Fit and retention of complete denture bases: Part II - conventional impressions versus digital scans: A clinical controlled crossover study

STATEMENT OF PROBLEM

Although the intraoral scanning of edentulous ridges is feasible, clinical evidence that the resulting denture retention is equivalent to that achieved with conventional impressions is lacking.

PURPOSE

The purpose of this clinical study was to determine the retention of complete denture bases fabricated from digital intraoral scans versus conventional impressions by using border molding and posterior palatal seal compression.

MATERIAL AND METHODS

Twenty volunteers with an edentulous maxilla were recruited. An intraoral scan of the maxilla and a conventionally border-molded impression with a custom tray were made. The conventional impression was poured; the definitive cast was scanned. Three-dimensionally (3D) printed (PB1) and milled bases (MB1) were fabricated based on the scan of the definitive cast. Based on the intraoral scan, a 3D printed (PB2) and a milled base (MB2) were fabricated. On each base, a platform with a hook consisting of a central notch orienting the force against the post dam (PD) and 2 lateral notches orienting the forces against the left (LT) and right (RT) tuberosities was set in the center of the outer surface of the base. A traction dynamometer was inserted in the hook and oriented into the corresponding notch by applying force until dislodgement. All bases were subsequently stored in artificial saliva for 2 weeks and scanned. Retention testing was repeated by using the same procedure. To evaluate trueness and to visualize the differences on a color map, the scan of the definitive cast and the intraoral scans were matched and compared in 3 dimensions. The Wilcoxon tests were used to compare the retention of the different bases (95% confidence interval, α=.05).

RESULTS

Nineteen participants with a mean ±standard deviation age of 64.1 ±14.7 years completed the 4 study sessions. The retention of printed bases (PD: 16.08 ±15.28 N; LT: 14.98 ±14.72 N; RT: 11.28 ±9.57 N) and milled bases (PD:14.52 ±17.07 N; RT: 11.99 ±12.10 N; LT: 13.55 ±15.53 N) fabricated from conventional impressions presented significantly higher retentive forces than those printed (PD: 6.21 ±4.72 N; RT:5.12 ±2.78 N; LT: 4.45 ±2.77 N) and milled (PD: 6.58 ±4.92 N; RT: 4.65 ±2.63 N; LT: 5.02 ±3.58 N) from the intraoral scans (P<.05). The differences were significant in all directions of dislodgement, as well as after storage in artificial saliva for 2 weeks. Comparison of the 3D distances between the intraoral scan and the definitive cast revealed a mean deviation of 0.45 ±0.11 mm.

CONCLUSIONS

Conventional impressions of the edentulous maxilla, including the clinical steps of border molding and posterior palatal seal compression, provide better retention than digital intraoral scans with both milled and 3D printed denture bases.

Fit and retention of complete denture bases: Part I - Conventional versus CAD-CAM methods: A clinical controlled crossover study

STATEMENT OF PROBLEM

Clinical evidence is sparse on whether dentures fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) methods afford superior fit and retention when compared with those fabricated conventionally.

PURPOSE

The purpose of this clinical controlled crossover study was to evaluate the peak retention force and fit of CAD-CAM manufactured (3D printed and milled) maxillary complete denture bases and conventional heat-polymerized bases (control).

MATERIAL AND METHODS

Twenty participants with edentulous maxillary arches were recruited. Impressions were made with a border-molded custom tray, and the resulting definitive cast was scanned. The conventional base was manufactured on the definitive cast with a hook and a 45-degree platform with a central notch and 2 lateral notches. The scan of the definitive cast was used for the fabrication of a milled and a printed base. The platform and hook position on the conventional base were transferred digitally to the milled and printed bases. All bases were scanned. A traction dynamometer was orientated into the notches, and retention was evaluated in the post dam and tuberosity areas. Scans were imported into a comparison software program which matched scans to their corresponding reference and performed a 3-dimensional comparison. The Friedman and Wilcoxon tests were used to compare between groups (confidence interval: 95%, α=.05).

