Transdentinal cytotoxicity of resin-based luting cements to pulp cells

Objectives

The aim of this study was to evaluate the transdentinal cytotoxicity of components released from different resin-based luting cements to cultured MDPC-23 odontoblast-like cells and human dental pulp cells (HDPCs).

Materials and methods

Artificial pulp chamber (APC)/dentin disc sets were distributed into four groups according to the materials tested (n = 10), as follows: G1, control (no treatment); G2, resin-modified glass-ionomer cement (RelyX Luting 2); G3, self-adhesive resin cement (RelyX U200); and G4, conventional resin cement (RelyX ARC). The materials were applied to the occlusal surfaces (facing up) of the dentin discs adapted to the APCs. The pulpal surfaces of the discs were maintained in contact with culture medium. Then, an aliquot of 400 μL from the extract (culture medium + resin-based components that diffused through dentin) of each luting cement was applied for 24 h to HDPCs or MDPC-23 cells previously seeded in wells of 24-well plates. Cell viability analysis was performed by the MTT assay (1-way ANOVA/Tukey test; α = 5 %).

Results

For MDPC-23 cells, RelyX ARC (G4) and RelyX Luting 2 (G2) caused greater reduction in cell viability compared with the negative control group (P < 0.05). Only the HDPCs exposed to RelyX ARC (G4) extract showed a tendency toward viability decrease (9.3 %); however, the values were statistically similar to those of the control group (G1) (P > 0.05).

Conclusions

In accordance with the safe limits of ISO 10993-5:1999 (E) recommendations, all resin-based luting cements evaluated in this study can be considered as non-toxic to pulp cells.

Clinical relevance

Cytotoxicity of resin-based luting cements is material-dependent, and the different protocols for the application of these dental materials to dentin may interfere with their cytotoxicity.

     

The prognostic value of histopathology on lingual nerve neurosensory recovery after micro-neurosurgery

Objective

Micro-neurosurgical repair is considered in permanent nerve damage but the outcome is unpredictable. We examined if histopathologic parameters of traumatic neuromas have a prognostic value for recovery in relation to lingual nerve micro-neurosurgery.

Materials and methods

Retrospective case study on neurosensory recovery after micro-neurosurgery. Outcome variables were as follows: pain perception, two-point discrimination, and sum score of perception, before and 12 months after micro-neurosurgery. Predictive histopathology variables included size, nerve tissue, and inflammation. Statistics are as follows: logistic and correlation analyses (P < 0.05).

Results

Sixty-five patients with lingual nerve damage were included in the study. Improved two-point discrimination was associated with small size of resected tissue (P = 0.0275). No normal appearing distal nerve tissue was associated with improved sum score of perception (P = 0.0185), higher final sum score of perception value (P = 0.0475) and final pain perception (P = 0.0324). Foreign body reaction was associated with no final pain perception (P = 0.0492).

Conclusions

Small size, absence of distal nerve tissue, and no foreign body reaction were associated with improvement of the neurosensory functions.

Clinical relevance

Histological parameters of the traumatic neuromas in routine preparation appeared to have some prognostic value for neurosensory functions as improvement of the neurosensory functions was associated with small size of resected tissue, no distal normal appearing nerve tissue, and no foreign body reaction.

     

Impact of different adhesives on work of adhesion between CAD/CAM polymers and resin composite cements

Objective

To determine the impact of pre-treatment of adhesive systems on the work of adhesion (WA) between CAD/CAM polymers and resin composite cements and compare with conventional tests of previous studies.

Methods

Surface parameters were measured by contact angle measurement (2700 measurements) and WA was calculated. Five CAD/CAM polymers were used for fabrication of specimens (n = 75/subgroup): artBloc Temp (A), Telio CAD (B), Nano Composite CFI-C (C), exp. CAD/CAM nanohybrid composite (D), and LAVA Ultimate (E). Then, air-abraded specimens were pre-treated (n = 15 per group): Ambarino P60 (I), Monobond Plus/Heliobond (II), visio.link (III), VP connect (IV), and no pre-treatment (V). Resin composite cement specimens (n = 75) were smoothed out homogeneously on a glass plate (n = 15/group): RelyX ARC (RXA), Variolink II (VAR), Panavia F2.0 (PAN), RelyX Unicem (RXU), and Clearfil SA Cement (CSA). Contact angles were determined with 3 drops of distilled water and diiodomethane each. Data were analyzed using Kruskal–Wallis-H test and Spearman-Rho correlation (p < 0.05).

