Clinical performance of a light-cured denture base material compared to polymethylmethacrylate—a randomized clinical study

The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use.     

Does a mandibular RDP and new maxillary CD improve masticatory efficiency and quality of life in patients with a mandibular Kennedy class I arch?

Objectives

To evaluate the change in masticatory efficiency and quality of life of patients treated with mandibular Kennedy class I removable partial dentures (RPDs) and maxillary complete dentures at the Department of Dentistry of the Federal University of Rio Grande do Norte.

Materials and methods

A total of 33 Kennedy class I patients were rehabilitated with maxillary complete dentures, and mandibular RPDs were selected for this non-randomized prospective intervention study. The patients had a mean age of 59.1 years. Masticatory efficiency was evaluated by colorimetric assay using fuchsin capsules. The measurements were conducted at baseline and 2 and 6 months after prosthesis insertion. Quality of life was evaluated using the Oral Health Impact Profile (OHIP-14) at baseline and 6 months after denture insertion. The Kolmogorov-Smirnov normality test was applied. Masticatory efficiency was evaluated by repeated measures ANOVA. Oral health-related quality of life was compared using the paired t test.

Results

There was no statistically significant difference in masticatory efficiency after denture insertion (p?=?0.101). Significant differences were found (p?=?0.010) for oral health-related quality of life. A significant improvement in psychological discomfort (p?<?0.01) and psychological disability (p?<?0.01) was observed. Mean difference value (95 % confidence interval) was 6.8 (3.8 to 9.7) points, reflecting a low impact of oral health on quality of life, considering the 0–56 range of variation of the OHIP-14 and a Cohen’s d of 1.13.

Conclusion

According to the results of the present study, rehabilitation with Kennedy class I RPDs and complete dentures did not influence masticatory efficiency but improved oral health-related quality of life.

Clinical relevance

The association between the patient’s quality of life and the masticatory efficiency is important for treatment predictability.

     

In vitro comparison of implant- versus gingiva-supported removable dentures in anterior and posterior applications

Objectives

Removable dentures with different denture teeth may provide different performance and resistance in implant and gingival situations, or anterior and posterior applications.

Materials and methods

Two situations of removable dentures were investigated: gingiva (flexible) and implant (rigid) bearing. For simulating the gingiva/jaw situation, the dentures were supported with flexible lining material. For the implant situation, implants (d?=?4.1 mm) were screwed into polymethylenmethacrylate (PMMA) resin. Two commercial (Vita-Physiodens MRP, SR Vivodent/Orthotyp DCL) and two experimental materials (EXP1, EXP2) were investigated in anterior (A) and posterior (P) tooth locations. Chewing simulation was performed, and failures were analyzed (microscopy, SEM). Fracture strength of surviving dentures was determined.

Results

Only EXP1 revealed failures during chewing simulation. Failures varied between anterior and posterior locations, and between implant (P:4x; A:7x) or gingiva (P:1x; A:2x) situations. Kaplan-Meier log-rank test revealed significant differences for implant situations (p?<?0.002), but not for gingiva bearing (p?>?0.093). Fracture testing in the implant situation provided significantly highest values for EXP2 (1476.4?±?532.2 N) in posterior location, and for DCL (1575.4?±?264.4 N) and EXP2 (1797.0?±?604.2 N) in anterior location. For gingival bearing, significantly highest values were found for DCL/P (2148.3?±?836.3 N), and significantly lowest results for EXP1/A (308.2?±?115.6 N). For EXP1?+?EXP2?+?Vita/P and for EXP1/A no significant differences were found between implant- or gingiva-supported situations.

Conclusions

Anterior and posterior teeth showed different material-dependent in vitro performance, further influenced by implant/gingiva bearing. While an implant in anterior application increased fracture strength of two materials, it decreased fracture values of 3/4 of the materials in posterior application.

Clinical relevance

Survival of denture teeth may be influenced by material, oral position, and bearing situation.

     

Radiologic bone loss in patients with bisphosphonate-associated osteonecrosis of the jaws: a case–control study

Objectives

Most patients with bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) report a previous tooth extraction at the necrosis site before the diagnosis was made. At older ages, most teeth are extracted due to periodontal disease, which is per se another BP-ONJ trigger factor. The aim of this study was to evaluate the periodontal status of BP-ONJ patients using panoramic radiographs compared to a control.