RESULTS

Nineteen participants with a mean ±standard deviation age of 64.1 ±14.7 years completed all clinical sessions. No significant difference in peak retention was measured between milled (MB1), printed (PB1), and conventional (CB) bases in the post dam (CB: 12.44 ±9.62 N, PB1: 16.08 ±15.28 N, MB1: 14.52 ±17.07 N) and right tuberosity area (CB: 8.99 ±7.82 N, PB1: 11.28 ±9.57 N, MB1: 11.99 ±12.10 N). In the left tuberosity area, peak retention was lower for CB (10.03 ±8.39 N) than PB1 (14.98 ±14.72 N) and MB1 (13.55 ±15.53 N; P=.05). Compared with the definitive cast, the fit of the conventional base (0.18 ±0.01 mm) was closer than the printed (0.21 ±0.03 mm) and milled bases (0.21 ±0.02 mm) (P<.001).

CONCLUSIONS

The CD bases manufactured by CAD-CAM techniques provided retention and fit similar to that of conventionally manufactured bases and can therefore be considered suitable techniques.

Influence of age, training, intraoral scanner, and software version on the scan accuracy of inexperienced operators

PURPOSE

To evaluate the effect of operator age on the scan accuracy (trueness and precision) of inexperienced operators when compared with experienced operators, and how training, intraoral scanner (IOS), and software version affect scan accuracy.

MATERIAL AND METHODS

Thirty-four operators were sorted into groups: G1 (operators <25 years old, no experience), G2 (operators >40 years old, no experience), and G3 (experienced IOS operators). They conducted partial-arch scans before and after a 4-session training with two IOSs (Trios 3 and True Definition) and two software versions. These scans were compared with the reference scans obtained from conventional impressions and a laboratory scanner (IScan D103i) to evaluate trueness (mean root mean square values) and precision (standard deviation of root mean square values) with a software program (Geomagic Control X). Kruskal-Wallis and post-hoc Dunn's tests were used to evaluate the effect of age on the scan accuracy of inexperienced groups when compared with experienced operators, while the effect of training, IOS, and software version on scan accuracy was evaluated with Wilcoxon or Mann-Whitney U tests (α = 0.05).

RESULTS

Before training, G1 and G2 scans had similar accuracy (p ≥ 0.065). After training, G1 scans had higher accuracy when IOS data was pooled and had higher precision with TD (p ≤ 0.004). Training increased the scan accuracy (p < 0.001), while newer software increased the trueness of inexperienced operator scans (p = 0.015).

CONCLUSIONS

Age affected the scan accuracy of inexperienced operators after training, indicating that extended training may be required for older operators. Training increased the scan accuracy, and newer software increased the trueness of inexperienced operator scans.

Accuracy of Intraoral Scanner for Recording Completely Edentulous Arches-A Systematic Review

Scanning edentulous arches during complete denture fabrication is a crucial step; however, the quality of the resulting digital scan is still questionable. The purpose of this study is to systematically review studies (both clinical and in vitro) and determine whether intraoral scanners have clinically acceptable accuracy when recording completely edentulous arches for the fabrication of removable complete dentures. An electronic search in medical databases like PubMed, Scopus, and Web of Science (WOS), using a combination of relevant keywords, retrieved 334 articles. After full-text evaluation, twelve articles fulfilled the inclusion criteria for this review (eight clinical studies and four in vitro studies). A quality analysis of the included studies was carried out using the QUADAS-2 tool. The accuracy values varied between different intraoral scanners. Different regions of the edentulous arches showed differences in trueness and precision values in both in vitro and clinical studies. Peripheral borders, the inner seal, and poorly traceable structures like the soft palate showed maximum discrepancies. The accuracy of intraoral scanners in recording clear anatomic landmarks like hard tissues with attached mucosa was comparable to conventional edentulous arch impressions. However, higher discrepancies were recorded when digitizing mobile and poorly traceable structures. Intraoral scanners can be used to digitize denture-bearing areas, but the interpretation of the peripheral border and the soft palate should be carefully carried out.

Three tests to determine a preferred chewing side in partially edentulous patients: A pilot study

STATEMENT OF PROBLEM

Determining the preferred chewing side may be an important factor in prosthetic treatment planning, especially where additional support for a removable dental prosthesis can be provided by implants.

PURPOSE

The purpose of this clinical study was to investigate the validity and reproducibility of 3 different tests to determine the preferred chewing side.

