Investigation of trefoil factor expression in saliva and oral mucosal tissues of patients with oral squamous cell carcinoma

Objectives

The aims of our study were to determine levels of trefoil factor (TFF) peptides in saliva and oral mucosal tissues from patients with oral squamous cell carcinoma (OSCC), and to evaluate whether individual members of TFFs (TFF1, TFF2, and TFF3) might act as biomarkers of disease.

Materials and methods

Saliva samples were from 23 healthy subjects and 23 OSCC patients. Tissue samples were collected from 32 normal oral mucosa (NOM) and 32 OSCC biopsy specimens. ELISA and immunohistochemical methods were used to evaluate the expression of TFF1, TFF2, and TFF3 in saliva and oral mucosal tissues, respectively.

Results

Expression of TFF2 and TFF3 in oral mucosal tissues of OSCC patients was strongly downregulated when compared to healthy subjects (p?<?0.001 and p?=?0.002, respectively). However, there were no differences in levels of salivary TFF concentrations between OSCC patients and healthy subjects.

Conclusions

The present study extends previous observations, demonstrating the reduction of TFF2 and TFF3 expression in oral mucosal tissues of OSCC patients.

Clinical relevance

These findings suggest the clinical significance of TFF2 and TFF3 molecules as negative markers of tumor progression in OSCC. Quantification of TFF levels in saliva may not be optimal in terms of diagnostic or predictive value for OSCC derived from oral mucosa.     

Increased immunoexpression of trefoil factors in salivary gland tumors

Objective

Very little is known about the role of trefoil factors (TFFs) in salivary gland tumors, and TFF immunoexpression has never been investigated in such tumors. The aim of this study was to evaluate TFF immunoexpression in benign and malignant salivary gland tumors.

Materials and methods

Benign (n?=?25) and malignant (n?=?25) salivary gland tumor specimens were included in this study, using mucocele (n?=?25) specimens as a control group. Immunohistochemical staining was performed to evaluate the expression of TFFs (TFF1, TFF2, and TFF3) by semiquantitative means.

Results

Expression of TFF1, TFF2, and TFF3 was significantly increased in benign (p?=?0.001, p?=?0.005, p?<?0.001, respectively) and malignant (p?<?0.001, p?<?0.001, p?<?0.001, respectively) groups as compared with the control group. Patterns of co-expression between TFF1/TFF2, TFF2/TFF3, and TFF1/TFF3 were different among the three groups.

Conclusions

The present study provided new information showing that all TFFs were significantly increased in benign and malignant salivary gland tumors, and overexpression of TFFs could be associated with neoplastic transformation in salivary gland tissues.

Clinical relevance

Overexpression of TFFs may be useful as biomarkers in terms of differential diagnosis between salivary gland tumors and other oral neoplasms for which clinical manifestations are indistinguishable.     

Salivary level of interleukin-8 in oral precancer and oral squamous cell carcinoma

Background

Interleukin 8 (IL-8) is a pro-angiogenic, pro-inflammatory mediator that belongs to the family of chemokines. Due to its pro-angiogenic characteristic, it may play a vital role in tumour angiogenesis and progression.

Objectives

This study was designed to estimate the levels of salivary IL-8 in oral precancer and oral squamous cell carcinoma (OSCC) patients and compare them with healthy controls. The aim was to evaluate its efficacy as a potential biomarker for these diseases.

Materials and methods

Each group comprised 25 individuals. The salivary IL-8 levels were determined by enzyme-linked immunosorbent assay.

Results

The levels of salivary IL-8 were found to be significantly elevated in patients with OSCC as compared to the precancer group (p?<?0.0001) and healthy controls (p?<?0.0001). However, the difference in salivary IL-8 concentrations among the precancer group and controls was statistically non-significant (p?=?0.738).

Conclusions

Our results suggested that salivary IL-8 can be utilised as a potential biomarker for OSCC. Salivary IL-8 was found to be non-conclusive for oral premalignancy in this preliminary study. Hence, its possible role in transition from premalignancy to malignancy needs further research with larger sample sizes.