Results

CAD/CAM materials (B), (A), and (C) showed higher WA compared to (D) and (E). (II) and (IV) resulted in higher WA than (I), (III) and (V). VAR had the significantly lowest WA, followed by RXU, RXA, CSA and PAN. No correlation occurred between WA and TBS/SBS whereas polar component of surface free energy of CAD/CAM resin and spreading coefficient showed significant positive correlation with TBS/SBS.

Conclusions

Determination of WA is not a proper method to draw conclusions about the bond between resin materials. Destructive test methods are not dispensable.

Clinical significance

The successful outcome of fixed dental restorations depends, among others, on the quality of bonding between the tooth and the restoration. Additional pre-treatment of the dental CAD/CAM resin restoration by bonding systems can be recommended for clinical use. Pre-treatment showed a significant impact on the surface properties.     

Effect of ultrasonic tip and root-end filling material on bond strength

Objectives

The objective of this study was to evaluate the bond strength of three root-end filling materials (MTAA–MTA Angelus, MTAS–experimental MTA Sealer, and ZOE- zinc oxide and eugenol cement) in retrograde preparations performed with different ultrasonic tips (CVD, Trinity, and Satelec).

Materials and method

Ninety 2-mm root sections from single-rooted human teeth were used. The retrograde cavities were prepared by using the ultrasonic tips, coupled to a device for position standardization. The specimens were randomly divided into nine groups: CVD MTAA; CVD MTAS; CVD ZOE; Trinity MTAA; Trinity MTAS; Trinity ZOE; Satelec MTAA; Satelec MTAS; Satelec ZOE. Each resin disc/dentin/root-end filling material was placed in the machine to perform the push-out test. The specimens were examined in a stereomicroscope to evaluate the type of failure. Data were submitted to statistical analysis using ANOVA and Tukey tests (α?=?0.05).

Results

The highest bond strength was observed for the CVD tip irrespective of the material used (P?<?0.05). There was no significant difference for the Trinity TU-18 diamond and S12 Satelec tips (P?>?0.05). MTAA and MTAS showed highest bond strength. The most common type of failure was adhesion between the filling material and dentin wall, except for ZOE, where mixed failure was predominant.

Conclusions

The CVD tip favored higher bond strength of the root-end filling materials. MTA Angelus and experimental MTAS presented bond strength to dentin prepared with ultrasonic tips.

Clinical relevance

Root-end preparation with the CVD tip positively influences the bond strength of root-end filling materials. MTA Angelus and experimental MTAS present bond strength to be used as root-end filling materials.

     

Four-year randomized clinical trial of oxalic acid pretreatment in restorations of non-carious cervical lesions

Objective

The aim of this study was to evaluate the efficiency of oxalic acid (BisBlock) on restorations of non-carious cervical lesions.

Materials and methods

One operator placed 90 restorations randomly divided into two groups in 20 patients under cotton rolls isolation: Control Group—two-step etch-and-rinse adhesive technique; and Experimental Group—two-step etch-and-rinse adhesive technique with oxalic acid pretreatment after acid-etched dentin. The restorative adhesive system used was XP Bond/Durafill. The restorations were directly assessed by two independent examiners, using the modified United States Public Health Service (USPHS) criteria at the baseline and 4 years. Data were statistically analyzed using the Fisher and McNemar tests (p < 0.05).

Results

Fifteen patients (75 %) were available for recall after 4 years. The McNemar test detected significant differences within the Experimental Group between the baseline and 4-year evaluations for retention (p < 0.05). For the Control Group, there was no significant difference (p > 0.05) between the periods. The Fisher test showed no statistically significant difference between the groups for all other criteria (p > 0.05).

Conclusion

After 4 years of service, the use of oxalic acid did not influence the clinical performance of restorations when it was used under composite resin restorations.

     

Prevalence of <Emphasis Type="Italic">Candida albicans</Emphasis> and <Emphasis Type="Italic">Candida dubliniensis</Emphasis> in caries-free and caries-active children in relation to the oral microbiota—a clinical study

Objectives

The correlation between caries and the oral prevalence of Candida spp. in children is contradictory in literature. Thereby, authors focused on Candida albicans as the most isolated Candida species from the oral cavity. Therefore, the aim of the present study was to compare caries-free and caries-bearing children regarding their oral carriage of Candida spp.