MATERIAL AND METHODS

A total of 82 partial denture wearers, with an average age of 70 years, were enrolled in this study. The first test (CG) evaluated the left or right position of a piece of chewing gum after spontaneous mouth opening during mastication. A second test (ASI) videotaped 30 seconds of mastication and analyzed the distribution of masticatory cycles by means of an asymmetry index. For the third test (VAS), participants were asked to mark their subjective perception of their preferred chewing side on a visual analog scale representing the right and left sides. All the tests were performed and repeated in a randomized sequence. The reproducibility of the tests was first evaluated. The mean values of the ASI and VAS tests were calculated, and the results were compared with the second series of the CG test. The Pearson correlation test was used to associate ASI and VAS, and the Cohen kappa agreement was used for the inter-reliability of CG (α=.01).

RESULTS

The results indicated fair to almost perfect reproducibility for the 3 tests. Kappa values were.37 (P<.01) for the CG,.47 (P<.01) for the ASI and.91 (P<.01) for the VAS. Correlation coefficients resulted in rho=.86 (P<.01) for the ASI and rho=.97 (P<.01) for the VAS. The correlation between ASI and VAS was excellent, with rho=.85 (P<.010). CG and ASI (test kappa=.36, P<.010) and CG and VAS (test kappa=.39, P<.010) showed fair agreement.

CONCLUSIONS

ASI and VAS seem more reliable than CG to determine a patient's preferred chewing side and might be helpful within the context of prosthetic treatment planning, where additional support may improve denture function.

The Impact of Xerostomia on Food Choices-A Review with Clinical Recommendations

Xerostomia and hyposalivation are highly prevalent conditions in old age, particularly among multimorbid elders, and are often attributed to the use of multiple medications. These conditions negatively affect oral functions, such as chewing, swallowing, speech, and taste. Additionally, the lack of lubrication of the oral mucosa frequently leads to super-infections with candida. Denture retention and comfort may also be compromised. The risk of dental caries and erosion of natural teeth increases since saliva, which is essential for repairing initial lesions in tooth structures, is insufficient. The dry sensation in the mouth also impacts the emotional and social well-being of elderly individuals. Patients experiencing xerostomia often avoid certain foods that are uncomfortable or difficult to consume. However, some foods may alleviate the symptoms or even stimulate salivation. This review discusses the limited available evidence on nutritional advice for patients with xerostomia and aims to provide insight into the patient's perspective while offering clinical recommendations. Future studies should focus on investigating the nutritional intake of individuals suffering from xerostomia or hyposalivation in order to ensure oral health comfort, prevent malnutrition, and minimize the impact on their quality of life.

Exploring preferences of older adults for dental services: A pilot multi-national discrete choice experiment

OBJECTIVES

To pilot an exploration of older adults' future preferences using discrete choice experiments to understand who should provide dental examinations and treatment, where these services should be provided, and participants' willingness to pay and willingness to travel.

BACKGROUND

The proportion of older adults in the general population is increasing and is recognised as a pressing public health challenge.

MATERIALS AND METHODS

Older people aged 65 years and over were recruited into this study from the UK, Switzerland and Greece. Drawing on earlier stakeholder engagement, a set of choice experiments are developed to explore the future preferences of older people for dental examinations and dental treatment, as they anticipated losing their independence. These were presented to the participants using a range of platforms, because of the COVID pandemic. Data were analysed in STATA using a random-effects logit model.

RESULTS

Two hundred and forty-six participants (median age 70 years) completed the pilot study. There was a strong preference across all countries for a dentist to undertake a dental examination (Greece: β = 0.944, Switzerland: β = 0.260, UK β = 0.791), rather than a medical doctor (Greece: β = -0.556, Switzerland: β = -0.4690, UK: β = -0.468). Participants in Switzerland and the UK preferred these examinations to be undertaken in a dental practice (Switzerland: β = 0.220, UK: β = 0.580) while participants in Greece preferred the dental examination to be undertaken in their homes (β = 1.172). Greek participants preferred dental treatment to be undertaken by a specialist (β = 0.365) in their home (β = 0.862), while participants from the UK and Switzerland preferred to avoid any dental treatment at home (Switzerland: β = -0.387; UK: β = -0.444). Willingness to pay analyses highlighted that participants in Switzerland and the UK were willing to pay more to ensure the continuity of future service provision at a family dental practice (Switzerland: β = 0.454, UK: β = 0.695).