Clinical relevance

Saliva as a diagnostic biofluid offers a number of advantages over blood-based testing. The role of IL-8 in oral cancer if validated further by future research can provide an easy diagnostic test as well as a prognostic indicator for patients undergoing treatment. Therefore, if it’s role in tumourigenesis can be sufficiently assessed, it could open up new avenues to find out novel treatment modalities for oral cancer.     

Eosinophils may predict occult lymph node metastasis in early oral cancer

Objective

The aim of this study was to investigate whether tumor-associated tissue eosinophilia (TATE) in early oral squamous cell carcinoma (OSCC) would aid in predicting occult lymph node metastasis.

Patients and methods

Seventy-one patients undergoing elective neck dissection for T1 and T2 OSCC were evaluated for clinical features, prognosis, and TATE. The degree of TATE in OSCC was statistically analyzed in relation to the clinicopathological features, tumor invasion, occult lymph node metastasis, and survival using χ ² test and Kaplan–Meier method.

Results

Statistical analysis revealed that intense TATE was a significant feature (p?=?0.004) to predict occult lymph node metastasis in patients with early OSCC. All regional recurrences of the OSCC occurred in patients showing intense TATE.

Conclusions

These results suggest that intense TATE can be clinically used as a predictive factor for occult lymph node metastasis.

Clinical relevance

The presence of intense TATE is an adjunctive histopathological marker to reinforce the indication of elective neck dissection of the patients with early OSCC.     

Prognostic value of histamine H1 receptor expression in oral squamous cell carcinoma

Objectives

Overexpression of the histamine H1 receptor (H1R) has been described in a variety of tumor models, but experience in oral squamous cell carcinomas (OSCC) is not available. Current adjuvant treatment options for OSCC can be improved by the identification of new targets of therapy. Herein, we evaluated H1R expression in a large patient cohort of OSCC.

Materials and methods

H1R immunoexpression was evaluated in 191 cases of OSCC and two OSCC cell lines BICR56 and BICR3. Scanned images were digitally analyzed using ImageJ and the immunomembrane plug-in. The combined score of computer-assisted semiquantitative analysis was correlated with manually counted percentages of tumor cells by Kendall’s tau (т) correlation coefficient. Disease-free survival times were estimated using the Kaplan–Meier method and were compared by using the log-rank test. Multivariate analyses were performed using the Cox proportional hazards model.

Results

H1R was rarely expressed in OSCC but significantly related with advanced tumor stages (n?=?21/191, mean expression 63.5 % of cancer cells in positive tumor samples, 95 % confidence interval of the mean 53.5 to 73.6 %, p?=?0.006). Following univariate analysis, patients with H1R expression showed a significant poorer prognosis (p?=?0.0004). Multivariate analysis revealed H1R expression as an independent prognostic factor (p?=?0.0164). Expression of H1R in cancer cell lines was confirmed by specific staining of OSCC cell lines BICR56 and BICR3.

Conclusion

This is the first study focusing on H1R expression showing a significant poorer DFS rate in the H1R+ patient cohort. Based on these data, H1R activation may promote carcinogenesis in OSCC.

Clinical relevance

Investigation of H1R regulation and its antagonists shows a clear rationale for future supportive anticancer therapies in OSCCs.     

Effect of nonsurgical periodontal therapy and strict plaque control on preterm/low birth weight: a randomized controlled clinical trial

Objective

This randomized controlled clinical trial was carried out to assess the effect of comprehensive nonsurgical periodontal treatment and strict plaque control performed during pregnancy on the reduction of preterm and/or low birth weight rates (PTLBW).

Material and methods

Three hundred and three women were randomly allocated to receive periodontal treatment either during pregnancy (n?=?147, test group) or after delivery (n?=?156, control group). During pregnancy, the control group received only one session of supragingival scaling and oral hygiene instruction. In contrast, the test group received comprehensive periodontal treatment including multiple sessions of scaling and root planing, oral hygiene instructions, and frequent maintenance visits.