Material and methods

Twenty-six caries-free (CF group) and 26 caries-active children (CA group) were included into this study. Three different types of specimens were assessed, saliva and plaque, and in the case of caries, infected dentine samples were microbiologically analyzed for aerobic and anaerobic microorganisms and their counts. Special attention was given to the differentiation between C. albicans and Candida dubliniensis. Additionally, different biochemical tests, VITEK 2 (VITEK®2, bioMérieux, Marcy-l’Etoile, France) and 16S and 18S ribosomal DNA (rDNA) sequencing, were applied for identification.

Results

The detection of C. albicans did not differ between the CF and CA groups. C. dubliniensis was never detected in any specimen of the CF group, but occurred in one quarter of the CA group (27 % in plaque, 23 % in saliva), thus leading to a statistically significant difference between the two groups (p < 0.05). In six of these cases, C. dubliniensis was detected concomitantly in saliva and plaque and once only in plaque. CA group harbored statistically more Streptococcus mutans than the control group revealing a correlation between S. mutans and C. dubliniensis regarding the caries group.

Conclusions

This is the first study reporting a frequent detection of C. dubliniensis in caries-active children, which could have been underestimated so far due to difficulties in differentiation between this yeast species and C. albicans.

Clinical relevance

Microbiological diagnostic—especially of oral Candida species—is an important determinant for identifying etiological factors of dental caries in children.

     

Cementoblastic lineage formation in the cross-talk between stem cells of human exfoliated deciduous teeth and epithelial rests of Malassez cells

Objectives

The purpose of this study was to evaluate the synergistic effect of epithelial rests of Malassez cells (ERM) and transforming growth factor-β₁ (TGF-β₁) on proliferation, cementogenic and osteogenic differentiation of stem cells derived from human exfoliated deciduous teeth (SHED).

Materials and methods

SHED were co-cultured with ERM with/without TGF-β₁. Then, SHED proliferation, morphological appearance, alkaline phosphatase (ALP) activity, mineralization behaviour and gene/protein expression of cemento/osteoblastic phenotype were evaluated.

Results

TGF-β₁ enhanced SHED proliferation when either cultured alone or co-cultured with ERM. ERM induced the cementoblastic differentiation of SHED which was significantly accelerated when treated with TGF-β₁. This activity was demonstrated by high ALP activity, strong mineral deposition and upregulation of cementum/bone-related gene and protein expressions (i.e. ALP, collagen type I, bone sialoprotein, osteocalcin and cementum attachment protein).

Conclusions

ERM were able to induce SHED differentiation along the cemento/osteoblastic lineage that was triggered in the presence of TGF-β₁.

Clinical relevance

The cemento/osteoblastic differentiation capability of SHED possesses a therapeutic potential in endodontic and periodontal tissue engineering.

     

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.

     

Characterization and Antibiotic Sensitivity Profile of Bacteria in Orofacial Abscesses of Odontogenic Origin

Background

Odontogenic infections range from peripheral abscess to superficial and deep infections leading to severe infections in head and neck region. This study was aimed to assess bacterial isolates responsible for orofacial infection of odontogenic origin and their drug susceptibility patterns so as to provide better perceptive for the management of odontogenic infections.

Methods

The study was made in a selected cohort of patients, irrespective of age and gender having moderate and severe orofacial infections of odontogenic origin admitted to Yenepoya University Hospital. Pus samples were collected and identification of bacteria was performed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method.

Result

A total of 37 study subjects were included, with bacterial isolation rate of 31 (83.7 %). The mean age presented of all patients was 40.62. Of all, 24 (64.9 %) were males. Staphylococcus aureus, Enterobacter claocae subsp. dissolvens, Klebsiella quasipneumoniae subsp. similipneumoniae, Staphylococcus aureus subsp. anaerobius and Klebsiella pneumoniae subsp. ozaenae were the most prevalent isolates. Result showed that 58.6 % of the isolates were resistant to gentamicin, 52.5 % for ampicillin, 51.3 % for piperacillin; least resistant being 18.9 % for azithromycin.

Conclusion

High prevalence of bacterial isolates was found, Staphylococcus aureus being the dominant. Most of the bacteria were resistant to different classes of antibiotics. Appropriate antibiotics should be given based on the bacterial isolates, culture sensitivity and clinical course of the disease.

