A comparison of the prevalence of respiratory pathogens and opportunistic respiratory pathogenic profile of 'clean' and 'unclean' removable dental prostheses

OBJECTIVES

To determine and compare the opportunistic respiratory pathogenic index (ORPI) and prevalence of respiratory pathogens between clean and unclean removable prostheses.

METHODS

A cross-sectional study was conducted among 97 removable prosthesis wearers at a teaching dental hospital. Participants' prosthesis hygiene was grouped into clean and unclean. After prosthesis plaque samples were sequenced using the Type IIB Restriction-site Associated DNA Sequencing for Microbiome method, the prevalence was assessed for the presence of respiratory pathogens on each sample. The ORPIs for clean and unclean prostheses were quantified based on the sum of the relative abundance of respiratory pathogenic bacteria in a microbiome using a reference database that contains opportunistic respiratory pathogens and disease-associated information.

RESULTS

A total of 30 opportunistic respiratory pathogens were identified on the removable prostheses. Eighty-one (83.5 %) removable prostheses harboured respiratory pathogenic bacteria. Stenotrophomonas maltophilia (34.0 %), Pseudomonas aeruginosa (27.8 %), and Streptococcus agalactiae (27.8 %) were the top three prevalent respiratory pathogens detected in plaque samples. There was a significantly higher prevalence of respiratory pathogens residing on unclean than clean prostheses (P = 0.046). However, the ORPIs in both groups showed no statistically significant difference (P = 0.516).

CONCLUSIONS

The ORPIs for both clean and unclean prostheses demonstrated a similar abundance of respiratory pathogens. However, the high prevalence of respiratory pathogens residing on unclean prostheses should not be underestimated. Therefore, maintaining good prosthesis hygiene is still important for overall oral and systemic health, even though the direct link between prosthesis cleanliness and reduced abundance of respiratory pathogens has not been established.

CLINICAL SIGNIFICANCE

The association between the prevalence of respiratory pathogens and unclean removable prostheses has been demonstrated and might increase the theoretical risk of respiratory disease development.

Characterization of pathogenic microbiome on removable prostheses with different levels of cleanliness using 2bRAD-M metagenomic sequencing

Background

The microbiomes on the surface of unclean removable prostheses are complex and yet largely underexplored using metagenomic sequencing technology.

Objectives

To characterize the microbiome of removable prostheses with different levels of cleanliness using Type IIB Restriction-site Associated DNA for Microbiome (2bRAD-M) sequencing and compare the Microbial Index of Pathogenic Bacteria (MIP) between clean and unclean prostheses.

Materials and Methods

Ninety-seven removable prostheses were classified into 'clean' and 'unclean' groups. All prosthesis plaque samples underwent 2bRAD metagenomic sequencing to characterize the species-resolved microbial composition. MIPs for clean and unclean prostheses were calculated based on the sum of the relative abundance of pathogenic bacteria in a microbiome using a reference database that contains opportunistic pathogenic bacteria and disease-associated information.

Results

Beta diversity analyses based on Jaccard qualitative and Bray-Curtis quantitative distance matrices identified significant differences between the two groups (p < 0.05). There was a significant enrichment of many pathogenic bacteria in the unclean prosthesis group. The MIP for unclean prostheses (0.47 ± 0.25) was significantly higher than for clean prostheses (0.37 ± 0.29), p = 0.029.

Conclusions

The microbial community of plaque samples from 'unclean' prostheses demonstrated compositional differences compared with 'clean' prostheses. In addition, the pathogenic microbiome in the 'unclean' versus 'clean' group differed.

Evaluation of dental students' clinical communication skills from three perspective approaches: A cross-sectional study

INTRODUCTION

The communication skills of clinicians are very crucial in providing better health outcomes for patients. Therefore, this study aimed to assess undergraduate dental students' communication skills in relation to their demographics and clinical setting using a three-perspective approach; the student, the patient and the clinical instructor perspective.

METHODS

A cross-sectional study was conducted using validated modified-communication tools; Patient Communication Assessment Instruments (PCAI), Student Communication Assessment Instruments (SCAI) and Clinical Communication Assessment Instruments (CCAI) which included four communication domains. One hundred and seventy-six undergraduate clinical year students were recruited in this study whereby each of them was assessed by a clinical instructor and a randomly selected patient in two settings: Dental Health Education (DHE) and Comprehensive Care (CC) clinic.

RESULTS

Comparing the three perspectives, PCAI yielded the highest scores across all domains, followed by SCAI and CCAI (p < .001). SCAI exhibited a better score in Year 5 compared to Year 3 and Year 4 (p = .027). The male students perceived they performed better than females in all domains (p < .05). Patients rated the students higher in the DHE clinic as compared to the CC clinic for the team interaction domain.

CONCLUSION

There was an upward pattern of the communication skills score rated from the clinical instructor perspective to the student and patient perspectives. The use of PCAI, SCAI and CCAI collectively gave a complementary view of students' communication performance in all the domains assessed.