Materials and methods

All patients treated for BP-ONJ up to January 1, 2010 comprised the study. The very first panoramic radiograph was analyzed. The number of remaining teeth and the radiographic bone loss from the cemento-enamel junction to the crestal bone were measured. For each patient, one control was analyzed (matching for gender and age).

Results

One hundred twenty-nine BP-ONJ panoramic radiographs and 129 controls were analyzed (68 women, 61 men; 67.3?±?9.7 years; osteoporosis [n?=?11], breast cancer [n?=?33], multiple myeloma [n?=?61], prostate cancer [n?=?24]). The average number of remaining teeth was 12.9?±?8.4 for BP-ONJ and 16.4?±?9.4 for the control (p?=?0.02). The average radiographic bone loss was 5.5?±?2.3 mm for BP-ONJ and 3.1?±?1.1 mm for the control (p?<?0.001); 96.6 % of BP-ONJ and 77.5 % had radiographic bone loss of more than 5 mm. Radiographic bone loss in the molar region was the highest for both groups (BP-ONJ 6.0?±?2.3 mm; control 3.6?±?1.4 mm).

Conclusion

Prevalence and severity of periodontal disease in patients with BP-ONJ is higher compared to healthy controls.

Clinical relevance

Patients with periodontal disease might be at a higher risk of developing BP-ONJ; therefore, periodontal disease therapy in patients who are about to receive bisphosphonates should be undertaken.     

Does dental and oral health influence the development and course of bisphosphonate-related osteonecrosis of the jaws (BRONJ)?

Purpose

The main causes for the occurrence of bisphosphonate-related osteonecrosis of the jaws (BRONJ) are the application of aminobisphosphonates and the extraction of teeth. However, the question which factors in dental and oral health are relevant has not been answered completely.

Materials and methods

In a retrospective study, 50 patients who were treated with BRONJ between 2000 and 2009 were analyzed. As underlying diseases, they suffered from breast cancer (n?=?24), multiple myeloma (n?=?16), prostate cancer (n?=?5), osteoporosis (n?=?4), and kidney cancer (n?=?1). The data were collected from the patient charts of the treating dentists, oral and maxillofacial surgeons, general practitioners, and oncologists. The time of occurrence of BRONJ after treatment onset with bisphosphonates (BP) was examined with Kaplan–Meier estimator and logrank test (level of significance 0.05).

Results

At the time of BP treatment, onset the decayed, missing, and filled teeth (DMFT) index was 20.5?±?4.2. Patients with a DMFT value less than 20 showed a significantly longer BRONJ-free time interval after BP treatment onset with 39.7?±?1.1 months compared to patients with a DMFT value higher than 20, in whom BRONJ appeared after 14.4?±?2.8 months (p?<?0.001). However, the DMFT value had no influence on the success rate of BRONJ treatment. As a pre-existing oral disease, 60 % of the patients (n?=?30) had marginal periodontitis; 38 % (n?=?19), apical periodontitis; and 22 % (n?=?11), a pressure lesion from their dentures. In patients with marginal periodontitis, BRONJ occurred after 26.3 months (range 20.9–31.3) and in patients without marginal periodontitis, after 27.4 months (range 14.6–40.1) (p?=?0.58). Only 20 % of the patients with marginal periodontitis received adequate treatment. Without parodontal treatment, BRONJ occurred 15 months earlier compared to patients with parodontal treatment (p?=?0.12). The state of the periodontium did not influence the healing rate of BRONJ (p?>?0.999).

Conclusion

The present study highlights the great benefit of good dental and oral health in the prevention of BRONJ; but it also shows that after the appearance of BRONJ, these factors do no longer seem to play a relevant role in the disease course.     

Oral squamous cell carcinoma in the vicinity of dental implants

Objectives

The study at hand presents a cohort of patients treated for carcinomas in the vicinity of dental implants for identification of potential risk factors.

Materials and methods

The retrospective analysis covers patients treated for peri-implant carcinoma at our department between 1995 and 2011. An additional literature search focused likewise on peri-implant carcinomas. Obtained articles were screened for relevant risk factors and discussed in relation to our patient cohort.