     

Detection of artificial demineralization bordering different types of laminate veneers using visual inspection and storage phosphor radiography

Objective

The objective of this study is to compare the diagnostic accuracy of visual inspection (VI) and storage phosphor plate (SPP) radiography for the detection of artificial demineralization bordering different laminate veneers.

Materials and methods

Twenty human maxillary canine teeth were prepared. All-ceramic (A) and hybrid ceramic (H) laminate veneers were fabricated and luted. Veneered teeth were covered except for a circular window on the proximal surface bordering restorations. Teeth were kept in acetic acid buffer to create demineralization and imaged with a SPP system. Ten observers evaluated all teeth first visually then with SPP images for the presence/absence of demineralization. Teeth were examined using scanning electron microscopy (SEM) as well. The accuracy was expressed as the area under the ROC curves (A _z). Pair-wise comparisons were performed using two-way ANOVA and post hoc t test (p?=?0.05). Fleiss kappa (κ) was used for agreement.

Results

SPP radiography was better than the VI for both veneers (p?=?0.004). The A _zs of two veneers were different for both VI (p?<?0.005) and SPP (p?<?0.005). SEM evaluation revealed lesions confined to enamel. κ was fair for H, and fair to moderate for A. Agreement was higher for the radiographic evaluation for both veneers.

Conclusion

Enamel demineralizations bordering hybrid and ceramic laminate veneers can be detected better with SPP radiography than VI and detectability was better for all-ceramic veneers than the hybrid ceramic ones.

Clinical relevance

Early detection of enamel demineralizations bordering laminate veneers would result in time-saving and less-invasive treatment methods; therefore, SPP radiography may be recommended in clinically suspicious cases since it provides better diagnostic accuracy.

     

Electronic central bearing point as registration method in individuals with and without temporomandibular disorders

Objectives

The aim of this study was to examine different central bearing point methods in patients with and without temporomandibular disorders (TMD) by an experienced and unexperienced examiner.

Material and methods

The 20 fully dentulous subjects were screened for TMD based on the Research Diagnostic Criteria for TMD and distinguished into functional impaired and functional healthy groups. The mandibular relationship was recorded by an electronic central bearing tracing device (IPR-System, IPR GmbH, Oldenburg, Germany) with an integrated pressure sensor. Three bite registration methods were performed using this device: initial neuromuscular position, final neuromuscular position after dynamic sequences with the intraoral pin (=neuromuscular deprogramming), and centric relation guided manually by an experienced and an unexperienced examiner.

Results

The neuromuscular positions before and after neuromuscular deprogramming were not significantly different (paired t test as a group comparison test: transverse: p = 0.369; sagittal: p = 0.486). Both positions were significantly anterior in comparison to the manually guided centric relation (paired t test as a group comparison test: p < 0.0001). The neuromuscular positions before and after deprogramming tend to have high scattering values.

Conclusion

By means of the central bearing point method, the manually guided centric relation is the one which is sufficiently reproducible. It seems doubtful to take the significant anterior neuromuscular position for a definite reconstruction.

Clinical relevance

Using the central bearing point method, the manually guided centric relation should be preferred, whereas the neuromuscular position should not be used for definite reconstructions.

     

Increased local recurrence in advanced parotid malignancy treated with mastoidectomy without lateral temporal bone resection

Objective

We analyzed patients with advanced parotid malignancy requiring proximal facial nerve exposure undergoing mastoidectomy versus lateral temporal bone resection to determine differences in local and distant recurrence.

Study design

The study design is a case series with chart review.

Setting

The setting is in Tertiary care practice in Fort Worth, Texas from January1998 to January 2014.

Subjects and methods

The study included 120 patients with advanced parotid malignancy, 82 males between 19 and 87 years, and 38 females between 26 and 83 years. Patients with no overt bone involvement were treated with parotidectomy and mastoidectomy for exposure of the proximal facial nerve, and patients with clinically suspected (radiographic imaging or clinical fixation) bone involvement were treated with parotidectomy and lateral temporal bone resection. Follow up ranged from a minimum of 18 months to 11 years following surgery.

