The New Elderly Patient: A Necessary Upgrade

The elderly individual is becoming the most common patient in clinical practice due to the increasing average life span, especially in developed countries. The current elderly patients are different from those of some decades ago. They usually have an active social life, want to be informed, and are actively involved in the current society with consequent high expectations for medical and dental treatment. However, not all the elderly patients are like this. Some of them show limited financial resources, reduced mental and manual skills, and poor motivation. The purpose of this communication is to make a brief characterization of the new elderly population in view of prosthetic and dental management

Comparative analysis of the stability of prosthetic screws under cyclic loading in implant prosthodontics: An in vitro study

Background: To compare the loss of preload in absence of loading and after a fixed number of cyclic loadings on 7-mm distal cantilever in two different connection systems using all-on-four prosthetic model. Methods: Two equal models of an edentulous mandible rehabilitated with all-on-four technique with two types of abutment system (MUA and OT-Bridge) supporting a hybrid prosthesis, were used. Initial torque values of the prosthetic fixing screw, after ten minutes from initial screw tightening and after 400,000 repeated loadings were registered using a mechanical torque gauge. Differences between initial and final torque values were reported for each anchoring system and the two systems were finally compared. Results: No statistically significant differences regarding the loss of preload between MUA and OT-Bridge system were found after 400,000 cyclic loadings; however, in MUA system it was found between anterior and posterior implant screws. A significant difference in preload loss was found only for MUA system comparing the initial screw torque to that measured after 10 min from the tightening in absence of cyclic loadings. Conclusions: Within the limits of the present study, MUA and OT-Bridge may be considered reliable prosthetic anchoring systems able to tolerate repeated cyclic occlusal loads on distal cantilever in all-on-four rehabilitation model without any significant loss of preload in screw tightening

Complete-arch accuracy of four intraoral scanners: An in vitro study

The purpose of this study is to define the accuracy of four intraoral scanners (IOS) through the analysis of digital impressions of a complete dental arch model. Eight metal inserts were placed on the model as reference points and then it was scanned with a laboratory scanner in order to obtain the reference model. Subsequently, the reference model was scanned with four IOS (Carestream 3600, CEREC Omnicam, True Definition Scanner, Trios 3Shape). Linear measurements were traced on an STL file between the chosen reference points and divided into four categories: three-element mesiodistal, five-element mesiodistal, diagonal, and contralateral measurements. The digital reference values for the measurements were then compared with the values obtained from the scans to analyze the accuracy of the IOS using ANOVA. There were no statistically significant differences between the measurements of the digital scans obtained with the four IOS systems for any of the measurement groups tested

Bi-allelic Variants in the GPI Transamidase Subunit PIGK Cause a Neurodevelopmental Syndrome with Hypotonia, Cerebellar Atrophy, and Epilepsy

Glycosylphosphatidylinositol (GPI)-anchored proteins are critical for embryogenesis, neurogenesis, and cell signaling. Variants in several genes participating in GPI biosynthesis and processing lead to decreased cell surface presence of GPI-anchored proteins (GPI-APs) and cause inherited GPI deficiency disorders (IGDs). In this report, we describe 12 individuals from nine unrelated families with 10 different bi-allelic PIGK variants. PIGK encodes a component of the GPI transamidase complex, which attaches the GPI anchor to proteins. Clinical features found in most individuals include global developmental delay and/or intellectual disability, hypotonia, cerebellar ataxia, cerebellar atrophy, and facial dysmorphisms. The majority of the individuals have epilepsy. Two individuals have slightly decreased levels of serum alkaline phosphatase, while eight do not. Flow cytometric analysis of blood and fibroblasts from affected individuals showed decreased cell surface presence of GPI-APs. The overexpression of wild-type (WT) PIGK in fibroblasts rescued the levels of cell surface GPI-APs. In a knockout cell line, transfection with WT PIGK also rescued the GPI-AP levels, but transfection with the two tested mutant variants did not. Our study not only expands the clinical and known genetic spectrum of IGDs, but it also expands the genetic differential diagnosis for cerebellar atrophy. Given the fact that cerebellar atrophy is seen in other IGDs, flow cytometry for GPI-APs should be considered in the work-ups of individuals presenting this feature

The use of lithium disilicate in fixed dental prosthesis: from the adhesive interface to clinical performance