Results

At baseline, periodontal inflammation was observed in approximately 50% of sites and attachment loss affected <15% of sites. Compared to controls, women in the test group had significant reductions in the percentage of sites with plaque (48.5% vs. 10.3%, p?<?0.001), gingival bleeding (23.3% vs. 2.5%, p?<?0.001), calculus (21.3% vs. 4.1%, p?<?0.001), bleeding on probing (38.1% vs. 2.6%, p?<?0.001) and probing depth ≥3 mm (19.97% vs. ?2.45%, p?<?0.001). No significant differences were observed between the groups in the occurrence of PT (11.7% vs. 9.1%, p?=?0.57), LBW (5.6 % vs. 4.1%, p?=?0.59), and PTLBW (4.15% vs. 2.60%, p?=?0.53).

Conclusions

Comprehensive periodontal treatment and strict plaque control significantly improved periodontal health; however, no reduction of PTLBW rates was observed. Thus, remaining periodontal inflammation posttreatment cannot explain the lack of effect of periodontal treatment on PTLBW.

Clinical relevance

This study demonstrated that periodontal diseases may be successfully treated during pregnancy. Our results do not support a potential beneficial effect of periodontal treatment on PTLBW.     

Changes in mastication after an immediate loading implantation with complete fixed rehabilitation

Objective

This study aimed to measure modifications of mastication after immediate loading full-arch prosthesis (ILFAP) rehabilitation.

Materials and method

Fourteen patients were observed before and 6 months after ILFAP rehabilitation when masticating two natural, standardized foods (peanut and carrot) and three model foods with increasing hardness. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Chewing time (CT), number of chewing cycles (CC), and chewing frequency (CF) were video recorded. A self-assessment questionnaire for oral health-related quality of life [Geriatric Oral Health Assessment Index (GOHAI)] was also used.

Results

After ILFAP rehabilitation, the mean D50 values for carrot and peanuts were smaller [Repeated Model Procedures (RMP), F?=?41, p?<?0.001]. Mean CT and CC values recorded with the three model foods decreased, while CF increased regardless of the model food hardness (RMP, F?=?14, F?=?10, and F?=?11, respectively, p?<?0.001). The GOHAI score increased from 43?±?9 to 56?±?3 (t test, p?<?0.001).

Conclusion

ILFAP rehabilitation improves the ability to reduce the bolus particle size and the ability to discriminate between different food hardnesses in the 6 months post-surgery period.

Clinical relevance

This study encourages the clinical development of immediate loading implantation with a fixed full-arch prosthesis protocol.     

Oral lichen planus shows higher expressions of tumor suppressor gene products of p53 and p21 compared to oral mucositis. An immunohistochemical study

Objective

Oral lichen planus (OLP) has been speculated to be a chronic inflammatory disease with potential for malignant progression. The aim of this study was to establish a hypothesis on the difference between OLP and oral mucositis (OM) in terms of tumor suppressor gene expression.

Design

Computer based image analysis of immunohistochemical expressions of p53 and p21 was investigated in 18 samples of OLP, 10 normal oral epithelium (NOE), 10 oral squamous cell carcinoma (OSCC), 13 OM, 20 oral focal keratosis (OFK), and 30 samples of oral epithelial dysplasia (OED). Representative fields were digitized and analyzed.

Results

Using independent samples Student's t-test, p53 and p21 the mean percentages of positive nuclei (MPPN) of p53 (40.27%) and of p21 (39.98%) in OLP were significantly higher than that of NOE, OFK and OM (15.06%, 27.87%, 30.08% and 16%, 31.09%, 33.92% respectively, p < 0.001). MPPN of p53 in OLP was not different from that of mild OED (40.5%, p = 0.85) but lower than of moderate and severe OED, and OSCC (49.78%, 61.36%, 78.16% respectively; p < 0.001). MPPN of p21 in OLP was lower than that of moderate and severe OED, and OSCC (47.72%, 57.9%, 85.44% respectively; p < 0.001) but slightly higher than that of mild OED (39.86% p = 0.81).