Results

Sixty patients were treated with mastoidectomy and 60 were treated with lateral temporal bone resection. In patients treated with mastoidectomy, 13 had local recurrence and 7 had distal recurrence. In patients treated with lateral temporal bone resection, 2 had local recurrence while 9 had distant recurrence. Statistical analysis revealed that patients treated with mastoidectomy developed local recurrence (p = 0.0022) more commonly than those treated with lateral temporal bone resection. There was no significant difference in distant recurrence between both groups (p = 0.5949).

Conclusions

Patients with advanced parotid malignancy should be treated aggressively with parotidectomy and lateral temporal bone resection regardless of bone involvement due to increased risk of local recurrence in those treated with mastoidectomy alone.

Level of evidence

Level of evidence is a 4 case series.

     

Association of vdr,cyp27b1, cyp24a1 and mthfr gene polymorphisms with oral lichen planus risk

Objectives

The current study investigated the association between VDR EcoRV (rs4516035), FokI (rs2228570), ApaI (rs7975232) and TaqI (rs731236), CYP27B1 (rs4646536), CYP24A1 (rs2296241), and MTHFR (rs1801133) gene polymorphisms and risk of oral lichen planus (OLP) occurrence.

Materials and methods

The study group consisted of 65 oral lichen planus patients and 100 healthy blood donors in the control group. Single nucleotide polymorphisms were genotyped by real time PCR or PCR-restriction fragment length polymorphism (RFLP) method.

Results

Heterozygous as well as mutated genotype of vitamin D receptor (VDR) FokI (rs2228570) polymorphism was associated with increased oral lichen planus risk in comparison with wild type genotype (odds ratio (OR) = 3.877, p = 0.017, OR = 38.153, p = 0.001, respectively). A significantly decreased OLP risk was observed for heterozygous genotype of rs2296241 polymorphism in CYP24A1 gene compared with the wild type form (OR = 0.314, p = 0.012). VDR gene polymorphisms ApaI and TaqI were in linkage disequilibrium (D’ = 0.71, r ² = 0.22). Identified haplotype AT was associated with decreased OLP risk (OR = 0.592, p = 0.047).

Conclusion

Our results highlight the possible important role of VDR FokI (rs2228570) and CYP24A1 rs2296241 gene polymorphisms for oral lichen planus susceptibility.

Clinical relevance

Identification of new molecular biomarkers could potentially contribute to determination of individuals with OLP predisposition.

     

Citrullination in the periodontium—a possible link between periodontitis and rheumatoid arthritis

Objectives

The aim of the present study was to assess human and bacterial peptidylarginine deiminase (PAD) activity in the gingival crevicular fluid (GCF) in the context of serum levels of antibodies against citrullinated epitopes in rheumatoid arthritis and periodontitis.

Materials and methods

Human PAD and Porphyromonas gingivalis-derived enzyme (PPAD) activities were measured in the GCF of 52 rheumatoid arthritis (RA) patients (48 with periodontitis and 4 without) and 44 non-RA controls (28 with periodontitis and 16 without). Serum antibodies against citrullinated epitopes were measured by ELISA. Bacteria being associated with periodontitis were determined by nucleic-acid-based methods.

Results

Citrullination was present in 26 (50 %) RA patients and 23 (48 %) controls. PAD and PPAD activities were detected in 36 (69 %) and 30 (58 %) RA patients, respectively, and in 30 (68 %) and 21 (50 %) controls, respectively. PPAD activity was higher in RA and non-RA patients with periodontitis than in those without (p = 0.038; p = 0.004), and was detected in 35 of 59 P. gingivalis-positive samples, and in 16 of 37 P. gingivalis-negative samples in association with high antibody levels against that species.

Conclusions

PAD and PPAD activities within the periodontium are elevated in RA and non-RA patients with periodontitis. PPAD secreted by P. gingivalis residing in epithelial cells may exert its citrullinating activity in distant regions of the periodontium or even distant tissues.

Clinical relevance

In periodontitis, the citrullination of proteins/peptides by human and bacterial peptidylarginine deiminases may generate antibodies after breaching immunotolerance in susceptible individuals.

     

A new method for the evaluation of the accuracy of full-arch digital impressions in vitro

Objectives

Introducing a new approach to evaluate the accuracy of digital impression methods for full-arch scans, avoiding “best-fit alignment.”