Porous NiTi Dental Implant Fabricated by a Metal Injection Molding: An in Vivo Biocompatibility Evaluation in an Animal Model

This study assessed the corrosion resistance, intracutaneous reactivity, acute systemic toxicity, and in situ tissue effect of the implantation of porous NiTi fabricated by metal injection molding in animal models. For the intracutaneous reactivity study, five intracutaneous injections were administered per site with and without the tested extract in polar and nonpolar solutions. The extract was also delivered via intravenous and intraperitoneal routes for acute systemic toxicity. TiAl6 V4 (control) and porous NiTi were implanted in rabbit femora for a period of 13 weeks to evaluate the in situ tissue response. Corrosion was evaluated through open and cyclic polarization in PBS, while biocompatibility was investigated by assessing the general conditions, skin irritation score (edema and erythema), and histopathology. No active dissolution or hysteresis loop was observed in the corrosion study. None of the animals exhibited death, moribundity, impending death, severe pain, self-mutilation, or overgrooming. No edema was observed at injection sites. Only the positive control showed an erythematous reaction at 24, 48, and 72 h observations (p < 0.001). Porous NiTi showed a low in situ biological response for inflammation, neovascularization, and fibrosis in comparison to the control implant (p = 0.247, 0.005, and 0.011, respectively). Porous NiTi also demonstrated high pitting corrosion resistance while causing no acute hypersensitivity or acute systemic toxicity. The study concludes that porous NiTi implants were unlikely to cause local sensitization, acute systemic toxicity, or chronic inflammatory reactions in an animal model. Porous NiTi also exhibited osseointegration equivalent to Ti6AI4 V of known biocompatibility.

Patient satisfaction following resin-bonded fixed dental prostheses cemented by using the Dahl concept

OBJECTIVE

Resin-bonded fixed dental prostheses (RBFDPs) cemented at an increased occlusal vertical dimension (OVD) (the Dahl concept) to create space for a metal retainer remains controversial because of the lack of reported clinical studies. This study analyzed the demographic (age and sex) and clinical factors (location and arch of prosthesis) affecting the patients' perception of RBFDPs cemented at an increased OVD.

MATERIAL AND METHODS

Twenty-eight participants treated with cantilevered RBFDP at an increased OVD were prospectively recruited. They were asked to answer a validated patient satisfaction questionnaire based on six parameters during the 12-week review visit.

RESULTS

71.4% of the participants were completely satisfied with the color, shape, and function. Twenty-one (75%) participants reported no complaints about the prostheses. 89.3% will recommend this treatment option to others. There was a significant difference between males and females in avoiding loading on the prostheses (p = 0.015). The level of satisfaction did not differ by age, ethnicity, location, and arch of the prostheses (p > 0.05).

CONCLUSIONS

Patient satisfaction toward RBFDP cemented by using the Dahl approach was generally high on all the parameters at the 12-week review visit.

SURVIVAL AND COMPLICATION RATES OF RESIN COMPOSITE LAMINATE VENEERS: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVES

The aim of this systematic review was to evaluate the survival and complication rates of resin composite laminate veneers.

METHODS

Randomized controlled trials and cohort studies with a minimum 2-year follow-up assessing survival and complication rates of resin composite laminate veneers on permanent dentition from 1998 to May 2022. Literature searches were conducted in MEDLINE (PubMed), Scopus, and the Cochrane Central Register of Controlled Trials electronic databases. References cited in the related reviews and included full-text articles were also hand-searched to further identify potentially relevant studies.

RESULTS

A total of 827 articles were identified. Twenty-two studies were considered for full-text review after the title and abstract screening stage. After exclusion, 7 studies (3 randomized controlled trials and 4 cohort studies) were included in the systematic review. Three published scales were adopted for the quality and risk of bias assessment. At the survival rate threshold, the overall heterogeneity (I2) for randomized controlled trials was 50.5% (P = .108). The overall pooled survival rate of the randomized controlled trials was 88% (95% CI: 81%-94%), with the mean follow-up time ranging from 24 to 97 months. Surface roughness, color mismatch, and marginal discoloration were the most reported complications.

CONCLUSION

Resin composite laminate veneers demonstrated moderately high survival rates for the entire sample and the direct laminate veneer group demonstrated higher survival rates than the indirect approach. Most of the complications were regarded as clinically acceptable with or without reintervention.

Prevalence of respiratory pathogens colonizing on removable dental prostheses in healthy older adults: A systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to investigate the prevalence of opportunistic respiratory pathogens colonizing removable dental prostheses in older adults without respiratory diseases.

METHODS

This review was registered with PROSPERO and conducted in accordance with the principles formed by the working group of the Joanna Briggs Institute (JBI) to evaluate systematic reviews of prevalence data. Literature searches were conducted across five electronic databases. Quality assessments were determined according to a revised JBI critical appraisal checklist across nine criteria. Comparison between fixed- and random-effects meta-analyses were performed for sensitivity analysis. Prediction intervals were also presented when three or more studies were included in the meta-analysis.

RESULTS

Across the databases, 1091 articles were identified, and 591 articles remained after the removal of duplications. Twenty 'potentially effective' studies were identified. Ultimately eight studies informed this review and meta-analyses were performed for 13 known respiratory pathogens. The meta-analyses identified the top three common respiratory pathogens residing on the removable prostheses were, in descending order: Staphylococcus aureus: 31.81% (95% CI: 13.34% to 48.24%); Staphylococcus epidermidis: 14.07% (95% CI: 7.88% to 21.48%); Klebsiella pneumoniae: 10.50% (95% CI: 2.55% to 22.30%). The heterogeneity scores for nine respiratory pathogen analyses were classified as 'unimportant inconsistency', I2 = 0% (P > 0.1). For sensitivity analysis, there was no difference between the random- and fixed-effects models.

CONCLUSION

The existing evidence demonstrated a high burden of certain opportunistic respiratory pathogens, which may be considered a major potential cause of respiratory infections in older adults wearing removable prostheses. This article is protected by copyright. All rights reserved.