Conclusions

As the expression of p53 and p21 in OLP was significantly higher than that of oral mucositis with no significant difference from mild epithelial dysplasia, OLP might need to be followed up and monitored more closely to detect early features of transformation, if any, compared to non-specific oral mucositis which needs no close follow-up.     

Assessment of oral cancer pain,anxiety, and quality of life of oral squamous cell carcinoma patients with invasive treatment procedure

Purpose

Depending on its stage on diagnosis, oral squamous cell carcinoma (OSCC) might cause excruciating pain and decreased quality of life. As for treatment, the treatment of OSCC might vary from chemotherapy to surgery. The objective of the current study was to assess the preoperative and postoperative oral cancer pain, anxiety, and quality of life of OSCC patients with invasive treatment procedure.

Methods

The current study was conducted by interviewing 21 (10 males; 11 females) patients who had been diagnosed with stage 3 and stage 4 OSCC and about to go through surgery at the inpatient ward of Surgical Oncology Department, Hasan Sadikin Hospital, Bandung, Indonesia. A preoperative and interview was conducted by using the Hospital Anxiety and Depression Scale (HADS), the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QOL)-C30, the shortened EORTC QOL Questionnaire for Oesophageal Cancer (OES)18, the visual analog scale (VAS), and the University of California San Francisco (UCSF) Oral Cancer Pain Questionnaire. All data were analyzed to evaluate the preoperative and postoperative effect.

Results

The current study showed a significant decrease of the postoperative oral pain (p?<?0.01) and anxiety level (p?<?0.01), while postoperative patient’ quality of life was significantly (p?<?0.01) increased.

Conclusion

Despite of the invasive procedure that might cause postoperative effect, OSCC patients in the current study showed a better quality of life after cancer removal.

     

Periodontal clinical and microbiological data in desquamative gingivitis patients

Objectives

A series of patients affected by desquamative gingivitis (DG) was investigated in order to evaluate relation patterns among clinical parameters relevant to plaque-induced periodontitis, periodontal microbiological data and the presence of DG lesions.

Patients and methods

Eight oral lichen planus (OLP) and four mucous membrane pemphigoid (MMP) patients were examined. Periodontal measurements (performed at six sites per tooth on all teeth) included probing depth (PD), gingival recession (REC), clinical attachment loss (CAL) and full-mouth plaque (FMPS) and bleeding (FMBS) scores; the presence and the exact location (site by site) of DG lesions were carefully recorded. Sub-gingival plaque samples were collected and examined by means of real-time PCR for the quantitative determination of the six most important marker organisms of periodontitis. Statistically significant differences and correlation of studied variables between DG-positive and DG-negative sites were investigated in MMP and OLP cases using Mann–Whitney test (p?<?0.05) and the Spearman rank correlation coefficient, respectively.

Results

OLP gingival lesions do not significantly affect CAL, although the presence of such lesions may reduce REC and increase PD and FMPS. MMP gingival lesions significantly worsened CAL and increased REC and FMPS. In both OLP and MMP cases, no significant difference was found between DG-positive and DG-negative sites as regards the relative percentage of the investigated species on the total bacterial load. Correlations between the presence of DG lesions and clinical parameters (CAL, PD, REC) were not significant (p?<?0.05). Significant correlations were found for the presence of gingival OLP lesions and Aggregatibacter actinomycetemcomitans (AA) and for the absence of gingival MMP lesions and AA.

Conclusions

These findings are not definitive, but highlight the need for further investigations of periodontal clinical and microbiological aspects of disorders causing DG in order to clarify their potential interference with plaque-related periodontitis.     

Effects of Hydrophilicity and Microtopography of Titanium Implant Surfaces on Initial Supragingival Plaque Biofilm Formation. A Pilot Study

Objective

The aim of the present pilot study is to investigate the effects of hydrophilicity and microtopography of titanium implant surfaces on initial supragingival plaque biofilm formation.