Results

Fifteen patients were treated for peri-implant carcinoma. Six reported ongoing alcohol/tobacco consumption. Nine had a previously reported carcinoma of whom six had received radiotherapy after surgery. Time from implant placement until carcinoma diagnosis was 53.4 months on average. The literature search revealed 25 patients with peri-implant carcinoma and one with a sarcoma. Eight patients reported alcohol/tobacco consumption. Most patients exhibited risk factors for possible malignant transformation: previous carcinoma (n?=?12), lichen (n?=?4), irradiation (n?=?3), and leukoplakia (n?=?3). The average time until diagnosis was 51.6 months.

Conclusions

Smoking, alcohol consumption, and the history of previous carcinoma characterize patients at risk for a peri-implant carcinoma. A balanced gender ratio might point at a higher risk for woman and additional risk factors promoting carcinogenesis apart from tobacco and alcohol consumption, a novel finding that has to be proven by larger patient counts.

Clinical relevance

The incidence of carcinomas next to dental implants is low but may attain clinical relevance with raising implant figures worldwide. Patients at risk potentially profit from individualized recall intervals and careful evaluation.     

Are implants more reliable than severely compromised endodontically treated teeth as abutments for zirconia-based FPDs?

Objectives

The aim was to study the impact of the defect size of endodontically treated incisors compared to dental implants as abutments on the survival of zirconia two-unit anterior cantilever-fixed partial dentures (2U-FPDs) during 10-year simulation.

Materials and methods

Human maxillary central incisors were endodontically treated and divided into three groups (n?=?24): I, access cavities rebuilt with composite core; II, teeth decoronated and restored with composite; and III as II supported by fiber posts. In group IV, implants with individual zirconia abutments were used. Specimens were restored with zirconia 2U-FPDs and exposed to two sequences of thermal cycling and mechanical loading. Statistics: Kaplan–Meier; log-rank tests.

Results

During TCML in group I two tooth fractures and two debondings with chipping were found. Solely chippings occurred in groups II (2×), IV (2×), and III (1×). No significant different survival was found for the different abutments (p?=?0.085) or FPDs (p?=?0.526). Load capability differed significantly between groups I (176 N) and III (670 N), and III and IV (324 N) (p?<?0.024).

Conclusion

Within the limitations of an in vitro study, it can be concluded that zirconia-framework 2U-FPDs on decoronated teeth with/without post showed comparable in vitro reliability as restorations on implants. The results indicated that restorations on teeth with only access cavity perform worse in survival and linear loading.

Clinical relevance

Even severe defects do not justify per se a replacement of this particular tooth by a dental implant from load capability point of view.     

Two-year results of vital pulp therapy in permanent molars with irreversible pulpitis: an ongoing multicenter randomized clinical trial

Objectives

Oral healthcare expenses are increasing rapidly as a result of the growth of high-cost health technologies worldwide. In many developing/developed countries, low-cost tooth extraction is the alternative treatment option for a high-cost root canal therapy (RCT) for management of human molars with irreversible pulpitis. Vital pulp therapy with calcium-enriched mixture cement (VPT/CEM) as a new alternative treatment option has demonstrated excellent treatment outcomes up to 1 year; if 2-year radiographic/clinical effectiveness as well as cost-effectiveness of the VPT/CEM is also non-inferior compared with RCT, it can serve as a viable treatment for mature molars with irreversible pulpitis.

Materials and methods

In this prospective, multicenter (n?=?23), non-inferiority clinical trial, 407 patients were randomized to either one-visit RCT (n?=?202) or VPT/CEM (n?=?205) for 27 months. In this part of study, the primary outcome measure was the 2-year clinical and radiographic treatment outcomes. Cost-effectiveness was also analyzed.

Results

Mean follow-up times were 24.62?±?0.72 and 24.61?±?0.69 months in RCT (n?=?166) and VPT/CEM (n?=?166) arms, respectively. Clinical success rates in the two study arms were equal (98.19 %); however, radiographic success rates were 79.5 and 86.7 % in RCT and VPT/CEM arms, respectively, with no statistical difference (P?=?0.053). The treatment time span mean was approximately three times greater in the RCT than in the VPT/CEM arm (94.07 vs. 31.09 min; P?<?0.001). RCT had a cost of 171.5K per molar tooth compared with 44.5K for VPT.

Conclusions

VPT/CEM reduced time and cost spent. When considering clinical as well as cost-effectiveness of VPT/CEM, this treatment option is not only non-inferior but also superior to RCT in mature permanent molar teeth with established irreversible pulpitis.