Agreement in quantification of removable prosthesis plaque area coverage using a semi-automated planimetric assessment method

OBJECTIVES

To determine the agreement of removable dental prosthesis cleanliness as assessed by a semi-automated planimetric method between images captured by a digital single-lens reflex camera (DSLR) and smartphone.

METHODS

A total of 97 participants with removable prostheses were recruited for the quantification of the prosthesis plaque area coverage. The colour images of stained prosthesis plaque were obtained using both a DSLR camera and a smartphone. The prosthesis plaque area coverage was analysed in two ways: (i) prosthesis cleanliness index (PCI) and (ii) percentage plaque area coverage (PPC). The PPC (continuous data) was converted to the PCI (categorical data) to provide prevalence ordinal scales and the agreements in PCI ratings were determined using weighted Kappa statistics. Agreement of PPC scores was determined through assessing directional, standardised directional, and absolute differences and correlation analyses.

RESULTS

Weighted Kappa values of agreement between PCI categories were excellent (> 0.80) for all comparisons. The mean PPC was 24.79 % as determined by DSLR and 25.37 % as determined by smartphone. There was no statistically significant difference in the means of PPC between the DSLR and smartphone (P = 0.149). The standardised directional difference was 0.15 ('small'). The mean absolute difference was 2.77. The interclass correlation coefficient was 0.98 ('excellent').

CONCLUSIONS

This method showed almost perfect agreements and allowed for threshold-based plaque segmentation on the removable prostheses. There was substantial agreement between DSLR and smartphone assessment of prosthesis plaque area coverage as determined by a semi-automated planimetric assessment.

CLINICAL SIGNIFICANCE

This semi-automated planimetric assessment method has implications for monitoring removable prosthesis hygiene initiatives by offering a valid, reliable, and quantitative method of assessment with potential use in managed care and community settings.

Structural Integrity of Anterior Ceramic Resin-Bonded Fixed Partial Denture: A Finite Element Analysis Study

This study was conducted as a means to evaluate the stress distribution patterns of anterior ceramic resin-bonded fixed partial dentures derived from different materials and numerous connector designs that had various loading conditions imposed onto them through the utilization of the finite element method. A finite element model was established on the basis of the cone beam computed tomography image of a cantilevered resin-bonded fixed partial denture with a central incisor as an abutment and a lateral incisor as a pontic. Sixteen finite element models representing different conditions were simulated with lithium disilicate and zirconia. Connector height, width, and shape were set as the geometric parameters. Static loads of 100 N, 150 N, and 200 N were applied at 45 degrees to the pontic. The maximum equivalent stress values obtained for all finite element models were compared with the ultimate strengths of their materials. Higher load exhibited greater maximum equivalent stress in both materials, regardless of the connector width and shape. Loadings of 200 N and 150 N that were correspondingly simulated on lithium disilicate prostheses of all shapes and dimensions resulted in connector fractures. On the contrary, loadings of 200 N, 150 N, and 100 N with rectangular-shaped connectors correspondingly simulated on zirconia were able to withstand the loads. However, two of the trapezoidal-shaped zirconia connectors were unable to withstand the loads and resulted in fractures. It can be deduced that material type, shape, and connector dimensions concurrently influenced the integrity of the bridge.

The Perspective of Dental Aesthetics in Finding a Job as a Dentist: A Cross-Sectional Study

This study aimed to determine the influence of dental aesthetics in finding a job as a dentist and the employer’s willingness to interact in personal and professional setting. Ten dental students’ smiling photographs were taken prior to the correction of their dental aesthetic problems. The images were digitally altered to an ideal smile. Two different questionnaires were prepared (Groups A and B) with the images with or without alteration (ideal and non-ideal smile). The images with an ideal smile and non-ideal smile were randomly allocated in each group and assessed by 84 private dental practitioners who has the authority of hiring another dentist in their practice. Four questions were asked on the likelihood of being hired, friendliness, intelligence, and good clinical skills. In general, the students with ideal smile were more likely to be hired (p < 0.05) except for those presented with buccally erupted canine and mild median diastema. Students with ideal smile scored higher in terms of friendliness and intelligence than the non-ideal smile. Most of them did not correlate a smile to an individual’s clinical skills and manual dexterity (p > 0.05). In conclusion, individuals with an ideal smile was graded more friendly and intelligent thus increases the employer’s willingness to interact personally and is more likely to be hired in contrast to a person with a non-ideal smile. Therefore, an aesthetically pleasing smile is one of the factors affecting the chances of a dentist to be hired and improve their personal interaction with people.

Creating space for a resin-bonded fixed partial denture retainer by using the Dahl concept

A technique is presented for creating interocclusal space for a resin-bonded fixed partial denture retainer by applying the Dahl concept. A missing mandibular first molar was replaced with a cantilevered resin-bonded fixed partial denture and had been successfully retained at the 9-year clinical review.

Comparison between conventional teaching and blended learning in preclinical fixed prosthodontic training: A cross-sectional study

INTRODUCTION

Blended learning utilizes technology with reduced face-to-face time and promotes a student-centred learning environment that excites the learning process. However, studies on blended learning in fixed prosthodontics is still lacking. This study aimed to compare students' performance in easy and difficult level of fixed prosthodontic preclinical projects given by either blended learning or conventional teaching.

METHODS

A cross-sectional study was conducted on 72 s-year dental students, who attended preclinical fixed prosthodontic training. Participants were randomly segregated into conventional teaching (n = 36) and blended learning (n = 36). All participants were evaluated for learning preferences using Visual-Aural-Read/Write-Kinesthetic (VARK) questionnaire and performed a project as their baseline skill assessment. They performed another two preclinical projects (easy and difficult level) after the allocated teaching approach. Learning preferences were analysed using Fisher's exact test and performance in preclinical projects were analysed with an independent t test (significant at p < .05).

