EPA Consensus Project Paper: The Vertical Dimension of Occlusion. How to Determine and How to Alter? A Systematic Review.

PURPOSE: The aim of this systematic review was to explore the dental literature to identify high quality clinical studies that introduced methods of determining the vertical dimension of occlusion (VDO), and additionally to find studies which assessed alterations in the VDO. MATERIALS AND METHODS: An electronic search of the literature was conducted through PubMed , Embase, and Cochrane Library databases referring to the determination and alteration of the VDO by 12/2021. RESULTS: A total of 215 records were obtained from the initial search. After the first two screenings, 33 studies were selected for inclusion. Correlations in the morphometric group ranged between r=0.18-0.87, p⟨0.05-0.001, correlations in the cephalometric group ranged between r=0.28-0.92, p⟨0.05-0.001, and correlations in the mechanometric group ranged between r=0.21- 0.75, p⟨0.05-0.01. Regarding the alteration of VDO, in all studies the increase ranged between 1.8-8 mm and the patients adapted . CONCLUSIONS: No clear guidelines can be established yet, in relation to the determination and alteration of the VDO. There is no apparent benefit in using more invasive and complex methods compared to the use of the facial anatomical landmarks. Patient adaptation seems to be successful when the range of VDO increase was 1.8-6.0 mm.

The Effect of Denture Adhesives on Denture Quality and Occlusal Force.

INTRODUCTION: Complete dentures (CDs) have been associated with substantial problems regarding edentulous patient's function. Denture adhesives seem to be useful adjuncts to improving retention and stability. METHODS: A clinical study was undertaken to investigate the effect of a denture adhesive (DA) on function in complete denture wearers along with the quality of their CDs. Thirty complete denture wearers participated in the study. The first phase of the experimental procedure comprised 3 groups of measurements performed at 3 distinct time points: the initial measurement (T1), a 2nd measurement after 15 days of DA daily application (T2), and a 3rd measurement following a 15-day washout period (T3). The second phase consisted of the follow-up measurements. The measurements included: recording of relative occlusal force (ROF), distribution of occlusal contacts (DOC) and center of force (COF) using the T-Scan 9.1 device and functional assessment of dentures using the FAD index. RESULTS: The DA use induced a statistically significant increase in ROF (p-value=0.003) and decrease in COF (p-value⟨0.001) and DOC (p-value=0.001). The overall FAD score significantly improved (p-value⟨0.001). CONCLUSIONS: The use of the DA improved the occlusal force, the distribution of occlusal contacts as well as the qualitative characteristics of CDs.

Factors Affecting Decision-Making For Congenitally Missing Permanent Maxillary Lateral Incisors: A Retrospective Study.

The aims of this study were as follows: 1) to retrospectively evaluate clinical situations of patients with congenitally missing permanent maxillary lateral incisors (CMPMLI) who were referred to three dental clinics specialised in prosthodontics over a 14-year period and 2) to investigate the factors affecting decision-making for patients with CMPMLI. The records of 46 patients with CMPMLI who were treated over a period of 14 years were examined to determine the mechanism of decision-making for treatment planning and factors affecting the decision. Descriptive statistics were used in the initial analysis of the entire data set. In addition, a correlation coefficient-the nonparametric Spearman's rho coefficient-was calculated to trace any possible relation between variables or rank orders. The significance level was set at 0.05 for the analysis. The results of this study revealed that decision-making for treatment of CMPMLI is directly dependent mainly on the following four factors: 1. Patient's age at treatment commencement 2. Individual characteristics of each clinical situation, which play a crucial but not an exclusive role in the treatment approach 3. Synthesis of the participating specialists in the treating team, which plays a crucial role in the decision-making 4. Use of pin-retained resin-bonded bridges (RBBs), either bilaterally attached or cantilevered, proved to be a reliable solution in terms of aesthetics, function and soft tissue response during the study period. Clinical implication: The rationale in the decision-making process for patients with congenitally missing permanent maxillary lateral incisors was investigated in this study to determine whether specific treatment options are superior to others.

The Effect of Surface Preparation of Acrylic Teeth.

PURPOSE: To investigate whether the chemical bond between acrylic teeth and heat polymerized PMMA can be altered by chemical and/or mechanical treatment. MATERIALS AND METHODS: One hundred fifty acrylic teeth were divided in groups of 10. Their ridge lap surface underwent mechanical and/or chemical treatments: 1) no treatment, 2) air-abrasion with Al2O3 particles, 3) acid etching with phosphoric acid, 4) application of composite resin bonding agent, 5) application of MMA and ethylmethylketone bonding agent, 6) PMMA monomer application. The teeth were then placed in heat polymerized acrylic resin. Each specimen was compressed with a universal testing machine. Descriptive statistics, one-way ANOVA (α=0.05) and Tukey's HSD test were used. A scanning electron microscope (SEM) was also used to study the fracture areas. RESULTS: Statistically significant differences (p⟨0.001) in the bond strength were found. The strongest bond (239.41 N), was noted in the group treated with sandblasting followed by PMMA monomer application. CONCLUSIONS: Mechanical and/or chemical preparations affect significantly the bond strength between the acrylic resin denture teeth and the PMMA denture base. Air abrasion was the most effective treatment, either alone or combined with other treatments.