Clinical relevance

Vital pulp therapy with CEM is a cost-effective and reliable biological technique for endodontic treatment of permanent molar teeth with irreversible pulpitis and can be recommended for general clinical practice.     

Vasodilator isoxsuprine alleviates symptoms of oral submucous fibrosis

Objectives

The aim of the study was to compare the effectiveness of vasodilator isoxsuprine to dexamethasone with hyaluronidase injections and physiotherapy in the treatment of oral submucous fibrosis.

Materials and methods

Forty patients with oral submucous fibrosis were randomly assigned into three groups. Group A patients (n?=?15) received 10 mg isoxsuprine tablets four times per day, group B (n?=?15) biweekly dexamethasone with hyaluronidase intralesional injections, and group C (n?=?10) placebo tablets. In addition, all patients were instructed physiotherapy exercises. The treatment time was 6 weeks and patients were followed-up for 4 months thereafter. The effect of the treatment was evaluated by measurements of inter-incisal distance and oral burning sensation and evaluation of histological findings of the diseased mucosa.

Results

Mouth opening increased and burning sensation decreased significantly in all groups, but the effects were significantly greater in groups receiving either oral isoxsuprine or dexamethasone with hyaluronidase injections in addition to physiotherapy. The decrease in burning sensation occurred more rapidly in patients receiving intralesional dexamethasone with hyaluronidase. Histological improvement was not observed in any of the groups.

Conclusions

Oral isoxsuprine as well as dexamethasone with hyaluronidase injections combined to physiotherapy alleviate symptoms of oral submucous fibrosis significantly more efficiently than physiotherapy alone.

Clinical relevance

Oral isoxsuprine can be considered as a new candidate drug for the treatment of oral submucous fibrosis. Physiotherapy exercises provide relief of symptoms and should be instructed to all patients.     

Volume reduction of cystic lesions after surgical decompression: a computerised three-dimensional computed tomographic evaluation

Objectives

This study was performed to evaluate the three-dimensional radiographic variation in mandibular odontogenic cystic lesions after decompression.

Materials and methods

Pre- and post-decompression computed tomography (CT) evaluations in 20 patients affected by keratocysts (n?=?10), dentigerous cysts (n?=?9) and ameloblastoma (n?=?1) were analysed using software designed for three-dimensional measurement of volumes; the results were correlated with treatment duration, age, sex and histological type.

Results

The mean (range) decompression time was 5.70 (3–12)?months. The mean (SD) pre- and post-decompression volumes were 9.50 (7.74) and 4.65 (4.34)?cm³, respectively (P?<?0.001), with a mean (SD) reduction of 49.86 % (19.34 %). The volume reduction was positively correlated with the duration of decompression (P?<?0.001), whereas no correlations with other variables were found (P?=?0.2357). The median monthly reduction in cyst volume was 11.34 % (mean, 13.52 %; range, 4.45–30.43 %) (P?<?0.001).

Conclusions

This three-dimensional CT investigation demonstrated the effectiveness of decompression in the treatment of mandibular odontogenic cystic lesions and showed a positive correlation between the duration of treatment and volume reduction.

Clinical relevance

Decompression treatment, which is simple to perform and generally well-accepted by patients, is a reliable method to considerably reduce the volume of mandibular odontogenic cystic lesions before surgical removal. Extended decompression time seems to improve results of the reduction process.     

Nanohybrid vs. fine hybrid composite in extended class II cavities: 8-year results

Objective

In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended class II cavities was observed over 8 years.

Materials and methods

Thirty patients received 68 direct resin composite restorations (Solobond M/Grandio, Voco—n?=?36; Syntac/Tetric Ceram, Ivoclar Vivadent—n?=?32) by one dentist in a private practice. Thirty-five percent of cavities revealed no enamel at the bottom of the proximal box, 48 % of cavities provided <0.5 mm remaining proximal enamel width. Restorations were examined according to modified US Public Health Service criteria at baseline, after 6 months, and 1, 2, 4, 6, and 8 years.

