Development of an optimal relief method for the palatal plate by stress analysis

Background Plate dentures cannot be easily modified after fabrication; therefore, the sites and magnitude of relief must be effectively assessed at the time of fabrication. However, a considerable variation exists in the magnitude of optimal relief and relief range, and there are no guidelines that present these clearly, leading the dentists to decide subjectively. Thus, this study aims to develop an optimal relief method to improve the stress bearing capacity of the palatal mucosa. Methods The objective of this study, namely, the borderline, was set in steps. A three-dimensional finite element model for the pseudopalatal plate was created and used to evaluate the changes in stress distribution in the palatal mucosa due to the selective relief of stresses above the borderline. The resulting data were used to develop the optimal relief method. Results In the relief model with a borderline of 0.04 MPa or higher, the distribution volume at which a high stress of 0.20 MPa or higher is generated was approximately 800% of that with the no-relief model, and in the relief model with a borderline of 0.06 MPa or higher, the respective ratio was approximately 280%. On the other hand, the relief models with a borderline of 0.14 MPa or higher were approximately 60%. In the mid-palatal relief model, the distribution volume at which a stress of 0.20 MPa or higher was generated was 180% of that in the relief model. Conclusions The supportive strength of plates can be increased by selectively applying optimal relief rather than standard relief, allowing for easier and more effective plate-denture treatment.

Development of an Optimal Relief Method for the Palatal Plate by Stress Analysis

Background: A maxillary-palate-shaped device for simultaneous measurement of bite force and palatal mucosal subsidence at the time of pain onset in dentate persons has been developed. However, palatal mucosal stress analysis in a simulation based on three-dimensional finite element analysis is effective for objective and efficient evaluation of various types of denture-supporting mucosa. Recently plate dentures are not easily modified after the completion of these dentures , so it is essential to effectively assess the sites and magnitude of relief at the time of preparation. However, there is considerable variation in the magnitude of optimal relief and relief range, and there are no guidelines that present these clearly, leading the surgeon to decide subjectively. Thus, this study aimed to develop an optimal relief method to improve the stress bearing capacity of the palatal mucosa.Objectives: The objective of this study, the borderline was set in steps. The changes in stress distribution in the palatal mucosa due to the selective relief of stresses above the borderline were evaluated using a three-dimensional finite element simulation. The purpose of this study was to develop an optimal relief method to improve the bearing capacity of the palatal mucosa.Methods: The objective of this study, the borderline, was set in steps. A three-dimensional finite element model for the pseudopalatal plate was prepared and used to evaluate the changes in stress distribution in the palatal mucosa due to the selective relief of stresses above the borderline. The resulting data were used to develop the optimal relief method.Results: In the relief model with a borderline of 0.04 MPa or higher, the distribution volume at which high stress of 0.20 MPa or higher is generated was approximately about 800%％ of that with the no-relief model, and in the relief model with a borderline of 0.06 MPa or higher, the respective ratio was approximately about 280％%. On the other hand, the relief models with borderline of 0.14 MPa or higher were about 60%. In the mid-palatal relief model, the distribution volume at which stress of 0.20 MPa or higher was generated was 180% of that in the relief model.Conclusions: The supportive strength of plates can be increased by selectively applying optimal relief rather than standard relief, allowing for easier and more effective plate-denture treatment.

Changes in denture retention with denture adhesives and oral moisturizers for the oral cavity: an in vitro study

