Prosthodontics

The management of the interim phase of a complete oral rehabilitation in patients with severely worn dentition is often challenging due to loss of occlusal vertical dimension, loss of tooth structure, uneven wear of teeth creating an uneven plane of occlusion, and para-functional habits. This paper will demonstrate how a clear thermo-forming matrix fabricated from the diagnostic wax-up can be used as a guide to facilitate treatment.

A maxillary midline diastema (MMD) is a common form of incomplete occlusion and often is a primary complaint of patients during dental consultations. MMD is considered to be a multifactorial phenomenon and can therefore be best restored with a multidisciplinary approach. This clinical report presents a multidisciplinary approach to the management of a 4.0-mm MMD by using limited orthodontics combined with periodontal and prosthodontic treatments.

Edentulousness is one of the human disabilities. Dental implants have increased the quality of life as it restores both function and
aesthetics. Due to anatomic challenges, implants can be placed with inclinations and angled abutments can be used. This articles presents a
case report of management of mandibular anterior missing tooth with the placement of angled implant using custom abutment along with
screw retained prosthesis.

This study investigated changes in oral health-related quality of life (OHRQoL) in partially edentulous patients treated with removable dental prostheses (RDPs), fixed dental prostheses (FDPs), fixed-removable (combined) restorations (COMBs), and implant-supported fixed prostheses (ISFPs). A total of 200 patients (30 to 50 years old) were enrolled: 45 received RDPs, 32 received FDPs, 66 received COMBs, and 57 received ISFPs. OHRQoL was measured using the shortened version of the Oral Health Impact Profile (OHIP-14) before treatment and 6 weeks and 6 months after treatment. Treatment groups were sex-neutral; however, significant differences were found relative to age and Kennedy classification. A general linear model was used to explore the interaction of age and Kennedy classification with treatment modality. Pretreatment analysis revealed that the psychologic discomfort domain showed the greatest negative impact on OHRQoL, while functional limitation had the smallest effect. Within...

Purpose: The aim of this study was to determine effect of compressive cyclic loading on fatigue resistance and microleakage of monolithic CAD/CAM molar ceramic and composite crowns. Materials and Methods: Thirty-two extracted molars were prepared to receive ...

Patient: A 61-year-old man with full thickness facial cheek defect due to a complication of tissue necrosis occured after surgicaland followed radiation therapy for basal cell carcinoma of the submental region required prosthetic rehabilitation. Apartfrom the aesthetic concern, he was suffering from other oral debilities such as difficulty in eating, speaking and swallowing. As this type of carcinoma may have a potential risk of morbidity and mortality, it is an obligation of a prosthodontist to treat the patient to have an acceptable and normal social life for his remaining lifespan. The defect was, therefore, prosthetically rehabilitated with a double-layered technique of maxillofacial prosthesis which simulated both intra- and extra-oral tissues. Cosmesil Silicone was used to prepare the epithesis extraorally. The prosthesis was then soft relined using DentuSil Silicone.. The connection of both materials was made with an arcrylic element in the mold.

Discussion: This resulted in practically good durability, placement, retention and adaptation of the denture both extraorallyand intraorally. The patient reported being satisfied with the function and aesthetics of the epithesis.

Conclusion: This simple alternative approach of a double layered techique may help to improve the aesthetic and functionin the reconstructions of patients with facial full thickness cheek defects.

The purpose of this study was to compare the retention of circlet (E) clasps and back-action clasps against three abutment surface materials during long-term simulation of attachment and detachment. Forty-eight test models were constructed by placing premolars (natural abutments or metal dies) inside metal blocks to test different abutment retention surface materials (sound enamel, composite resin, and glass-ceramic; 16 each). The models were duplicated into investment models for construction of circlet (E) and back-action clasps. Removal and insertion cycling of clasps was carried out for 250, 500, 1000, 2000, 4000, 8000, and 16,000 cycles. The retention of each clasp was measured before cycling and after each interval. Data were analyzed using 1-way-ANOVA, 2-way-ANOVA, and Mann-Whitney U tests. No significant differences in retention of either clasp were found between the three abutment material surfaces; however, there was a significant decrease in retention force of the circlet (E) clasp between 1000 and 2000 cycles but not of the back-action clasp. (1) The back-action clasp maintains its retention force for a longer period than the circlet (E) clasp. (2) Composite resin contouring of teeth provided retention comparable to enamel and a ceramic material.