Results

All patients attended the 8-year recall. The overall success rate of all restorations was 98.5 % (Kaplan–Meier survival algorithm). One Grandio restoration was lost due to bulk fracture. One Tetric Ceram restoration suffered drop out due to cusp fracture having been not related to the restoration itself. Neither restorative materials nor localization of the restorations had a significant influence on any criterion except color (darker for Grandio). Restorations in molars performed inferior compared with premolars regarding marginal integrity (4 years), restoration integrity (6, 12, 24, 48, and 96 months), and tooth integrity (12, 48, 72, and 96 months). Irrespective of the resin composite used, significant changes over time were found for all criteria evaluated in clinical examinations. Beyond the 4-year recall, marginal staining increased. Both phenomena were found earlier in molars compared with premolars. Tooth integrity significantly deteriorated because of increasing enamel cracks and chippings over time.

Conclusions

Both materials performed satisfactorily over the 8-year observation period. Due to the extension of the restorations, wear was clearly visible after 8 years of clinical service.

Clinical relevance

Hybrid and nanohybrid resin composites show an acceptable clinical performance after 8 years of service.     

Do chlorhexidine and ethanol improve bond strength and durability of adhesion of fiber posts inside the root canal?

Objectives

The aim was to investigate the effects of chlorhexidine and ethanol pretreatment of the root canal on push-out bond strengths and durability of adhesion of fiber posts luted with two different adhesive strategies.

Materials and methods

One hundred twenty human anterior teeth were endodontically treated. After post space preparation, the root canals were irrigated using 1 % sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation followed by distilled water (control). In pretreatment (PT) group, chlorhexidine (CHX) root canals were irrigated using 2 % chlorhexidine; and in the PT group, 99 % ethanol was used prior application of the luting agent. Two different post-and-luting systems with an etch-and-rinse (CX) adhesive approach (n?=?60) and a self-adhesive resin cement (RX; n?=?60) were inserted into the root canals. Bond strengths were evaluated initially and after thermocycling and storage for 6 months using push-out tests.

Results

Bond strength was significantly affected by the adhesive strategy (p?<?0.0005), the pretreatment (p?<?0.0005) and the location inside the root canal (p?<?0.0005; repeated measurement ANOVA). Ethanol significantly increased bond strengths irrespective of the luting agent used compared to the control and CHX group (p?<?0.05; Tukey's B).

Conclusion

Ethanol significantly increased bond strength of the CX and the RX system inside the root canal and could be recommended as a final rinse for luting fiber posts using an ethanol-based etch-and-rinse adhesive system or self-adhesive resin cement.

Clinical relevance

PT of the root canal using ethanol seems to facilitate adhesive luting of fiber posts with the tested adhesive system and luting cements.     

Autogenous auricular cartilage graft in temporomandibular joint ankylosis—an evaluation

Purpose

Recurrence is a major problem after release of temporomandibular joint (TMJ) ankylosis. The purpose of this study was to evaluate the use of autogenous auricular cartilage graft as an interposition material after arthroplasty for TMJ ankylosis.

Materials and methods

Ten patients (M?=?4; F?=?6) with TMJ ankylosis were treated with autogenous auricular cartilage graft interposition arthroplasty. Minimal follow-up was 2 years. The possible reasons for ankylosis and pre- and postoperative mouth opening at final follow-up were recorded.

Results

There was a single case of bilateral ankylosis, and a total of 11 joints were operated. The cause of ankylosis could be traced to trauma (n?=?7) and ear infection (n?=?3). The ages at operation ranged from 6 to 23 years. Postoperative mouth opening was satisfactory in all patients except one in whom relapse occurred. No donor site deformity was observed in any of the patients.

Conclusion

Autogenous auricular cartilage graft is a good interposition material for successful treatment of TMJ ankylosis.     

Postoperative tooth sensitivity with a new self-adhesive resin cement—a randomized clinical trial

Objectives

This study evaluated and compared sensitivity of teeth after cementation of full-coverage crowns with a new self-adhesive resin cement (SARC). A resin-modified glass ionomer cement (RMGIC) served as control.

Materials and methods

Eighty-eight full-coverage crowns were cemented to vital teeth with either the self-adhesive cement iCem (Heraeus Kulzer; n?=?44) or the RMGIC GC Fuji PLUS (GC, n?=?44). Before preparations, patients were questioned for sensitivity (patient sensitivity, PS). In addition, air was blown for 2 s onto the buccal cementoenamel junction (air sensitivity, AS), and ice spray was applied in the cementoenamel junction area (ice sensitivity, IS). Patient responses were recorded with a visual analog scale. After cementation of the crowns, patients were recalled for follow-up (f/u) visits at 1 day, 1 week, and 3 weeks. PS, AS, and IS were recorded during each visit. Data were analyzed with Mann–Whitney U tests.