Chapter 1 is an introduction to lithium disilicate: its glass ceramic nature, its characteristics, its mechanical properties. The possibility to be etched allows lithium disilicate to be adhesively luted on dental tissues, influencing both the final properties of restoration and the clinical protocol of cementation. The aim of this thesis was investigate the adhesive interface between lithium disilicate, resin cement and dental tissues from different points of view: retention, fracture strength and survival rate. In Chapter 2 the retention of lithium disilicate crowns cemented using two different cementation systems was measured. Twenty extracted mandibular premolars were prepared. Anatomic crowns were waxed and hot pressed using lithium disilicate ceramic. Teeth were divided into two groups (n = 10): (1) self- curing luting composite and (2) glass-ionomer cement (GIC). After cementation, the crowns were embedded in acrylic resin block with a screw base. Each specimen was pulled along the path of insertion in Universal Testing Machine. Failure load in Newtons (N) and failure mode were recorded for each specimen. Failure mode was classified as decementation or fracture. Failure load data were analyzed using one-way analysis of variance (ANOVA). Failure modes were compared using Pearson’s Chi-square test. Mean failure load was 306.6(±193.8) N for composite group and 94.7(±48.2) N for GIC group (p = 0.004). Disilicate crown cemented with luting composite most often failed by fracture; otherwise, crown cemented with glass-ionomer cement most often failed by decementation (p = 0.02). Disilicate full crown cemented with luting composite showed higher failure load compared with conventional cementation with glass-ionomer cement. The interface between tooth, luting composite and lithium disilicate surface was also qualitatively evaluated using a scanning electron microscope (SEM). An extracted restoration-free human molar was stored in physiological solution until it was embedded in an autopolimerysing acrylic resin. A standard preparation for onlay was completed and after preparation an anatomic onlay was waxed on the tooth and then hot pressed using lithium disilicate ceramic. After cementation the sample was dissected using an Automatic Micromet (Remet s.a.s) and the section was analyzed using a SEM. SEM evaluation of the tooth showed the three layers seamlessly; by increasing the enlargement the interface did not change. In Chapter 3 the fracture strength of human teeth restored with lithium disilicate onlays, with and without fiber post build-up, was measured. Twenty human mandibular molars were horizontally sectioned and divided into two groups (n = 10). No treatment was applied in group A. Teeth in group B were endodontically treated, built-up using fiber post and composite core and prepared with a circumferential chamfer providing a 1 mm circumferential ferrule. Lithium disilicate onlays were pressed and luted on teeth using dual-curing luting composite. Teeth were tested under static load. Failures were classified as restorable or not restorable. Failure loads were analyzed with ANOVA. Failure modes were compared using Pearson’s Chi-square tests. The mean fracture loads were 1383.5 N for group A and 1286.3 N for group B. No difference was found (p = 0.6). Ninety per cent of fractures were classified as not restorable in both groups, with no difference (p = 0.8). It was concluded that, for teeth restored with adhesive procedures and lithium disilicate onlays, the presence of build-up with fiber post to provide retention and resistance form (as traditionally stated) does not influence the fracture strength. Finally, in Chapter 4, a retrospective study was conducted to assess the clinical performance of lithium disilicate single restorations adhesively cemented on natural teeth. All patients who received lithium disilicate single restorations between 2009 and 2013 at the dental clinic of the University of Ferrara were recalled for clinical evaluation. A total of 43 partial and total restorations in 17 patients were evaluated from a minimum of 36 months follow-up to a maximum of 81 months follow-up, with a mean follow-up of 51 months. The cumulative survival rate was 97.7%, and the cumulative success rate was 94.2%. Lithium disilicate can be successfully used for single-tooth restorations in both anterior and posterior regions, provided that an adhesive luting protocol is applied

Occlusal contacts are affected by experimental jaw muscle pain

Objective: Aim of the study was to measure the effect of an experimental jaw muscle pain on number and position of posterior occlusal contacts. Methods: Eleven adult voluntary subjects (nine male, two female, age 25.2±2.3) were enrolled in this randomized cross-over study. Each subject participated in two experimental sessions (separated by 30 days) in which he/she received an injection in the right masseter muscle. Subjects were randomized with respect to the sequence of the substance injected, hypertonic (5.0%) or isotonic saline solution (0.9%), used respectively as painful and control substance. Three occlusal bite records at the maximal intercuspal position were obtained during each experimental session: before (baseline), during and ten minutes after the end of injection. Occlusal records were put on lower casts and posterior contacts were reported by different colors (black for baseline, red for intermediate and green for final contacts) and counted. Difference in color was assumed to be difference in position, and the intermediate contacts were consequently classified as confirmed, disappeared or new contacts. Repeated measures ANOVA was used to compare the overall number of contacts among groups and the number of contacts of different colors. Results: Means and standard deviations of number of contacts are reported in table. No significant difference was found between the overall number of occlusal contacts, but a significant difference (p=.03) was found between contacts according to different colors. That means the overall number of contacts did not change, but the position did. Conclusion: Within the limits of the present study (first of all the small number of subjects), an experimentally induced jaw muscle pain, under controlled conditions, seems to affect the position but not the number of posterior occlusal contacts

Riabilitazione dell'arcata superiore con protesi parziale rimovibile e sistemi di ritenzione adesivi: un caso clinico.

Obiettivi: Presentare la riabilitazione per mezzo di una protesi combinata con attacchi adesivi di una paziente, portatrice di una protesi parziale rimovibile superiore, che desiderava una protesi più estetica. Materiali e metodi: Si è proceduto alla prepara- zione delle superfici palatali dei denti e alla presa dell’impronta. È stato realizzato uno splintag- gio fuso con attacchi che è stato poi reimpron- tato. Si sono registrati i rapporti intermascellari. Dopo la prova montaggio e l’impronta delle sel- le edentule, la protesi è stata finalizzata. Risultati e conclusioni: Il controllo a 16 mesi ha mostrato il successo della riabilitazione. L’impiego di attacchi adesivi come ritenzione di una protesi parziale rimovibile può essere un’opzione terapeutica in casi clinici in cui la riduzione dei costi biologici ed economici è di primaria importanza

Protesi totale

La protesi totale è una protesi rimovibile che sostituisce l’intera dentatura e le strutture associate del mascellare superiore o della mandibola. È una protesi a supporto esclusivamente mucoso. È costituita da un corpo protesico in resina acrilica rosa sul quale sono montati dei denti artificiali preformati in resina acrilica, resina composita o ceramica. Trova indicazione nei casi di edentulia totale

Use of monolithic lithium disilicate for implant abutment and crown: A clinical report

Background Lithium disilicate is usually used for producing prosthetic crowns to be cemented on teeth or implant abutments. On the contrary, its use for producing implant abutment is not reported. This report describes the use of monolithic lithium disilicate to realize implant abutment and crown. Case report A 60-year-old male patient required dental implant restoration for replacing the upper right central incisor. A lithium disilicate abutment and crown were realized by pressing. Conclusion Lithium disilicate may be a valid alternative to zirconia for producing implant abutments in the esthetic area