Materials and methods

A lower jaw model with a straight metal bar between the second molars of both quadrants was directly digitized using an intraoral scanner (True Definition, TRD, n?=?12) and indirectly digitized (D810, CON, n?=?12) after impression and plaster cast. A dataset of the bar from a coordinate measuring machine served as reference (REF). Datasets obtained from test groups were analyzed using inspection software to determine the aberration of the bar length, the linear shift (in X-, Y-, Z-axis) and the angle deviation (α _overall, α _coronal, α _horizontal) caused by the digitalization method. Mann–Whitney U and unpaired two-sample Student’s t test were implemented to detect differences. The level of significance was set at 5 %.

Results

Concerning the bar length, no significant differences were found between groups. In view of the linear shift, CON showed significantly higher values than TRD in Y-axis (p?=?0.003) and in Z-axis (p?=?0.040). Regarding the angle measurement, TRD showed significant smaller values than CON for α _overall (p?=?0.006) and for α _coronal (p?=?0.005).

Conclusions

This in vitro study shows that intraoral scanning systems seem to show the same or even higher accuracy than the conventional impression with subsequent indirect digitalization.

Clinical relevance

Intraoral scanners have proven excellent accuracy for single teeth or small spans. However, insufficient data is available about their accuracy for full-arch scans. The presented new approach seems to be suitable to precisely analyze differences in the accuracy of different digitalization methods without using best-fit alignment.

     

Comparison between primary closure and skin grafts of the free fibula osteocutaneous flap donor site

Purpose

This study aimed to compare the size of skin paddles, the postoperative course, and donor site complications between primary closure and skin grafts of the free fibula flap donor site.

Methods

Thirty-five consecutive patients were enrolled. Medical records were retrospectively reviewed for risk factors for delayed healing, size of skin paddles, time to resumption of gait with a mobility aid and self-ambulation, early donor site morbidity, and late donor site complaints.

Results

The harvested skin paddles were significantly wider in the skin graft group than in the primary closure group (P?=?0.02), with no difference in length (P?=?0.1). The difference in time to resuming gait with a mobility aid was also significant (P?=?0.01), but not the time to self-ambulation (P?=?0.9). Two early donor site morbidities (5.7 %) and 12 late donor site complaints (34.3 %) were found. No significant difference in the incidence of early donor site morbidity was observed between two groups. Occurrence of late donor site complaints was not affected by any risk factors.

Conclusions

The width of the harvested skin paddle, but not the length, is one of factors involved in donor site closure. Resumption of gait with a mobility aid, but not self-ambulation, may be delayed in skin graft patients.

     

Zinc-modified nanopolymers improve the quality of resin–dentin bonded interfaces

Introduction

Demineralized collagen fibers at the hybrid layer are susceptible to degradation. Remineralization may aid to improve bond longevity.

Objectives

The aim of the present study was to infiltrate zinc and calcium-loaded polymeric nanoparticles into demineralized dentin to facilitate hybrid layer remineralization.

Materials and methods

Zinc or calcium-loaded polymeric nanoparticles were infiltrated into etched dentin, and Single Bond Adhesive was applied. Bond strength was tested after 24 h and 6 months storage. Nanomechanical properties, dye-assisted confocal laser microscopy, and Masson’s trichrome staining evaluation were performed to assess for the hybrid layer morphology, permeability, and remineralization ability after 24 h and 3 months. Data were analyzed by ANOVA and Student–Newman–Keuls multiple comparisons tests (p < 0.05).

Results

Immediate bond strength was not affected by nanoparticles infiltration (25 to 30 MPa), while after 6 months, bond strengths were maintained (22 to 24 MPa). After 3 months, permeability occurred only in specimens in which nanoparticles were not infiltrated. Dentin remineralization, at the bottom of the hybrid layer, was observed in all groups. After microscopy analysis, zinc-loaded nanoparticles were shown to facilitate calcium deposition throughout the entire hybrid layer. Young’s modulus at the hybrid layer increased from 2.09 to 3.25 GPa after 3 months, in specimens with zinc nanoparticles; meanwhile, these values were reduced from 1.66 to 0.49 GPa, in the control group.

Conclusion

Infiltration of polymeric nanoparticles into demineralized dentin increased long-term bond strengths. Zinc-loaded nanoparticles facilitate dentin remineralization within the complete resin–dentin interface.

Clinical relevance

Resin–dentin bond longevity and dentin remineralization at the hybrid layer were facilitated by zinc-loaded nanoparticles.