Materials and Methods

Test specimens were manufactured from commercially pure grade 2 titanium according to one of the following procedures: polished (P), acid-etched (A), chemically modified (mod) A (modA), sand-blasted large grit and A (SLA), and modSLA. Intraoral splints were used to collect an in vivo supragingival plaque biofilm in each group at 12, 24, and 48 h. Stained plaque biofilm (PB) areas (%) were morphometrically assessed.

Results

All groups exhibited significant increases of mean PB areas over time (p?<?0.001; respectively). Morphometrical analysis revealed the following mean PB areas: 12?h: SLA?=?modSLA?>?P?>?A?=?modA (p?<?0.001; respectively); 24?h: SLA?>?modSLA?=?P?>A?=?modA (p?<?0.001; respectively); 48h: SLA?=?modSLA?=?P?>A?=?modA (p?<?0.001; respectively).

Conclusions

Within the limits of a pilot study, it could be concluded that hydrophilicity had no apparent effect, while microtopography had a highly uneven and unpredictable influence on supragingival plaque biofilm formation.     

Load-bearing capacity of CAD/CAM milled polymeric three-unit fixed dental prostheses: Effect of aging regimens

Objective

This study tested the fracture load of milled and conventionally fabricated polymeric and glass-ceramic three-unit fixed dental prostheses (FDPs) after aging.

Materials and methods

FDPs were fabricated (N?=?1,050) from four computer-aided design and computer-aided manufacturing (CAD/CAM) resins: (1) AT (artBlock Temp); (2) TC (Telio CAD); (3) ZP (ZENO PMMA); (4) CT (CAD-Temp); two conventionally fabricated resins, (5) IES (integral esthetic press), (6) CMK (CronMix K), and a glass-ceramic (control) (7) PG (IMAGINE PressX). Specimens of each group were tested immediately after fabrication (n?=?15 per material). Seventy-five FDPs per material type were stored in artificial saliva (37°C) and 15 of them were randomly selected after aging (1, 7, 28, 90, and 180?days) for fracture load measurement. The remaining specimens (n?=?60 per material) were subjected to chewing simulation (×120.000–1.200.000, 49?N, 5°C/50°C). The data were analyzed using two-way and one-way ANOVA followed by Scheffé test.

Results

The interactions between FDP materials and aging time in both storage media showed a significant impact on the results (p?<?0.001). Among saliva storage groups, TC and ZP showed the highest, and PG the lowest fracture load (p?<?0.05). AT and CT were not affected from chewing simulation. TC, ZP, and AT presented the highest in ascending order (p?<?0.05), PG and CMK showed the lowest fracture load after chewing simulation (p?<?0.001).

Conclusions

Aging did not influence the fracture load of FDPs made of CAD/CAM resins. FDPs made of glass–ceramic showed significantly lower fracture load than those of all resin FDPs. Clinical relevance: Considering fracture load measurements, CAD/CAM resins tested could be alternative materials to glass–ceramic for FDP construction.     

Dentofacial characteristics of patients with rheumatoid arthritis

Objectives

The aims of this study are to evaluate the dentofacial morphology of patients with rheumatoid arthritis (RA) and to compare the morphological data with those of healthy age- and sex-matched control subjects.

Methods

Twenty-seven RA patients (mean age, 45.77?±?8.64 years) and 25 healthy subjects (mean age, 44.80?±?8.24 years) participated in this prospective study. Clinical and functional evaluations of the RA patients were assessed. The erythrocyte sedimentation rate, C-reactive protein level, rheumatoid factor level, and anti-citrullinated peptide antibodies (ACPA) titers of RA patients were determined, and DAS28 scores were calculated. Linear and angular measurements were performed on cephalometric tracings and condylar erosion was evaluated on lateral panoramic radiographs. Statistical comparison of the two groups was performed with an independent samples t test. Pearson correlation analysis was used to assess the relationship between the clinical and laboratory parameters.