CONCLUSION

Discrete choice experiments are valuable for exploring older people's preferences for dental service provision in different countries. Future larger studies should be conducted to further explore the potential of this approach, given the pressing need to design services that are fit for purpose for older people. Continuity of dental service provision is considered as important by most older people, as they anticipate losing their dependence.

Masticatory performance in oral function assessment: Alternative methods

BACKGROUND

Masticatory function declines with age or disease, implicating a poor chewing efficiency and an often-unconscious change for a less healthy, yet easy to chew diet. Timely screening of masticatory function may foster an early-onset diagnosis and potential treatment. The aim of this study was to compare alternative diagnostic tools for masticatory function to a Jelly-scan test.

MATERIALS AND METHODS

Patients aged 70 years and older who were hospitalised for rehabilitation were recruited for this study. A total of four different tests for masticatory function were administered. The Japanese Society of Gerodontology glucose extraction test (Jelly-scan) was used as reference to compare a colour-changing gum test (Gum1-colour) as well as a mixing ability test with a visual (Gum2-visual) and opto-electronical (Gum2-digital) analyses. Receiver operating characteristic (ROC) curves were used to establish the discriminative value, kappa-values were used to estimate individual agreements and correlations were verified using Spearman's tests.

RESULTS

Sixty-one patients (Men n = 23, Women n = 38) aged 82.4 ± 6.8 years participated in the experiments. The average number of natural teeth was 16.5 ± 10.5, 34.4% of the participants wore removable dentures. For all tests, the sum of sensitivity and specificity was >150%. All test correlated with Jelly-scan (absolute Rho >0.5). With Jelly-scan 51 participants (83.6%) were diagnosed with "masticatory hypofunction". After reducing the cut-off value of the test from 100 mg/dL to 65 mg/dL, only 33 participants (54%) fulfilled the diagnosis. This post-hoc analysis increased the sensitivity of the Gum2-tests and the agreement to kappa >0.5 for all three tests.

CONCLUSION

All three tests can be considered useful screening alternatives. In its original version, Jelly-scan may tend to over-diagnose masticatory hypofunction, hence a novel cut-off with better agreement between tests is suggested.

Oral function and nutritional status in non-acute hospitalised elders

Introduction

Malnutrition and risk of malnutrition continues to be a common finding in elders, yet its association with oral function in hospitalised patients remains unclear.

Material and methods

Patients aged 70 years or over who had been hospitalised for non‐acute rehabilitation were recruited. Nutritional risk was screened using the Mini‐Nutritional Assessment Short Form (MNA‐SF) and Nutritional Risk Screening (NRS) scores. Malnutrition was assessed according to the Global Leadership Initiative on Malnutrition (GLIM) criteria. All participants underwent the oral hypofunction test battery, evaluating oral hygiene, oral dryness, occlusal force, tongue‐lip motor function, tongue pressure, masticatory and swallowing function. Statistical analyses comprised Mann‐Whitney or Kruskal‐Wallis tests. Bivariate associations between categorical variables were tested using the Pearson chi‐square test; for continuous variables, the Spearman correlation was calculated. A P‐value < .05 was considered statistically significant.

Results

Sixty patients aged a mean 82.5 ± 7.0 years participated. Some 88.3% were diagnosed with oral hypofunction, and this was more common in older patients (P = .020). Analysing the 7 oral hypofunction tests as an interval variable (NiOF) revealed additional correlations with number of teeth (ρ = 0.477) as well as the nutritional risk, evaluated by the MNA‐SF (ρ = −0.284) and NRS (ρ = 0.317) scores. NiOF scores were higher among denture wearers (P = .003). GLIM did not confirm the correlation with NiOF. Biomarkers such as serum albumin and CRP were not associated with the NiOF score.

Conclusion

In this sample, the association between oral function and nutritional state is more obvious in nutritional risk scores than in the malnutrition diagnosis by GLIM.

Validation of a novel diagnostic tool for decreased tongue pressure

INTRODUCTION

Reduced tongue pressure may render eating and swallowing difficult. The purpose of this study was to investigate whether the tongue training device can also be used as a diagnostic device and whether its sensitivity and specificity are equal to the numerical tongue pressure measuring device.