     

Analysis of the blood supply to the post-fracture edentulous mandible: study by colour Doppler sonography

Purpose

This study assessed the arterial blood supply to the mandible of edentulous patients treated for mandibular fractures using colour Doppler ultrasound.

Methods

The blood supply of edentulous patients surgically treated for mandibular fractures (group A) and edentulous fracture-free individuals (group B) was assessed. Only the fractured sides were evaluated in the first group (N?=?17), whereas each side was evaluated in the second group (N?=?20). The arterial flow of six sites was assessed. The systolic-peak maximum velocity (SPV), final diastolic velocity (FDV), resistive index (RI), pulsatility index (PI), acceleration and flow direction of each artery were obtained. Additionally, the presence of local vascular obstructive factors was evaluated. The differences between groups were analysed using the Kruskal-Wallis test, which was complemented by the Mann-Whitney test, for correlations between the degree of alveolar atrophy and the study factors (p?<?0.050).

Results

There was a significant decrease in the flow of certain arteries, especially the submental (SPV, p?=?0.007, PI, p?=?0.022, and acceleration, p?=?0.015), in the fracture group. The facial artery in both groups showed lower values related to local obstructive factors (SPV, p?=?0.001, FDV, p?=?0.040, and PI, p?=?0.030). The submental artery flow was higher (SPV, p?=?0.006, and FDV, p?=?0.009) in non-atrophic individuals.

Conclusions

There was a decreased flow mainly in the submental artery, but there were no cases of major vascular injury in edentulous patients treated for mandibular fractures.

     

Internal derangement in the temporomandibular joint of juveniles with clinical signs of TMD

Aim

The aim of this study was to investigate possible correlation of specific skeletal or dental class in children and adolescents with clinical signs of temporomandibular dysfunction (TMD) with the severity of internal derangement (ID) of the temporomandibular joint.

Materials and methods

Based on MRI images, the ID of 232 juvenile temporomandibular joints in 116 patients were retrospectively recorded. The distribution of the ID stages within the skeletal and dental classes was compared by means of the χ ² test.

Results

Excluding the comparison between skeletal Class I (S I) and skeletal Class II (S II; p < 0.05), no statistically significant differences in the distribution of the ID stages were found between the skeletal classes (p > 0.05). No statistically significant differences were found when comparing the distribution of the ID stages between the dental classes (p > 0.05).

Conclusion

According to these findings, there is no skeletal or dental class that is related to higher degrees of internal derangement in the TMJs of children and adolescents presenting clinical signs of TMD. Therefore, it is not possible to draw conclusions about the severity of the ID in relation to the dental and skeletal class in symptomatic juvenile TMJs.

     

The role of elective superficial parotidectomy in the treatment of temporal region squamous cell carcinoma

Objective

In order to determine rates of metastasis and efficacy of elective superficial parotidectomy, we examine parotid specimens in patients with temporal region cutaneous squamous cell carcinoma treated with local excision and ipsilateral parotidectomy.

Study design

This paper is a retrospective review.

Setting

This study was conducted at a private tertiary referral practice in Fort Worth, Texas, from 1998 to 2013.

Subjects and methods

Ninety-three patients between ages 27 and 98 with primary squamous cell carcinoma of the temporal region greater than or equal to 2 cm were included in this study. Subjects had no evidence of adenopathy or parotid involvement on exam or imaging. Patients were treated with local excision and ipsilateral parotidectomy. The primary tumor was studied for vascular involvement and perineural invasion while the parotid specimen was analyzed for occult cancer. Patients were post-operatively followed for a minimum of three years.

Results

Twenty-three (24.7 %) parotid samples were found to harbor occult malignancy. Of these, nine (39.1 %) patients had vascular involvement of the primary tumor and 14 (60.8 %) had perineural invasion. Thirteen out of 58 affected males and 10 out of 35 affected females were found to have intraparotid node positivity. Vascular involvement (p?=?0.0004) and perineural invasion (p?=?0.0001) in the primary malignancy were found to be greater in patients with positive specimen. Sex was not statistically significant.

Conclusions

In patients with cutaneous squamous cell carcinoma of the temporal region at least 2 cm in size, elective superficial parotidectomy may be a beneficial part of treatment, especially in primary tumors showing perineural and/or vascular involvement.

Level of evidence

Level 2b (retrospective cohort)