Results

The two groups revealed comparable sensitivity scores at baseline. SARC showed significantly lower PS sensitivity scores at 1 day (p?=?0.02) and significantly lower AS scores at 1-week follow-up (p?=?0.01). IS generally produced the highest sensitivity scores with SARC revealing significantly lower scores at all follow-up visits.

Conclusion

Cementation of crowns with the SARC tested in this study resulted in overall lower postoperative sensitivity than with the RMGIC.

Clinical relevance

Among other clinical advantages, some self-adhesive resin cements seem to lower postoperative sensitivity of crowned teeth.     

Clinical longevity of ceramic laminate veneers bonded to teeth with and without existing composite restorations up to 40 months

Objectives

This study evaluated the survival rate of ceramic laminate veneers bonded to teeth with and without existing composite restorations (ECR).

Materials and methods

Twenty patients (mean age: 49.7 years) received 92 feldspathic ceramic laminate veneers (Shofu Vintage AL) on the maxillary teeth (intact teeth: n?=?26; teeth with ECR: n?=?66). Preparations with incisal overlap were made, and ECR of good quality were not removed but conditioned using silica coating (CoJet) and silanization (ESPE-Sil). Enamel and dentin were etched with 38 % H₃PO₄ for 15–30 s and rinsed 30 s; adhesive resin (Excite) was applied, and laminate veneers were then cemented (Variolink Veneer). Restorations were evaluated at baseline and thereafter every 6 months using modified United States Public Health Service criteria.

Results

Mean observation period was 21.6 months. Overall, five absolute failures were encountered (fractures: n?=?3; chipping: n?=?1; debonding: n?=?1), resulting in a survival rate of 94.6 % (Kaplan–Meier). Survival rates of the laminates bonded to teeth without (96 %) and with ECR (93.5 %) did not show significant differences (p?>?0.05). Slight marginal defects (16 of 87 laminates) and slight marginal discoloration at the margins were noted (12 of 87 laminates) until the final recall. Secondary caries and endodontic complications were not detected in any of the teeth.

Conclusion

The clinical survival of ceramic laminate veneers up to 40 months was not significantly influenced when they were bonded onto intact teeth or onto teeth with ECR.

Clinical relevance

When no caries is present, it may not be necessary to replace existing composite restorations prior to cementation of ceramic laminate veneers.     

In vitro comparison of mechanical properties and degree of cure of bulk fill composites

Objectives

The aim of our study was to measure and compare degree of conversion (DC) as well as micro- (indentation modulus, E; Vickers hardness, HV) and macromechanical properties (flexural strength, σ; flexural modulus, E _flexural) of two recently launched bulk fill resin-based composites (RBCs): Surefil® SDR? flow (SF) and Venus® bulk fill (VB).

Materials and methods

DC (n?=?6) was investigated by Fourier transform infrared spectroscopy (FTIR) in clinical relevant filling depths (0.1, 2, and 4 mm; 6 mm bulk, 6 mm incremental) and irradiation times (10, 20, 40 s). Micro- (n?=?6) and macromechanical (n?=?20) properties were measured by an automatic microhardness indenter and a three-point bending test device after storing the specimens in distilled water for 24 h at 37°C. Furthermore, on the 6-mm bulk samples, the depth of cure was determined. A field emission scanning electron microscope was used to assess filler size. Results were evaluated using one-way analysis of variance, Tukey’s honest significance test post hoc test, a multivariate analysis (α?=?0.05) and an independent t test. Weibull analysis was used to assess σ.

Results

VB showed, in all depth, significant higher DC (VB, 62.4–67.4 %; SF, 57.1–61.9 %), but significant lower macro- (VB, E _flexural?=?3.6 GPa; σ?=?122.7 MPa; SF, E _flexural?=?5.0 GPa; σ?=?131.8 MPa) and micromechanical properties (VB, E?=?7.3–8.8 GPa, HV?=?40.7–46.5 N/mm²; SF, E?=?10.6–12.2 GPa, HV?=?55.1–61.1 N/mm²). Both RBCs showed high reliability (VB, m?=?21.6; SF, m?=?26.7) and a depth of cure of at least 6 mm at all polymerization times. The factor “RBC” showed the strongest influence on the measured properties (η ²?=?0.35–0.80) followed by “measuring depth” (η ²?=?0.10–0.46) and “polymerization time” (η ²?=?0.03–0.12).