MATERIAL AND METHODS

The target group is patients aged 70 years and over who are hospitalised for rehabilitation. Tongue pressure was measured by both, a tongue pressure measuring instrument and a tongue training tool. The diagnosis of the reduced tongue pressure was made with the tongue pressure measuring instrument and set the verified with the novel tongue training tool.

RESULTS

Sixty-two participants were included in the study. Forty-five were classified by the tongue pressure measuring device and 53 by the tongue training device as 'low tongue pressure'. Spearman correlation confirmed a positive correlation between the tongue pressure measuring device and the tongue training device r_s  = 0.800, p = 0.01 level (2-tailed). The tongue training device test identified sensitivity was 100%, and its specificity was 52.9%. The AUC of the ROC curve is 0.901.

CONCLUSION

The tongue training device seems a simple, safe and readily available alternative to the tongue pressure measuring device for the diagnosis of low tongue pressure, with an excellent sensitivity and very good specificity.

Pneumonia prevention in the elderly patients: the other sides

Pneumonia is one of the leading causes of morbidity and mortality from infection in elderly patients. The increased frequency of pneumonia among elderly subjects can be explained by the physiological changes linked to the progressive aging of the respiratory tree and the diminished immunological response. A spiral of event leads to frailty, infection and possible death; preventing pneumonia consists of controlling the risk factors. Dysphagia, which is associated with malnutrition and dehydration, is recognized as one of the major pathophysiological mechanism leading to pneumonia and its screening is crucial for the pneumonia risk assessment. The impairment in the oropharyngeal reflexes results in stagnation of foreign material in the lateral cavities of the pharynx which may then get aspirated repeatedly in the lungs and cause pneumonia. Pneumonia prevention starts with lifestyle modifications such as alcohol and tobacco cessation. A careful review of the risk-benefit of the prescribed medication is critical and adaptation may be required in elders with multiple morbidities. Respiratory physiotherapy and mobilization improve the functional status and hence may help reduce the risk of pneumonia. Maintaining teeth and masticatory efficiency is important if malnutrition and its consequences are to be avoided. Daily oral hygiene and regular professional removal of oral biofilm can prevent the onset of periodontitis and can avoid an oral environment favoring the colonization of respiratory pathogens than can then be aspirated into the lungs.

Effects of overnight storage conditions on conventional complete removable prostheses

PURPOSE

To evaluate the effects of overnight storage conditions on the dimensional stability and retention of prostheses, as well as the participant's subjective perception of these interventions.

MATERIALS AND METHODS

Subjects with maxillary complete prostheses (CRPs) were randomly assigned to receive two interventions in a crossover design: storing the CRPs overnight in a dry or wet environment with a cleansing tablet. The denture intaglio surface was scanned, and outcome measures were collected before each intervention (BLN), post ntervention (PIS), and after immersion in water for 15 minutes after the intervention (WOC). Dimensional changes were analyzed for the total surface, anterior flange, palate, and tuberosities. Retention force was measured using a dynamometer, and the participants' subjective assessment of comfort, fit, and retention of their CRPs were collected. After verifying normal distribution, paired t and Wilcoxon signed-rank tests were used to check for any statistical significance (α = .05).

RESULTS

Ten participants (mean age: 76.5 ± 5.9 y) were recruited in this study. Between BLN and PIS, the dimensional changes after dry intervention were significantly less than when stored wet for total surface (P = .009), anterior flange (P = .028), and the palate (P = .005). No difference was found between the effects of storage or washout interventions on objectively measured CRP retention. However, after WOC following dry storage, participants perceived a lower retention (P = .021), and a more comfortable palate after WOC following the wet intervention (P = .018).

CONCLUSION

For dimensional stability, dry overnight storage of removable prostheses can safely be recommended when indicated. Immersion in water for 15 minutes does not seem to add advantages.

Comparison of the accuracy of optical impression systems in three different clinical situations

PURPOSE

To investigate the differences in accuracy (trueness and precision) of five different optical impression systems.