Studies on the oral health status of institutionalized older adults are less prevalent than those of community-dwelling older adults, as institutionalized older adults tend to be frailer. Poor oral health in older adults has a negative impact on the quality of life and self-confidence of older people and potentially poses a financial burden on both the older adult and society in general. The objective of this study was to assess and compare the oral health status of state institutionalized older adults in Malta with that of their European counterparts. A total of 278 older adults with an average age of 83.6 ± 6.5 years from nine state institutions in Malta were randomly selected. Participants were clinically examined for caries, periodontal disease, oral mucosal lesions, and prosthetic status. The oral health status of state institutionalized older adults was poor, with a very low routine dental attendance (29.3%) and, consequently, a high level of treatment need (44.4% of dentate i...

Statement of the problem: On a pressed lithium disilicate restoration, the building up of a wax pattern of the future restoration is a necessary step on the fabrication process. Conventionally, a wax pattern can be produced by handmade or milled procedures; however , the development of additive manufacturing technologies allows a new fabrication method. Purpose: The present study measured the marginal and internal gap of handmade, milled and additive manufactured patterns for an onlay restoration. Material and methods: A preparation of an onlay restoration was made on an extracted mandibular tooth. A definitive cast was fabricated from a conventional silicone impression of the prepared tooth. Three groups were established: handmade (HM), milled (ML) and additive manufactured (AM); 4 specimens per group were obtained. The marginal and internal gap of each pattern was measured on the extracted molar through a computed tomography test. Sixty measurements were done to measure the marginal gap and another 60 measurements were calculated to analyze the internal gap on each pattern on the prepared tooth. A total of 1.440 measurements were completed. Mann-Whitney and Turkey statistical tests were used for pairwise comparison. Results: The mean of the marginal and internal gap was of 67.56 ± 6.08 μm and 80.62 ± 3.26 μm for the HM group, 85.28 ± 2.17 μm and 96 ± 1.97 μm for the ML group and 86.49 ± 1.74 μm and 91.86 ± 2.88 μm for the AM group, respectively. The HM group presented significantly lower marginal (p=0.029) and internal (p=0.029) gap compared to the ML and AM groups. There was no statistical significant difference (p=0.486) on the marginal gap between the ML and the AM groups, but the AM group, showed significantly (p=0.029) smaller internal gap than the ML group. Conclusions: All the groups presented less than 100 μm marginal and internal gap, which is considered clinically acceptable. Clinical implications: The three fabrication processes are viable options for manufacturing patterns for lithium disilicate onlay restorations, but the best marginal and internal fit was still obtained by the conventional handmade procedures.

The digital workflow - from the intraoral scanning, through the CAD design of the facially generated diagnostic digital wax-up, to the CAD-designed and 3D-printed silicone index with the diagnostic mock-up - provides a new approach that avoids the conventional manufacturing of casts. The development of the process requires a synchronized workflow and good communication between the dental technician, prosthodontist, and patient. This report describes a protocol for the diagnostic digital sequence for the treatment planning of an esthetic rehabilitation.

