, and VRD, respectively. There was no difference in the accuracy of treatment decisions between the three examination points (p>0.05). The addition of radiographs and DIAGNOdent to visual examination did not have a significant effect on the improvement of the detection or treatment decisions of examiners of noncavitated occluso-dentinal carious lesions.

Isolation of dentin tissue by usinga new liner biodentine at management of simulated experimental caries

The aim of our study was the use of different types of isolation systems in the treatment of experimentally simulated dental caries that will allow to present additional comparative characteristic for morphological responses of the pulp.For realization of this purpose, 3 systems have been selected: UltraBlend (Ultradent), Biodentine (Septodont) and adhesive system Prime&Bond NT (Dentsply). The study was conducted at the laboratory of Alexander Natishvili Institute of Morphology. For this experiment, 12 male, 6 months of age rabbits were selected. There were created 3 experimental groups, each of which included 4 rabbits. Restoration of the teeth in experimental rabbits with Biodentine revealed sufficient physical properties enabling the operator most comfortably conduct his/her clinical activities: kneading, bringing into caries cavity, condensing and filling dental defect. Isolation of dentin by Biodentine doesn't contradict and/or reduce application of adhesive systems, which is also important for teeth restorations. Biodentine has optimal working time (final curing 10-12 minutes) enabling the operator to conduct maximal formation of material at the bottom of caries cavity.

Microtensile bond strength of etch-and-rinse and self-etch adhesives to artificially created carious dentin

This article evaluates a pH-cycling model for simulation of caries-affected and caries-infected dentin (CAD and CID, respectively) surfaces, by comparing the bond strength of an etch-and-rinse and a self-etch adhesive system. For both adhesives, bonding to sound dentin (SD) showed that the microtensile bond strength (μTBS) values of SD, CAD, and CID were SD > CAD > CID (P < 0.05). Knoop microhardness number mean values followed the same trend. Adhesive systems were not able to totally penetrate into CAD and CID, forming more irregular resin-dentin interdiffusion zones and atypical resin tags than SD. The tested in vitro pH-cycling caries model allowed the evaluation of specific dentin substrate alterations in response to μTBS. The type of dentin and its histological structure played an important role in etch-and-rinse and self-etch bonding, as lower μTBS values were attained in CAD and CID.