RESULTS

The highest prevalence of learning preferences was the quad-modal preferences (50.7%), which were visual, auditory, reading/writing and kinesthetic. There were no significant differences in baseline skills and learning preferences (p > .05) between groups. No significant differences found between both teaching approaches for easy (p = .319) and difficult projects (p = .339). In the blended learning group, no significant difference was found in both difficulty level of projects (p = .064).

CONCLUSION

The participants performed equally on both teaching approaches. However, blended learning for preclinical fixed prosthodontics is anticipated as the new norm of learning, especially in the current pandemic with reduced face-to-face time.

Laypersons’ Perception Towards Gummy Smile and Facial Types: Acceptability and Treatment Benefit

Smile aesthetic perceptions could have different impact on orthodontic and prosthodontic treatment management and options to the patient. Objectives: To determine the laypersons’ smile aesthetic perceptions; irrespective of age and gender, of gummy smile and its treatment need and benefit on three different facial types. Methods: Smiling frontal photographs of a male and female subject were altered to simulate three facial types (brachyfacial, mesofacial and dolichofacial) with different levels of gummy smile increase from 2.0mm to 5.0mm. A total of 150 laypersons ranging from 18-45 years old were randomly approached to rate the photographs. Perceptions differences were assessed using visual analog scale for each group. Results: Repeated measure ANOVA was applied and showed that the mean level of attractiveness among three different facial types based on gummy smile levels was not statistically significant. This suggests that the facial type does not influence the laypersons’ ratings on gummy smile level. Further test found that the laypersons perceived 4.0mm gummy smile as borderline attractive while at 5.0mm is considered as unaesthetic. Chi Square test showed that there was statistically significant difference between the treatment need and attractiveness scoring (p=<0.01) whereby the treatment benefit is dependent on attractiveness ratings of gummy smile variables. Conclusion: Different levels of gingival show affect the laypersons’ perception of smile attractiveness, regardless of the facial type. The higher the level of gingival show, as seen in 4-5mm categories is perceived to be unattractive and thus, more likely to benefit from treatment.

Development and validation of a progressive web application to educate partial denture wearers

Effective delivery of post-insertion instructions is essential for denture care and oral health. This study aimed to develop a progressive web application (PWA) to educate patients' chairside and serve as a reference material. A need analysis was conducted before prototype development. Subsequently, the prototype was subjected to content verification, design appraisal and usability testing. The results of usability testing revealed a user task success rate of 94.4%, with an adjusted Wald 95% confidence interval of 83-100%. User satisfaction assessed using the Single Ease Questionnaire and System Usability Score reported a mean score of 6.13 (95% CI: 5.69-6.55) and 85.9 (95% CI: 82.2-89.6), respectively, indicating good usability. This study highlights the systematic approach of developing an evidence-based educational PWA to meet the usability standards for mobile applications. This PWA is useful in clinical studies to explore mobile technologies' potential in educating denture wearers, especially in the older population.

Management of Localized Anterior Tooth Wear Using a Modified Sandwich Technique and the Dahl Concept: A Case Report

This case report illustrates a minimally invasive segmental rehabilitation of localized anterior tooth wear using a modification of the sandwich technique, a combination of indirect palatal composite veneers and direct labial composite restorations, at an increased occlusal vertical dimension (the Dahl concept).

The Relationship of Facial Measurements with the Mesiodistal Width of the Maxillary Anterior TeethWidth of the Maxillary Anterior Teeth

The relationship between facial measurements and the size of the maxillary anterior teeth in the Malaysian population is still a point of contention. Objective: The purpose of this study was to establish a relationship between facial measurements and the mesiodistal width of the maxillary anterior teeth (MDW), which could be used to guide the selection of anterior teeth for complete denture construction. Methods: The facial and dental measurements were obtained directly from 170 Malay adults aged between 19 to 35 who had morphologically normal permanent maxillary anterior teeth from canine to canine. The facial dimensions measured were interpupillary distance (IPD), intercanthal distance (ICD) and interalar distance (IAD). The facial dimensions were measured using a digital vernier calliper while the mesiodistal width of the maxillary anterior teeth was measured with a flexible ruler. The three facial dimensions were correlated with MDW for both genders. Results: The IPD and IAD were significantly (p>0.001) larger in males (IPD: 68.30±4.24mm; IAD: 39.60±2.54mm) than in females (IPD: 65.93±3.91mm; IAD: 36.96±2.29). There was no significant correlation between any of the facial dimensions and MDW in males or females. Conclusion: For the studied population, the interpupillary, intercanthal, and interalar distances may not be used as reliable guides when determining the size of maxillary anterior teeth in complete denture construction

Effect of educational progressive web application on patient's oral and denture knowledge and hygiene: A randomised controlled trial

This study aimed to evaluate the effect of a novel progressive web application (PWA) on the patient's oral and denture knowledge and hygiene. Fifty-two removable partial denture wearers were randomised to receive education using the PWA, or verbal instructions accompanied by demonstration of hygienic procedures. Changes in the participants' knowledge score, plaque index, gingival index and denture plaque was evaluated during a follow-up period of 3 months. The participants' acceptance of PWA was explored through usage logs and a feedback form. Both groups showed significant improvement in knowledge scores, oral and denture hygiene indices (p < 0.001) after education. The PWA group demonstrated significantly lower gingival index score than control (p = 0.008) at the third month review. In conclusion, there is potential of using mobile application in educating elderly patients and the PWA is a viable option for providing post-denture delivery instructions.