Conclusions

Significant differences between both RBCs were found for DC, E, σ, and E _flexural at all irradiation times and measuring depths.

Clinical relevance

Curing the RBCs in 4-mm bulks for 20 s can be recommended.     

External pin fixation for stabilization of the mandible—comeback of a method: historical review and first experiences with the ‘mandible external fixator’

Background

The market-release of a modified ‘mandible external fixator’ appliance prompted us to reconsider the issues of pin fixation.

Materials and methods

The first product line of the ‘mandible external fixator set—Phase1’ (Synthes Maxillofacial®, Paoli, USA) contains the three classical basic components: percutaneous pins, clamps, and pre-bent connecting rods. The innovative features are a lightweight titanium construct and the snap-on design of the clamps. The framework is assembled by a single connecting bar (monofixator) in the so-called visor-style technique.

Indications

The indication was restricted to: (1) pathological fractures, e.g., in infected osteoradionecrosis; (2) resectional defects; and (3) emergency care of mandible fractures in a multi-piece, heavy comminution, or defect pattern.

Patients

The mandible external fixator was used in a series of ten patients (all male, 39–73 years), for head and neck tumor sequelae in eight cases (n?=?5—curatively, n?=?3—palliation) and in two polytrauma cases.

Results

All patients had benefited from the functional restitution of the mandibular continuity avoiding major surgical exposure and additional soft tissue damage. The application using a ‘visor-style technique’ was appropriate for bridging defects or single comminution zones (n?=?9). In the emergency care of a polytraumatized patient with multifragmentation all over the mandible divisions, it did not contribute to an adequate realignment. In curative tumor treatment (patients n?=?5), a conversion either to internal fixation (n?=?2) or revascularized bone grafting (n?=?3) ensued after prolonged intervals of 40–170 days. Pin track infections or loosening did not occur.

Conclusion

The hallmark of external pin fixation is its atraumatic soft tissue management. Hence, it offers peculiar options in singular comminution or defect areas associated with bone pathology and/or soft tissue alterations.     

Effectiveness of a combination denture-cleaning method versus a mechanical method: comparison of denture cleanliness,patient satisfaction,and oral health-related quality of life

Purpose

Effective denture plaque control is necessary in elderly individuals to prevent oral and systemic diseases. However, comparative studies of denture cleaning methods are limited, especially those investigating patient satisfaction. The present study aimed to evaluate effectiveness of a mechanical denture cleaning method versus a combination of mechanical and chemical methods in terms of denture cleanliness, patient satisfaction, and oral health-related quality of life (OHRQoL).

A randomized clinical trial on the use of medical Portland cement,MTA and calcium hydroxide in indirect pulp treatment

Objectives

Studies on indirect pulp treatment (IPT) show varying success rates of 73 to 97 %. The necessity of re-opening the cavity and the question of the optimal capping material is still under debate. The aim of this prospective in vivo study was to compare the clinical and microbiological outcomes of mineral trioxide aggregate (MTA), medical Portland cement, and calcium hydroxide on the dentin–pulp complex of permanent and primary teeth treated with two-step IPT.

Materials and methods

In 86 regular patients (51 % men; 49 % women; age 17.2 years ±13.8), one deep carious lesion each was treated with incomplete caries removal, randomly selected capping with either calcium hydroxide (n?=?31), medical Portland cement (29) or white MTA (26), and re-entry (6.3 months ±1.0). Clinical (color, humidity, and consistency of dentin) and microbiological (Lactobacilli/Mutans Strep. counts) parameters were recorded at the first and second treatment.

Results

The IPT had a high success rate of 90.3 % regardless of the material used (p?=?0.72). The arrested lesions showed consistently darker, dry, and therefore, sclerotic dentine (p?<?0.05) as well as a decrease in bacterial counts at re-entry (Lactobacilli p?=?0.01/Mutans Strep. p?=?0.07).

Conclusions

The findings of this study support the use of the IPT as a treatment for deep carious lesions preferably with non-resorbing materials such as MTA or medical Portland cement.

Clinical relevance

The findings of this study could promote the improvement of the IPT as a one-step treatment of deep carious lesions when the remaining demineralized dentin would be sealed with durable restorations.