MATERIALS AND METHODS

The accuracy of the following optical impression systems was tested: (1) CEREC Bluecam (BL; Dentsply Sirona), (2) CEREC Omnicam (OM, Dentsply Sirona); (3) PlanScan (PL; Planmeca); (4) True Definition Scanner (TD; 3M ESPE); and (5) Trios 3 (TR; 3Shape). A standard plastic study model represented a patient with a fully dentate maxilla (ANA-4 V CER, frasaco). Three clinical situations were simulated: Patient 1 (P1): fully dentate; Patient 2 (P2): anterior partial edentulism (two missing incisors); and Patient 3 (P3): posterior partial edentulism (P3) (missing premolar and molar). The models were scanned with a reference scanner (IScan D104i, Imetric), and the digitalized models were used as reference for all comparisons. Then, optical impressions were made for the three clinical scenarios (n = 10 per group).

RESULTS

In situation P1, the TD group provided the highest trueness (180.2 ± 46.3μm). In situation P2, the highest trueness was found in the TD (97.9 ± 27.6 μm) and TR (105 ± 9.5μm) groups, and in situation P3, TR had the highest trueness (P < .05) with a median RMS value of 76.2 ± 5.6 μm. In terms of precision, TR provided the highest precision (P < .05) in all three clinical situations, with RMS values 76.7 ± 26 μm for P1, 46.8 ± 14.1 μm for P2, and 39.7 ± 9.1 μm for P3.

CONCLUSION

Two optical impression systems (TR and TD) were superior to the other tested systems in most of the measurements. However, none of the tested systems was clearly superior with respect to both trueness and precision.

Exploring Older Swiss People's Preferred Dental Services for When They Become Dependent

The objective of this study was to explore the preferred dental services of older people for when they become dependent. It aimed to assess their preferred type of health care professional and location of dental service, and relate their preferences to their willingness to pay (WTP) and willingness to travel (WTT). Older people aged 65 years or older were invited to participate in a questionnaire-based discrete choice experiment (DCE), to measure preferences for dental examinations and treatment, defined by two attributes: type of professional and location of the activity. Hypothetical scenarios based attributes were displayed in a projected visual presentation and participants noted their personal preference using a response sheet. Data was analyzed using a random-effects logit model. Eighty-nine participants (mean age 73.7 ± 6.6 years) attended focus group sessions. Respondents preferred that the family dentist (β: 0.2596) or an auxiliary (β: 0.2098) undertake the examination and wanted to avoid a medical doctor (β: –0.469). The preferred location for dental examination was at a dental practice (β: 0.2204). Respondents preferred to avoid treatments at home (β: –0.3875); they had a significant preference for treatment at the dental office (β: 0.2255) or in a specialist setting (β: 0.1620, ns). However, the type of professional did not have a significant influence on overall preference. Participants with a low WTP preferred examination at home (β: 0.2151) and wanted to avoid the dental practice (β: –0.0235), whereas those with a high WTP preferred the dental office (β: 0.4535) rather than home (β: –0.3029). WTT did not have a significant influence on preference. The study showed that older people generally preferred receiving dental services in a dental practice or specialist setting, and would prefer not to be treated at home. Continuity of dental services provided by the family dentist should therefore be prioritized where possible and further studies should examine the role of domiciliary care at home.

Oral care knowledge, attitude and practice: Caregivers' survey and observation

OBJECTIVES

This study aims to assess caregivers' knowledge, perception and perceived barriers as well as their daily usual practice concerning oral care provision in a geriatric hospital.

METHODS

A semi-structured questionnaire was developed and administered to caregivers in a geriatric ward. Furthermore, oral care delivery to dependent and independent patients was clinically observed.

RESULTS

One hundred and fifty-two caregivers (60% nurses, 40% nursing aids) completed the survey (78% response rate). Clinical oral care was observed in 97 inpatients. Observations revealed that brushing was done in 94% of opportunities in independent patients but in only 55% of dependent patients. This corresponded to the frequency indicated in the questionnaire for independent elders (97%, n.s.), whereas it was significantly different for dependent elders (89%, P < .001). 95% of caregivers stated in the questionnaire never verifying self-administered oral care, whereas 12.3% were actually observed verifying intraorally its efficiency (P = .07 chi-squared test). 71% of the respondents stated storing the prostheses dry, and 8% stated that they reinserted it after cleaning. Caregivers' observation revealed that 35.1% of prostheses were reinserted in the mouth, indicating a significantly higher rate than in the questionnaire (P < .05). Respondents felt that their training to perform oral hygiene measures was suboptimal (VAS 48 ± 34.4). Patients verbally refusing oral care were stated as a barrier by 14% of respondents and were witnessed in 15.6% of observation opportunities (n.s).