An unusual endodontic complication following crown lengthening surgery: A Case Report

A gummy smile is a form of excessive gingival display when smiling. The excessive gingival display due to altered eruption is likely to benefit from crown lengthening surgery in order to restore the esthetic smile. Case Report: The potential complications of the crown lengthening surgery include possible esthetic deformities, dentine hypersensitivity, transient mobility, and root resorption. The present case report reveals a rare complication happened after an esthetic crown lengthening surgery which was performed to correct the gummy smile of a 37-year-old female. The patient experienced dull throbbing pain and mild tender to percussion on tooth 11, 3 weeks after the surgery, and the symptoms did not improve after the composite restorations were placed at the cervical regions. Instead, the tooth was tender to percussion and palpation with a sign of coronal discoloration. Pulp necrosis was confirmed with the clinical tests. A cone-beam computed tomography was taken after the root canal treatment, and apical fenestration on tooth 11 was noted. Therefore, this case report shows the possible correlation between crown lengthening surgery on a tooth with apical fenestration and pulp necrosis, if the apical vasculature is severed accidentally during the procedure. Conclusion: A cone-beam computed tomography should be considered prior to the surgery and extra precaution during the surgery may reduce the risk of severing the apical vasculature if apical fenestration is evidenced.

Occlusal force and occlusal contact reestablishment with resin-bonded fixed partial dental prostheses using the Dahl concept: A clinical study

STATEMENT OF PROBLEM

Space creation for a metal retainer of the resin-bonded fixed partial dental prostheses (RBFPDPs) with the Dahl concept remains controversial because of the lack of clinical studies.

PURPOSE

The purpose of this clinical study was to investigate the occlusal force and occlusal contact reestablishment of RBFPDPs cemented at an increased occlusal vertical dimension (the Dahl concept) and to evaluate the factors affecting them.

MATERIAL AND METHODS

A prospective clinical study was carried out on 28 participants receiving cantilevered RBFPDPs at an increased occlusal vertical dimension at the Faculty of Dentistry, University Teknologi MARA. Maximum occlusal forces were recorded at precementation, postcementation, and 12-week review visit by using pressure indicating film, while occlusal contact reestablishment was assessed at the precementation stage and 12-week review visit by using shim stock foils. The Wilcoxon signed-rank and chi-squared tests were used for statistical analysis (α=.05).

RESULTS

Significant differences were found for maximum occlusal force between the precementation and the postcementation and between the postcementation and the 12-week review of RBFPDPs (P<.05 for both) in all 28 participants. However, no significant difference was found between the precementation and the 12-week review (P=.085). The occlusal force reestablishment concerning sex, age, location, and arch of the prosthesis was found to be similar. Most of the participants (89.3%) achieved complete occlusal contact reestablishment and 10.7% partial occlusal reestablishment. The demographic and prosthesis factors were not significantly related to the occlusal reestablishment (P>.05).

CONCLUSIONS

Overall, occlusal force was reestablished after 12 weeks, and occlusal contact was completely reestablished in most participants after placement of RBFPDPs at an increased occlusal vertical dimension.

Occlusal re-establishment and clinical complications of resin-bonded fixed partial dental prostheses cemented at an increased occlusal vertical dimension: A retrospective study

STATEMENT OF PROBLEM

Resin-bonded fixed partial dental prostheses (RBFPDPs) cemented at an increased occlusal vertical dimension (OVD) (the Dahl concept) to create space for a metal retainer remain controversial because of the lack of reported clinical studies. This study evaluated RBFPDPs by applying the Dahl concept.

PURPOSE

The purpose of this retrospective study was to investigate the clinical factors affecting the occlusal re-establishment and short-term complications of RBFPDPs cemented at an increased OVD.

MATERIAL AND METHODS

Occlusal re-establishment and clinical complications were reviewed in 109 participants (155 RBFPDPs) treated at the Faculty of Dentistry, Universiti Teknologi MARA from January 2013 to May 2018. Types of complications and risk factors were assessed from clinical data. Demographic factors, clinical factors, and prosthesis factors were distinguished and their association with occlusal re-establishment analyzed by using multiple regression analysis.

RESULTS

A total of 155 RBFPDPs (42 anterior, 113 posterior) were placed in 109 participants. All achieved occlusal re-establishment, 89.9% complete occlusal re-establishment and 10.1% partial occlusal re-establishment, a minimum of 4 months after the RBFPDPs had been placed at an increased OVD. The design of the metal retainer coverage was found to be a significant factor affecting occlusal re-establishment and decementation (P<.05). Widening of the periodontal ligament space was the most common complication (29.2%).

CONCLUSIONS

RBFPDPs cemented at an increased OVD can be clinically recommended. The design of the retainer coverage was a significant factor influencing occlusal re-establishment and clinical complications.