Evidence-based care and the curriculum.

An evidence-based (EB) approach has been a significant driver in reforming healthcare over the past two decades. This change has extended across a broad range of health professions, including oral healthcare. A key element in achieving an EB approach to oral healthcare is educating our practitioners, both current and future. This involves providing opportunities integrated within simulated and actual clinical settings for practitioners to learn and apply the principles and processes of evidence-based oral healthcare (EBOHC). Therefore, the focus of this discussion will be on ways in which EBOHC and associated research activities can be implemented into curricula, with the aim of improving patient care. This paper will initially define the scope of EBOHC and research, what these involve, why they are important, and issues that we need to manage when implementing EBOHC. This will be followed by a discussion of factors that enable successful implementation of EBOHC and research into curricula. The paper concludes with suggestions on the future of EBOHC and research in curricula. Key recommendations related to curricula include strengthening of the culture of a scientific approach to education and oral healthcare provision; complete integration of EBOHC into the curriculum at all levels; and faculty development to implement EBOHC based on their needs and evidence of effective approaches. Key recommendations to support implementation and maintenance of EBOHC include recognition and funding for high-quality systematic reviews and development of associated methodologies relevant for global environments; building global capacity of EBOHC researchers; research into improving translation of effective interventions into education and healthcare practice, including patient-reported outcomes, safety and harms, understanding and incorporation of patient values into EB decision-making, economic evaluation research specific to oral healthcare and effective methods for changing practitioner (faculty) behaviours; and extend access to synthesized research in 'user friendly' formats and languages tailored to meet users' needs. Realizing these recommendations may help to improve access to effective healthcare as a basic human right.

Validation of communication between elderly denture wearers and dentists: a questionnaire on satisfaction with complete dentures using semi-structured interviews.

OBJECTIVES: To validate a semi-structured interview (SSI) for communication between complete denture wearers and dentists. DESIGN: A SSI using a questionnaire with eight questions on satisfaction with complete dentures (CD): covering function, aesthetics and comfort. The first seven questions used a five-point Likert scale and the last was dichotomous. Two dentists, carefully trained in the use of the structured questionnaire, administered the SSI. SETTING: A Greek Department of Prosthetic Dentistry. SUBJECTS: A consecutive sample of 78 CD wearers took part in the study. All subjects presented with complaints from their dentures. INTERVENTION: All participants and their dentures underwent clinical examination. RESULTS: The method showed good reliability, verified by the Cronbach alpha (0.86). Both dentists used the questionnaire produced very similar results. (Wilcoxon test 61-99%). Further, the association of the answers with respect to the five-point Likert scale was very high; all gamma coefficients were statistically significant except for pain and discomfort from the upper CD (CDU). CONCLUSIONS: This method of communication between patients and dentists is reliable and can be used to give good repeatability for qualitatively assessing satisfaction with CD. It can be valuable for clinical use and for extending the study of denture quality to establish outcome measures based on the subjective criteria of satisfaction.

Cement failure loads of 4 provisional luting agents used for the cementation of implant-supported fixed partial dentures.

The major disadvantage of cement-retained implant-supported fixed partial dentures (FPDs) is difficulty in retrievability. The retentive strengths of the provisional luting agents usually employed in these cases are therefore an important consideration. This study evaluated the cement failure loads of 4 provisional luting agents used for the cementation of FPDs supported by 2 implants or 4 implants. Nogenol luting agent exhibited the lowest retentive values in both types of FPD. ImProv proved to be the most retentive cement of all tested. Temp Bond NE and Temp Bond presented significantly different values (P < .05) for the 2-implant FPD, but not for the 4-implant model. On the basis of the study results, it may be concluded that Nogenol appears to be more appropriate for cementation of both 2- and 4-implant-supported FPDs when removal of the provisionally cemented superstructure is anticipated.

Fabrication of a custom-made impression tray for making preliminary impressions of edentulous mandibles.

Severe mandibular alveolar ridge resorption is usually observed in patients with long-term edentulism and/or ill-fitting dentures. In some of these patients, the genial tubercles project into the floor of the mouth as a high point in the anterior area of the mandibular residual ridge. The lingual flanges of mandibular stock impression trays usually impinge on the most prominent areas of the resorbed mandibular edentulous ridge (i.e., internal oblique lines and genial tubercles). It is suggested that a preliminary custom tray be made in such cases to pour an initial impression so that individual custom trays can be fabricated. An efficient method for constructing such a custom impression tray from readily available materials is described.

An esthetic and hygienic approach to the use of intracoronal attachments as interlocks in fixed prosthodontics.

This article describes a procedure that uses the Ney MS (Minimal Space) intracoronal attachment as an interlock in a pontic. This procedure overcomes the disadvantages associated with the use of the intracoronal attachments, which are (1) excessive tooth reduction often required to place the attachment within the contour of the crown; (2) compromised embrasures, which result in oral hygiene and periodontal problems; and (3) poor esthetics.