CONCLUSION

Various measures, such as hospital health policy, improved logistics or advanced hands-on training, might help to converge the clinical practice towards the theoretical knowledge.

Edentulous jaw impression techniques: An in vivo comparison of trueness

STATEMENT OF PROBLEM

Simplified edentulous jaw impression techniques have gained popularity, while their validity has not yet been evaluated.

PURPOSE

The purpose of this clinical study was to compare the trueness of maxillary edentulous jaw impressions made with irreversible hydrocolloid (ALG), polyvinyl siloxane (PVS), PVS modified with zinc oxide eugenol (ZOE) (PVSM), and an intraoral scanner (TRI) with a conventionally border-molded ZOE impression (control).

MATERIAL AND METHODS

Twelve edentulous maxillary impressions were made with the impression techniques. The analog impressions were scanned using a laboratory scanner, imported into 3-dimensional comparison software, and superimposed against the corresponding control. Trueness was evaluated by calculating the effective deviation known as root mean square (RMS) for the entire surface (ES) and for specific regions of interest such as peripheral border, inner seal, midpalatal suture, ridge, and posterior palatal seal. The secondary outcomes for this study were the patients' perception of the impression techniques. Statistical analyses with the Wilcoxon tests were carried out (α=.05).

RESULTS

For ES, significant differences were found when comparing ALG (1.21 ±0.35 mm) with PVS (0.75 ±0.17 mm; P=.008), PVSM (0.75 ±0.19 mm; P=.012), and TRI (0.70 ±0.18 mm; P=.006) but not among the other groups. Significant differences were found for peripheral border when comparing ALG (2.03 ±0.55 mm) with PVS (1.12 ±0.32 mm; P=.006), PVSM (1.05 ±0.29 mm; P=.003), and TRI (1.38 ±0.25 mm; P=.008), as well as TRI and PVSM (P=.028). Significant differences were also found for inner seal when comparing ALG (0.74 ±0.36 mm) with PVSM (0.52 ±0.13 mm; P=.041), as well as TRI (0.8 ±0.25 mm) versus PVS (0.56 ±0.14 mm; P=.005) and PVSM (P=.005). The difference at the ridge was significant when comparing PVS (0.18 ±0.07 mm) with PVSM (0.28 ±0.19 mm; P=.015) but not among the other groups. A significant difference was also found for posterior palatal seal when comparing PVS (0.55 ±0.41 mm) with PVSM (0.60 ±0.43 mm; P=.034). Patient perceptions showed significantly better satisfaction scores for ALG (1.83 ±2.03) and PVS (3.17 ±2.40) than for TRI (4.08 ±2.71), PVSM (4.58 ±2.35), and ZOE (6.83 ±1.75).

CONCLUSIONS

Edentulous impressions made with PVS, PVSM, and TRI had similar deviations and may yield clinically acceptable results. Irreversible hydrocolloids are contraindicated for definitive impression making in completely edentulous jaws.

[Pneumonia of the elderly and its link to oral health]

Pneumonia is a frequent and serious disease among the elderly, often associated with functional and cognitive impairments, dysphagia, malnutrition and immunosenescence. Although the link between the oral hygiene and the risk of pneumonia has been established, the oral status and swallowing function are not routinely screened in the context of a geriatric assessment. Bacteria from oral plaque are regularly aspirated into the lungs and periodontitis induces a chronic inflammation favoring the oral and respiratory epithelial colonization with respiratory pathogens, hence facilitating infections. The poor oral health status and related masticatory impairment are often associated with malnutrition and dehydration. Patients are stranded in a vicious circle of respiratory infections and relapses. Prevention in form of oral health care and daily oral hygiene has proven to be effective.

Effect of grinding and polishing on roughness and strength of zirconia

STATEMENT OF PROBLEM

The clinical applications of high-translucency monolithic zirconia restorations have increased. Chairside and laboratory adjustments of these restorations are inevitable, which may lead to increased roughness and reduced strength. The influence of grinding and polishing on high-translucency zirconia has not been investigated.

PURPOSE

The purpose of this in vitro study was to compare the roughness averages (Ra) of ground and polished zirconia and investigate whether roughness influenced strength after aging.