The effect of remote ischaemic preconditioning on myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery

In several recent clinical trials on cardiac surgery patients, remote ischaemic preconditioning (RIPC) showed a powerful myocardial protective effect. However the effect of RIPC has not been studied in patients undergoing off-pump coronary artery bypass graft surgery. We evaluated whether RIPC could induce myocardial protection in off-pump coronary artery bypass graft surgery patients. Patients undergoing elective off-pump coronary artery bypass graft surgery were randomly allocated to the RIPC (n = 65) or control group (n = 65). After induction of anaesthesia, RIPC was induced by four cycles of five-minute ischaemia and reperfusion on the upper limb using a pneumatic cuff. Anaesthesia was maintained with sevoflurane, remifentanil and vecuronium. Myocardial injury was assessed by troponin I before surgery and 1, 6, 12, 24, 48 and 72 hours after surgery. There were no statistical differences in troponin I levels between RIPC and control groups (P = 0.172). Although RIPC reduced the total amount of troponin I (area under the curve of troponin increase) by 26%, it did not reach statistical significance (RIPC group 53.2 +/- 72.9 hours x ng/ml vs control group 67.4 +/- 97.7 hours x ng/ml, P = 0.281). In this study, RIPC by upper limb ischaemia reduced the postoperative myocardial enzyme elevation in off-pump coronary artery bypass graft surgery patients, but this did not reach statistical significance. Further study with a larger number of patients may be needed to fully evaluate the clinical effect of RIPC in off-pump coronary artery bypass graft surgery patients.

Light activated disinfection: an alternative endodontic disinfection strategy

BACKGROUND

An improved light activated disinfection technique utilizing a specific photosensitizer formulation, liquid optical-conduit, oxygen-carrier and light energy of appropriate wavelength has been introduced recently. This study tested the efficacy of this improved light activated disinfection on ex vivo biofilms of Enterococcus faecalis at two different stages of maturation.

METHODS

Eighty-five tooth sections were prepared and endodontic biofilm of E. faecalis were grown within the root canal. In stage 1, conventional light activated disinfection (LAD), chemical disinfectant (sodium hypochlorite) and improved LAD were tested on four-day-old (immature) biofilms. In stage 2, conventional LAD, improved LAD and chemomechanical disinfection (alone and in combination with improved LAD) were tested on four-week-old (mature) biofilms.

RESULTS

Sodium hypochlorite and improved LAD showed the ability to significantly inactivate bacteria in four-day-old biofilms when compared to the control and LAD (p < 0.05). Inactivation of bacteria from deeper dentine was higher in improved LAD than sodium hypochlorite. In four-week-old biofilms, a combination of chemomechanical disinfection and improved LAD produced significant bacterial killing compared to either chemomechanical disinfection or improved LAD alone.

CONCLUSIONS

This study highlighted the potential of improved LAD to kill bacteria within dentinal tubules. In combination with chemomechanical preparation, the improved LAD significantly inactivated four-week-old biofilm bacteria.

Transmission of tuberculosis from patient to healthcare workers in the anaesthesia context

INTRODUCTION

Pulmonary tuberculosis (PTB) is prevalent in our population. We report an incident of healthcare workers (HCWs) suspected of being infected by a patient with undiagnosed active PTB in the operating theatre.

CLINICAL PICTURE

A 60-year-old patient admitted for intestinal obstruction, underwent an emergency laparotomy. Preoperative chest X-ray (CXR) showed diffuse reticular-nodular shadowing and postoperative sputum was positive for acid-fast bacilli.

TREATMENT

The patient was isolated and treated for active tuberculosis. The anaesthetist and her assistants in the operating theatre that day were referred to the infectious disease physician and some were started on tuberculosis prophylaxis.

OUTCOME

The patient and the HCWs involved recovered.

CONCLUSION

Thus, all PTB-susceptible patients with suggestive CXR should be treated as potentially infective. Adequate personnel protection should include highly efficient facemasks and shields. Risk of patient-to-patient transmission of tuberculosis through the anaesthetic circuit is low if effective bacterial/viral filters are used.

Classic Kaposi sarcoma presenting as rapidly growing nodules

Classic Kaposi sarcoma (KS) is a sporadic disease that usually affects persons older than 50 years, with a distinct male predominance. Although classic KS has a protracted, indolent course, there appears to be a rare disseminated fulminant type. This report describes a case of classic KS, presenting as a very rapid enlargement and dissemination of skin lesions, without evidence of human immunodeficiency virus (HIV) infection or involvement of other internal organs.

Pedunculated atypical cellular blue nevus

Atypical variants of cellular blue nevus are considered to have features intermediate between typical cellular blue nevus and rare malignant blue nevus; they usually show bizarre pleomorphic cells which have prominent nucleoli. We describe a 37-year-old-Korean woman who had had an asymptomatic pedunculated single mass on her right thigh for 17 years. A skin biopsy showed a tumor consisting of intensely pigmented dendritic cells and less or nonpigmented epitheloid cells in the dermis with striking atypia. There has been no evidence of recurrence for 3 years after surgery. The diagnosis of atypical cellular blue nevus was made on the basis of clinical features and skin biopsy findings.

Vasopressin effective in reversing catecholamine-resistant vasodilatory shock

A patient with perforated appendicitis developed progressive vasodilatory shock which was complicated by perioperative acute myocardial infarction. Cardiovascular support included dopamine infusion, and later, intra-aortic balloon counterpulsation balloon pump and noradrenaline and dobutamine infusion. Vasopressin was introduced as a final attempt to reverse the refractory shock and was associated with recovery. The experience with this case suggests that vasopressin may be a valuable adjunct to the treatment of catecholamine-resistant vasodilatory shock.

A case of pachyonychia congenita with oral leukoplakia and steatocystoma multiplex

Pachyonchia congenita (PC) is an uncommon autosomal dominant genodermatosis affecting the nails and other ectodermal tissues. The most striking features are symmetrically thickened dysmorphic nails and hyperkeratotic skin lesions. We report a case of pachyonychia congenita in a 30-year-old male patient who had thickening and gray-brown discoloration of all nails and many nodules on his back and neck. He also had hyperkeratotic skin lesions on both feet. His tongue had irregularly-shaped, whitish plaques. Histology of these nodules revealed the characteristic features of steatocystoma multiplex. After treatment with oral retinoic acid, his hyperkeratotic skin lesions improved.