Influence of tissue conditioning materials upon the crystalline structure of dental stone and improved dental stone.

Dental stone and improved dental stone were crystallised in contact with six commercial tissue conditioning materials. Their influence on the crystalline structure of dental stone and improved dental stone were investigated using a scanning electron microscope. Tissue conditioning materials cause horizontal orientation of the crystals of calcium sulphate CaSO4 2H2O dihydrate.

Retentive ability of various denture adhesive materials: an in vitro study.

This in vitro investigation of the retentive ability of various commercially available denture adhesives was performed by measuring the adhesion and cohesion that developed between a glass surface and an acrylic resin disk surface when some liquids, adhesive materials, or both were placed between them. Student's paired t-test, repeated measures, and two-factor design analysis of variance were performed to determine the significance among mean values. The adhesive materials studied exhibited a significantly greater retentive ability than that of saliva, and their retentive ability increased significantly when they were used in combination with artificial saliva. Highly significant differences of the retentive ability among the different brands of denture adhesives were observed.

Dimensional stability and reproduction of surface detail of tissue conditioning materials.

Four commercial tissue conditioners have been assessed in terms of their dimensional stability and ability to reproduce surface detail according to ADA specification #19 for impression materials. Results have been compared with those of a number of elastomeric impression materials. The tissue conditioners performed adequately and as such could be used as impression materials within 24 hours of their application. While they did not compare well with the elastomeric impression materials they comply with the limitations of the ADA specifications. It is suggested that standards specific to these materials should be developed.

Influence of tissue conditioners upon the surface hardness of dental stone and improved dental stone.

The surface hardness of dental stone and improved dental stone was investigated when crystallised in contact with tissue conditioners and compared with that observed when the two types of gypsum are crystallised in contact with impression materials used clinically. Vickers hardness tests were performed 45 minutes, 2 hours and 24 hours after the beginning of stone mixing. The tissue conditioners did not have adverse effects on the surface hardness of gypsum products. On the contrary, they gave casts with excellent surface hardness, as did the elastomeric impression materials.

Using cephalometry to evaluate maxillomandibular relationships in complete denture construction.

Long-term denture wearers undergo facial changes as a result of occlusal wear of the dentures and residual ridge resorption. This study examined 12 such patients, presenting with a clinical appearance of Angle's Class III occlusal relationships, to evaluate a clinical method of determining the correct mandibular position. Complete dentures were fabricated for each patient using standard clinical procedures, but acrylic resin blocks were left on the mandibular posterior bases instead of denture teeth. Ensuing changes in maxillomandibular relationships were recorded. After the stabilization of the mandibular relationship, the dentures were completed using mandibular posterior teeth. Patients were evaluated using cephalometric analysis before and after treatment. Results show that a careful procedure of denture fabrication allows the determination of the correct mandibular relationship, even in patients who have experienced extreme facial collapse.

Perforated diverticulitis: a surgical dilemma.

Thirty-eight patients, 18 males and 20 females (mean age 61 years) have been operated on for perforated diverticulitis, over the past 14 years. We assigned the patients into stage A (n = 12) when the inflammation was confined to the mesosigmoid folds, stage B (n = 16) when an intraabdominal abscess was walled off and stage C (n = 10) when a generalized peritonitis had developed. Resection of the perforated sigmoid was carried out in 24 patients either as Hartmann's procedure (n = 18) or with primary anastomosis (n = 6). The mortality rate in this setting was 0.0% and 16.6% respectively. In 14 patients, no resection was carried out in 24 patients either drainage and colostomy (n = 10) or only drainage (n = 4) with corresponding mortality rate 30% and 25%. Mortality rate in relation to the stage was: Stage A 16.16%, Stage B 12.5% and Stage C 10%. The higher mortality rate in stage A and B was due to the fact that less radical operations were carried out. Four of our five deaths in all stages occurred in patients in whom the perforated sigmoid was not resected. In conclusion resection of the perforated sigmoid with or without primary anastomosis regardless of the stage of the disease is recommended.

[Changes of the elastomer impression materials after their immersion in some disinfection agents for AIDS infection control purposes]. / Eumperiphora ton elastomeron apotypotikon ylikon kata ton apolymanse enanti tou iou tou AIDS se merika aposteirotike--apolymantika kai antiseptika ygra.

In achieving infection control in the dental office and the dental laboratory it has been suggested that impressions made in the dental office should be disinfected before they are send to the dental laboratory. In this study we examined the solubility and the linear changes of some elastomer impression materials after their immersion in disinfection agents after ten, twenty and forty minute time intervals. The disinfection agents used were: 75% alcohol, domestic chlorine 10%, the agent sterile pack (isopropyl alcohol) and 2% activated glutaraldehyde (SIDEX). Water was used as control. Our findings show that all types of elastomer impression materials appear to suffer insignificant changes both linear and weight-wise but polyether impression materials show significant changes in almost all the disinfection agents that were used and the time intervals that were studied.