Background It is difficult to maintain complete dentures during meals in place. This in vitro study aimed to assess changes in denture retention between rest and function using denture adhesives and oral moisturizers in an oral cavity model. Methods The following test samples were applied between the palatal plate and the edentulous jaw ridge model: denture adhesive, denture adhesive for dry mouth, oral moisturizer, and denture moisturizer. The retentive force was measured under two conditions: at rest while immersed in water and during function with a 2.5-kg load applied. The plate was pulled perpendicular to the occlusal plane and the retentive force was measured using a digital force gauge. Results Under dry conditions, denture adhesive for dry mouth and oral moisturizer had a significantly higher retentive force than denture adhesive and denture moisturizer. After 30 min of immersion in water, the retentive force of the denture adhesive increased while that of the oral moisturizer decreased. After 30 min of function, the retentive force of the denture adhesive and denture adhesive for dry mouth remained high, while that of the oral moisturizer and denture moisturizer significantly decreased. Between rest and function, the retentive force of the denture adhesive and denture adhesive for dry mouth was high, and that of the oral moisturizer was low. Conclusions Immediately after use, denture adhesive for dry mouth exhibited high retentive force, but retention gradually decreased due to its water content.

Retrospective study on growth in infants with isolated Robin sequence treated with the Tuebingen Palate Plate

Background Children with Robin sequence (RS) are at risk of growth failure, mainly due to their increased work of breathing and feeding difficulties. Various conservative and surgical treatment approaches exist, but their impact on weight gain has not yet been adequately addressed. A functional treatment concept, used in our center for > 20 years, includes a pre-epiglottic baton plate (Tuebingen palatal plate) and intensive feeding training. Objective To investigate the effect of the Tuebingen treatment protocol on growth and weight trajectories during infancy. Methods This retrospective study analyzed longitudinal data from infants with isolated RS admitted to Tuebingen University Children’s Hospital, Germany between 1998 and 2019. Through our electronic patient database, we evaluated anthropometric parameters until reaching 1-year follow-up. Results are shown as median (IQR). Results In 307 infants analyzed, median Z-score for weight decreased from − 0.28 at birth to − 1.12 upon admission to our center at a median age of 22 days. Z-score then remained largely unchanged until discharge (Z-score difference, − 0.08), while the proportion of infants receiving tube feedings decreased from 55.1 to 13.7%. Z-score subsequently increased from − 1.17 at discharge to − 0.44 at the 1-year follow-up (p < 0.001). Conclusion Based on a comparatively large cohort, this functional treatment was associated with better weight gain and improved feeding. As RS infants often show postnatal growth failure, weight monitoring may be a valuable parameter for monitoring treatment effectiveness. Clinical Trial Registration Not necessary due to the retrospective design.

Accuracy Evaluation of Additively and Subtractively Fabricated Palatal Plate Orthodontic Appliances for Newborns and Infants–An In Vitro Study

Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100 µm layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.

Accuracy Evaluation of Additively and Subtractively Fabricated Palatal Plate Orthodontic Appliances for Newborns and Infants – An In-vitro Study

Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100&micro;m layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.

Changes in Denture Retention With Denture Adhesives and Oral Moisturizers for the Oral Cavity

Background: It is difficult to maintain dentures during meals. This study aimed to assess changes in denture retention between rest and function using denture adhesives and oral moisturizers in an oral cavity model.Methods: The following test samples were applied between the palatal plate and the edentulous jaw ridge model: denture adhesive, denture adhesive for dry mouth, oral moisturizer, and denture moisturizer. The retentive force was measured under two conditions: at rest while immersed in water and during function with a 2.5-kg load applied. The plate was pulled perpendicular to the occlusal plane and the retentive force was measured using a digital force gauge.Results: Under dry conditions, denture adhesive for dry mouth and oral moisturizer had a significantly higher retentive force than denture adhesive and denture moisturizer. After 30 min of immersion in water, the retentive force of the denture adhesive increased while that of the oral moisturizer decreased. After 30 mins of function, the retentive force of the denture adhesive and denture adhesive for dry mouth remained high, while that of the oral moisturizer and denture moisturizer significantly decreased. Between rest and function, the retentive force of the denture adhesive and denture adhesive for dry mouth was high, and that of the oral moisturizer was low.Conclusions: Immediately after use, denture adhesive for dry mouth exhibited high retentive force, but retention gradually decreased due to its water content. Clinical Significance: Denture adhesives for dry mouth can be useful for retaining dentures during 30-min meals.