Premedication with midazolam is more effective by the sublingual than oral route

PURPOSE

This study compared the sedative effects of sublingual tablet midazolam (Roche Dormicum 7.5 mg) with the oral route as premedication.

METHODS

One hundred ASA physical status I and II gynaecological patients were randomly selected to receive a 7.5 mg tablet of midazolam either sublingually or orally as premedication about one hour before elective surgery. There were 50 patients in each group. The degree of sedation was assessed according to the Ramsay scale initially and then at 20, 30, 45 and 60 min intervals by a second observer blinded to the route of administration. The time for complete drug dissolution was studied in the sublingual group by the inspection of tablet residue under the tongue every five minutes for 20 min, then the patients were interviewed regarding their acceptance of taste.

RESULTS

The sedation scores in the sublingual group were higher than in the oral group at 30 and 60 min after drug administration. (P = 0.0054 and P = 0.008) Seventy-two percent of the sublingual group had complete drug dissolution within 10 min and 64% of the patients in the sublingual group found the tablet acceptable with regard to its taste.

CONCLUSION

Midazolam 7.5 mg sublingual is a more effective pre-anaesthetic sedative than by the oral route.

The effect of diethylcarbamazine citrate on incidence and recovery rates of Brugia malayi microfilaremia in Sabah, Malaysia

Mass drug administration via 3 modes of delivery reduced the incidence and prevalence rates and intensity of Brugia malayi infection in 3 rural villages in the Bengkoka Peninsula, Sabah, in 1982-1983. A dosage of 6 mg diethylcarbamazine citrate (DEC-C)/kg body weight was administered either daily or weekly (total of 6 doses, 36 mg/kg body weight), and impact on B. malayi cases were comparable in the 3 villages. A total of 384 people participated in the DEC-C regimens, and all pregnant women and children under 2 years were excluded from the study. Bekessy's method of estimation of incidence and recovery rates was applied to data on B. malayi microfilaremia before drug administration. Treatment with DEC-C by any of the 3 modes of delivery drastically reduced the number of episodes of patent microfilaremia, incidence and prevalence, and median microfilarial density. Reduction was sustained for at least 18 to 24 months after treatment.

Analysis of heavy metal immunotoxicity by multiparameter flow cytometry: correlation of flow cytometry and immune function data in B6CF1 mice

Bone marrow and spleen cells obtained from female B6C3F1 mice given a single i.p. exposure to cadmium acetate (0.9 mg/kg), lead acetate (12 mg/kg), or sodium acetate (12 mg/kg), were studied using flow cytometry, immunologic, and hematologic assays. Significant changes were detected in subpopulations of bone marrow cells using multiparameter flow cytometry within 1 day following treatment with cadmium or lead. Bone marrow cells obtained from B6C3F1 mice 5 days after treatment with cadmium or lead were found to have a decreased number of cells expressing Mac-1, 55-7.2, 14.8, and Lyt-1 antigens, suggesting a shift to immature cell types. An increase in the number of progenitor cells (CFU-C) obtained from the bone marrow of mice treated with heavy metals was also noted 5 days after exposure to cadmium or lead. A time-dependent suppression of the in vitro primary humoral immune response of spleen cells to SRBCs, TNP-Ficoll and TNP-LPS was produced by cadmium or lead treatment. Suppression of the mitogenic response of spleen cells to Con A, PHA, and LPS was also found to be time-dependent. Spleen cell surface marker expression (Mac-1, Lyt-1, Lyt-2 and 14.8) was altered in response to cadmium or lead treatments, but these changes did not appear to correlate with the humoral immunity or mitogen-induced proliferation data. These studies demonstrate that changes in cell surface markers on discrete subpopulations of lymphoid cells present in the spleens of heavy metal exposed mice may not correlate with alterations in the functional activity of these cells. However, changes in murine bone marrow surface markers in response to cadmium or lead treatment predicts a shift to immature cell types, which appeared to correlate with the increase in CFU-C activity.

Flow cytometry Coulter volume analysis of lead- and cadmium-induced cellular alterations in bone marrow obtained from young adult and aged Balb/c mice

Flow cytometry Coulter volume analysis was used to examine the effects of an acute exposure to cadmium or lead on subpopulations of Balb/c bone marrow cells. A significant shift in the volume of Balb/c bone marrow cells was detected in response to a single i.p. injection of cadmium acetate (Cd) or lead acetate (Pb) compared to sodium acetate (Na)-treated mice. An increase in the relative number or size of myeloid/monocytic cells was noted in the bone marrow of cadmium or lead-treated mice. This effect was more pronounced in aged Balb/c mice than in young adults. These studies suggest the flow cytometry Coulter volume analysis may be a useful and sensitive technique for the assessment of cellular changes that occur in the bone marrow in response to xenobiotic exposure.