MATERIAL AND METHODS

High-translucency zirconia disks were milled, sintered, and glazed according to the manufacturer's recommendations. Specimens were randomized to 4 equal groups. Group G received only grinding; groups GPB and GPK received grinding and polishing with different polishing systems; and group C was the (unground) control group. All specimens were subjected to hydrothermal aging in an autoclave at 134°C at 200 kPa for 3 hours. Roughness average was measured using a 3-dimensional (3D) optical interferometer at baseline (Ra1), after grinding and polishing (Ra2), and after aging (Ra3). A biaxial flexural strength test was performed at a rate of 0.5 mm/min. Statistical analyses were performed using commercial software (α=.05).

RESULTS

Group G showed a significantly higher mean value of Ra3 (1.96 ±0.32 μm) than polished and glazed groups (P<.001), which showed no statistically significant difference among them (GPB, 1.12 ±0.31 µm; GPK, 0.88 ±0.31 µm; C: 0.87 ±0.25 μm) (P>.05). Compared with baseline, the roughness of groups G and GPB increased significantly after surface treatments and after aging, whereas aging did not significantly influence the roughness of groups GPK or C. Group G showed the lowest mean value of biaxial flexural strength (879.01 ±157.99 MPa), and the highest value was achieved by group C (962.40 ±113.84 MPa); no statistically significant differences were found among groups (P>.05). Additionally, no significant correlation was detected between the Ra and flexural strength of zirconia.

CONCLUSIONS

Grinding increased the roughness of zirconia restorations, whereas proper polishing resulted in smoothness comparable with glazed surfaces. The results provide no evidence that grinding and polishing affect the flexural strength of zirconia after aging.

[Pulmonary lymphangioleiomyomatosis: From pathogenesis to management]

INTRODUCTION

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting mainly young women.

BACKGROUND

The respiratory manifestations are characterized by a progressive cystic destruction of the lung parenchyma. Extrapulmonary involvement includes benign renal tumours called angiomyolipomas and abdominal lymphatic masses called lymphangioleiomyomas. At the pathological level, the cellular proliferation found in LAM is in part due to the presence of mutations in the tumour suppressor genes TSC1 and TSC2 (Tuberous Sclerosis Complex). These mutations lead to the activation of the mTOR pathway, which is currently the main therapeutic target. mTOR inhibitors such as sirolimus or everolimus have shown a beneficial effect on the decline in pulmonary function and a reduction of angiomyolipoma size, but are necessary in only some patients.

PERSPECTIVES

LAM cells have migratory properties mediated by the formation of new lymphatic vessels. They are also able to secrete metalloproteases, which enhance their invasiveness. Moreover, the expression of estrogen and progesterone receptors by LAM cells suggests a possible role for sex hormones in the pathogenesis of the disease.

CONCLUSION

A better understanding of mTOR-independent mechanisms would allow the development of novel therapeutic approaches.

[Staphylococcus aureus broncho-pulmonary infections]

Staphylococcus aureus accounts for 2-5% of the etiologies of community-acquired pneumonia. These infections occur mainly in elderly patients with comorbidity, after a respiratory viral infection. S. aureus could also be responsible for necrotizing pneumonia, which occurs in young subjects, also after flu. Necrotizing pneumonia are associated with the production of a particular staphylococcal toxin called Panton-Valentine leukocidin, responsible for pulmonary focal necrosis, occurrence haemoptysis, leucopenia, and death. In Europe, these strains are still predominantly sensitive to anti-staphylococcal penicillin, which must be used at high dosage intravenously in combination with an antibiotic that reduces toxin production such as clindamycin, and intravenous immunoglobulin in severe cases. The mortality rate is estimated at 50%. In addition, S. aureus is one of the pathogens involved in early respiratory infections in cystic fibrosis patients, in whom methicillin resistance plays an important prognostic role. However, the involvement of S. aureus in COPD exacerbations is rare. Finally, S. aureus represents 20 to 30% of cases of hospital-acquired pneumonia, including ventilator-associated pneumonia. In these cases, methicillin-resistance is common and requires the use of glycopeptides or linezolid. The place of new anti-staphylococcal antibiotics such as new generation cephalosporins or tigecyclin remains to be defined.