Results

Based on DAS28 scores, no patient with RA was in the remission period, 3 patients had low, 23 had medium, and 1 had high disease activity. Sixteen (59.26 %) patients with RA had positive ACPA titers. Lateral cephalometric radiographs revealed statistically significant difference between the two groups for the measurement of U1–NA (millimeter; p?=?0.047), U1–NA (degrees; p?=?0.031), L1–NB (degrees; p?=?0.030), IMPA (L1–MP; p?=?0.001), interincisal angle (U1–L1; degrees; p?=?0.022) and midface length (Co–A; millimeter; p?=?0.033). A significant positive linear correlation was found between disease duration time and DAS28 scores (r?=?0.066, p?=?0.040).

Conclusions

Dentoalveolar effects of RA on dentofacial morphology are more significant than the skeletal effects. Future studies with larger sample sizes are required to evaluate the exact effects of RA on dentofacial morphology.

Clinical relevance

Clinicians should consider the fact that RA-associated dentoalveolar changes can be observed and may affect the orthodontic treatment process.     

Expression of immunoregulatory molecules PD-L1 and PD-1 in oral cancer and precancerous lesions: A cohort study of Japanese patients

Objective

An association of the programmed cell death-1 (PD-1) and its ligand PD-L1 with various types of malignant tumors has been established. This study aimed to investigate the role of the PD-L1/PD-1 pathway in oral squamous cell carcinoma (OSCC) and oral epithelial precursor lesions (OEPL).

Vomer flap for hard palate repair is related to favorable maxillary growth in unilateral cleft lip and palate

Objective

Vomer flap repair is assumed to improve maxillary growth because of reduced scarring in growth-sensitive areas of the palate. Our aim was to evaluate whether facial growth in patients with unilateral cleft lip and palate was significantly affected by the technique of hard palate repair (vomer flap versus two-flap).

Materials and methods

For this retrospective longitudinal study, we analyzed 334 cephalometric radiographs from 95 patients with nonsyndromic complete unilateral cleft lip and palate who underwent hard palate repair by two different techniques (vomer flap versus two-flap). Clinical notes were reviewed to record treatment histories. Cephalometry was used to determine facial morphology and growth rate. The associations among facial morphology at age 20, facial growth rate, and technique of hard palate repair were assessed using generalized estimating equation analysis.

Results

The hard palate repair technique significantly influenced protrusion of the maxilla (SNA: β?=??3.5°, 95 % CI?=??5.2-1.7; p?=?0.001) and the anteroposterior jaw relation (ANB: β?=??4.2°, 95 % CI?=??6.4-1.9; p?=?0.001; Wits: β?=??5.7 mm, 95 % CI?=??9.6-1.2; p?=?0.01) at age 20, and their growth rates (SNA p?=?0.001, ANB p?<?0.01, and Wits p?=?0.02).

Conclusions

The results suggest that in patients with unilateral cleft lip and palate, vomer flap repair has a smaller adverse effect than two-flap on growth of the maxilla. This effect on maxillary growth is on the anteroposterior development of the alveolar maxilla and is progressive with age. We now perform hard palate closure with vomer flap followed by soft palate closure using Furlow palatoplasty.

Clinical relevance

These findings may improve treatment outcome by modifying the treatment protocol for patients with unilateral cleft lip and palate.     

Health-related quality of life and depression in patients with dentofacial deformity

Introduction

Patients with dentofacial deformities present difficulties at work and in social adaptation. At the same time, they often appear depressed, and as a consequence, the psychosocial aspects of surgery play an important role. The aim of this study was to investigate the effects that depression causes in the quality of life of patients with dentofacial deformity.

Material and methods

Filthy patients were recruited 1 year before undergoing orthognathic surgery and correlated oral and general health with the presence and absence of depression. In order to accomplish this, these patients received an adapted questionnaires of quality of life and Beck Depression Inventory to fill out. Fisher's test was applied, with a significance level of 5 %. Intercooled Stata version 9.0 was used to analyze data.