Hemadsorption immunosorbent technique for the detection of dengue immunoglobulin M antibody

We developed a highly specific, sensitive, and economical hemadsorption immunosorbent technique for the detection of dengue-specific immunoglobulin M (IgM) antibody. The technique is based on the reaction of human sera with anti-human IgM immobilized onto a solid phase followed by the detection of dengue-specific IgM by the addition of a known quantity of dengue virus hemagglutinin and goose erythrocytes. Dengue-specific IgM-positive sera showed hemadsorption. IgM antibody specific for dengue virus was detected in 22 of 39 (56%) convalescent-phase sera from primary dengue infections and 8 of 10 (80%) convalescent-phase sera from secondary dengue infections. Additionally, 32 of 76 single sera from patients were positive for dengue IgM; these sera were previously uninterpretable by the hemagglutination inhibition test, as only a single serum specimen was available. No false-positive results were obtained with sera that were negative by the hemagglutination inhibition test for dengue virus. Crude dengue virus hemagglutinin preparations could be used without purification. Dengue-specific IgG did not interfere with the results, nor was there any cross-reactivity between dengue hemagglutinins and IgM specific for other viruses. Some cross-reactivity of the dengue-specific IgM was observed with Japanese encephalitis virus hemagglutinins, but this did not present any problems in the interpretation of results. This test is specific, inexpensive, highly reproducible, and simple to perform.

Rainfall, abundance of Aedes aegypti and dengue infection in Selangor, Malaysia

An epidemio-meteorotropic analytical study of Selangor, in the Southwest coast of Peninsular Malaysia, examines the monthly incidence of dengue for the period 1973-1982 to assess possible quantitative association with the monthly rainfall. The relationships between rainfall, abundance of A. aegypti and dengue infection during 1982 in Jinjang, a dengue-prone area in Selangor, were also examined. A quantitative association between rainfall and the number of dengue cases was found during the first wet period. The lag time between the onset of heavy rain and dengue outbreak was about two to three months. A 120% increase in the number of dengue cases was observed when the monthly rainfall was 300 mm or more. Positive associations were seen between the incidence of dengue and the Aedes house index and the Breteau index in Jinjang. The relationships between these three variables and rainfall suggest that the latter might have exerted its effect on dengue infection partly through the creation of more breeding sites for A. aegypti. Assessment of the importance of A. aegypti in the transmission of dengue in this locality was not possible because of the lack of adjustment for A. albopictus, the other known vector of dengue in the state, and for social and other environmental factors influencing infection rates. In spite of this and the interpretational problems common in aggregate studies, the present analyses have provided relatively strong statistical evidence of an association between rainfall and dengue outbreaks in Selangor, thereby indicating that it is a factor worthy of careful surveillance and monitoring.

The 1982 dengue epidemic in Malaysia: epidemiological, serological and virological aspects

In 1982, Malaysia experienced the worst dengue/dengue haemorrhagic fever outbreak in its history. All states in Peninsular and East Malaysia were similarly affected. There was a total of 3,005 cases with 35 deaths, with the majority of cases occurring between the months of July to October. There was a total of 1,001 laboratory confirmed cases. Most of the cases were in patients over the age of 15 years. The Chinese population was mainly affected, although a much higher proportion of Malays was noted in comparison to previous years. The main serotypes involved were dengue-1 and dengue-3. No dengue-4 serotype were isolated.

A double antibody sandwich micro-ELISA kit for the rapid diagnosis of snake bite

A micro ELISA assay was established to diagnose systemic poisoning for the rapid administration of specific antivenom. Rabbit anti venom IgG was bound to the solid phase to enable detection of venom from both the Malayan Pit Viper (Agkistrodon rhodostoma) and the Common Cobra (Naja naja). This assay is read visually and takes 35 to 45 minutes to perform. It can detect 15.6 ng/ml of viper venom in 75 minutes and 7.8 ng/ml of cobra venom in 55 minutes. Tests on sera from snake bite patients showed detectable levels of snake venom in the serum even though administration of antivenom was not necessary. Furthermore, results from these clinical cases were obtained in less than 45 minutes. It was found that the most suitable washing media was saline/Tween, the assay could be performed at room temperature and plates stored for 6 months showed no loss of activity.

Dengue hemorrhagic fever in Malaysia: the 1973 epidemic

The first major Malaysian epidemic of dengue hemorrhagic fever with severe manifestations occurred in 1973, with 969 reported cases and 54 deaths. In a detailed study of 138 clinically diagnosed and laboratory confirmed cases at the General Hospital in Kuala Lumpur, hemorrhagic manifestations were observed in 68.7% and shock in 18.1% of the patients. The cases occurred mainly from May to September, largely in urban and suburban areas of the majority of the states in the country. A main focus of infection was Jinjang, a heavily populated outlying district of Kuala Lumpur, where unusually high incidences of morbidity, severe disease and mortality were seen. Severe disease was seen mostly in children under the age of 15 years, although a significant number of adults suffered milder illnesses. The Chinese population was chiefly affected, due to their living in crowded, low-income housing where the vector, Aedes aegypti, occurred in the greatest numbers. All four dengue types were recovered during the epidemic period, although dengue 3 (DEN-3) was incriminated as the major epidemic type. Entomological data revealed high indices of A. aegypti throughout the country and left little doubt that this epidemic was aegypti transmitted. Spraying and fogging operations were carried out in attempts to control vector populations.

Acupuncture--effect on normal subjects

The effect of acupuncture analgesia on pain threshold was assessed in a group of 60 healthy volunteers. On the average a 60% elevation of the pain threshold was achieved. This effect was seen bilaterally with unilateral acupuncture stimulation. There was no significant difference in the effect produced by three widely separate sites of acupuncture stimulation. The possibility of an additive effect when two sites were simultaneously stimulated was not confirmed in our limited study. Evidence is presented that sensory nerve fibre stimulation may be the basic primary requirement of successful acupuncture analgesia.