Results

Among the eight domains of quality of life, there were three associated with depression status: vitality (p?<?0.001), social aspects (p?=?0.011), and mental health (p?=?0.008).

Discussion

There is growing interest in the impact of dentofacial deformity conditions on patients' quality of life. The scientific literature has discussed the social aspects of these deformities and showed that untreated patients had low self-esteem and suffered social restrictions before making the orthodontic and surgical treatments. This study concluded that the depression interferes significantly in vitality, social aspects of the individual, and mental health and, at the same time, emphasizes that the orthognathic surgery aims to not only restore esthetics and function to the patient but also improve the quality of life.     

The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio

Objective

This study investigated the effect of sintering temperatures on flexural strength, contrast ratio, and grain size of zirconia.

Materials and Methods

Zirconia specimens (Ceramill ZI, Amann Girrbach) were prepared in partially sintered state. Subsequently, the specimens were randomly divided into nine groups and sintered with different final sintering temperatures: 1,300°C, 1,350°C, 1,400°C, 1,450°C, 1,500°C, 1,550°C, 1,600°C, 1,650°C, or 1,700°C with 120 min holding time. Three-point flexural strength (N?=?198; n?=?22 per group) was measured according to ISO 6872: 2008. The contrast ratio (N?=?90; n?=?10 per group) was measured according to ISO 2471: 2008. Grain sizes and microstructure of different groups were investigated (N?=?9, n?=?1 per group) with scanning electron microscope. Data were analyzed using one-way ANOVA with Scheffé test and Weibull statistics (p?<?0.05). Pearson correlation coefficient was calculated between either flexural strength or contrast ratio and sintering temperatures.

Results

The highest flexural strength was observed in groups sintered between 1,400°C and 1,550°C. The highest Weibull moduli were obtained for zirconia sintered at 1,400°C and the lowest at 1,700°C. The contrast ratio and the grain size were higher with the higher sintering temperature. The microstructure of the specimens sintered above 1,650°C exhibited defects. Sintering temperatures showed a significant negative correlation with both the flexural strength (r?=??0.313, p?<?0.001) and the contrast ratio values (r?=??0.96, p?<?0.001).

Conclusions

The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength.

Clinical Relevance

Considering the flexural strength values and Weibull moduli, the sintering temperature for the zirconia tested in this study should not exceed 1,550°C.     

Use of ultrasonic scalpel and monopolar electrocautery for skin incisions in neck dissection: a prospective randomized trial

Purpose

Ultrasonic scalpel (UC) and monopolar electrocautery (ME) are standard equipment for soft tissue surgery. The aim of the present study was to compare intraoperative and postoperative patterns of patients using either UC or ME for skin incisions in neck dissection.

Material and methods

In a prospective randomized study of 30 patients, the thermal effects of UC (n?=?15) and ME (n?=?15) were examined using real-time infrared thermographic imaging. Additionally, tissue damage was evaluated histopathologically. The other measured variables were operation and bleeding time, postoperative pain score (only neck incision area), in-patient time, and complications.

Results

UC significantly reduces the thermal effects, compared to ME (p?<?0.001). The mean depth of tissue damage (i.e., necrosis) was 272.7 μm for UC and 284.7 μm for ME with no significant difference (p?=?0.285). From the third postoperative day, patients treated using UC had noticeably less pain in the neck incision area (t3 p?=?0.010; t4 p?<?0.001; t5 p?<?0.005). Cutting time was reduced for ME by 36.1 s (p?<?0.001) and the bleeding time was decreased by 40.9 s for UC (p?<?0.001). The total preparation time was the same (p?=?0.402). When comparing in-patient time (p?=?0.723), as well as complications, no significant differences were seen.

Conclusion

UC results in less postoperative pain and less bleeding in the neck incision area. Accordingly, UC is superior to ME for skin incisions in neck dissection.