All-ceramic crowns are subject to fracture during function, especially in the posterior area. The use of yttrium-stabilized zirconium-oxide ceramic as a substructure for all-ceramic crowns to improve fracture resistance is unproven. The aim of this study was to compare fracture strength and fatigue resistance of new zirconium-oxide and feldspathic all-ceramic crowns made with computer-aided design/computer-aided manufacturing (CAD/CAM). An ivorine molar was prepared to receive an all-ceramic crown. Using epoxy resin, 40 replication dies were made of the prepared tooth. Twenty feldspathic all-ceramic crowns (Vita Mark II) (VMII) and 20 zirconium-oxide crown copings (In-Ceram YZ) (YZ) were made using CAD/CAM technique (CEREC-3D). The YZ copings were sintered and veneered manually with a fine-particle ceramic (VM9). All crowns were cemented to their respective dies using resin cement (Panavia F 2.0). Ten crowns in each group were subjected to compressive fatigue loading in a universal testing machine (instron). The other ten crowns from each group were loaded to fracture at a crosshead speed of 1 mm/min. Data were statistically analyzed using independent t-test and Fisher's exact test at alpha= 0.05. There was a significant difference between the survival rates of the two materials during the fatigue test (p < 0.001). All VMII crowns survived without any crack formation, while all YZ crowns fractured (40%) or developed cracks (60%). All the YZ crown fractures occurred within the veneering layer during the fatigue test. There was no significant difference in mean fracture load between the two materials (p= 0.268). Mean fracture loads (standard deviation) in N were: 1459 (492) for YZ crowns and 1272 (109) for VMII crowns. The performance of VMII crowns was superior to YZ crowns in the fatigue test. The premature fractures and cracks of the YZ crowns were attributed to weakness in the YZ veneer layer or in the core/veneer bond.

In edentulous individuals, flabby ridges are prevalent. In these individuals, insufficient retention and stability of a full denture are common issues. Because of its flexible tissue treatment option in such circumstances. The adoption of a liquid-supported denture in an individual with a totally edentulous maxillary arch with flabby tissue in the anterior area opposing a completely edentulous area, a liquid supported denture allows for improved stress transmission and thus gives an alternative mandibular arch is described in this case report. Esthetics were also enhanced by customising the dentures to fit the patient's lip colour.

This study assessed masticatory efficiency and duration of the masticatory cycle in 14 asymptomatic patients with severe bone resorption. All patients had worn complete dentures for over 10 years. Recall visits were scheduled at 5 months and 1 year after receiving new dentures. Fourteen patients were evaluated in this study. The Research Diagnostic Criteria questionnaire and tests of the efficiency and duration of the masticatory cycle were performed with artificial food before, 5 months after, and 1 year after new dentures were delivered. Masticatory efficiency was assessed using a sieve system; artificial food was ground for 35 masticatory cycles and monitored by the operator. Masticatory efficiency at 5 months was significantly improved for the 0.42-mm mesh. An improvement in masticatory efficiency and a reduction in mastication time were observed with the new dentures after 1 year. The results of this study indicated that 5 months did not allow enough time to demonstrate improved muscular capacity and ability after receiving new dentures. After 1 year, the duration of the masticatory cycle was reduced, and masticatory efficiency was significantly improved.

Aim: To evaluate the influence of three lighting conditions on the accuracy of tooth shade
matching.
Materials and methods: Ten prosthodontists participated in this study after being tested for
color deficiency using Ishahara’s tests. Ten patients were selected for shade matching procedure.
Shade of tooth 11 were taken under three lighting conditions (incandescent light, fluorescent light
and hand-held full spectrum light). Using spectrophotometer (Easy Shade ,VITA Zahnfabrik H,
Germany), shade of tooth 11 was recorded as control. Delta E was calculated for each reading
according to the CIE L*a*b* formula, between visually and digitally recorded shades.
Results: The percent of correct color matching choices with Incandescent light scored the
highest number of correct color matching (15), followed by hand-held full spectrum light (7)
then fluorescent light (6). Kruskal-Wallis test revealed significant differences in shade matching
under the three light sources (P Value = 0.0006). One-way ANOVA revealed significant difference
between fluorescent light and incandescent light (P Value= 0.039) while no significant difference
was found among other groups.
Conclusion: Different lighting conditions affect color-matching procedure. Hand-held full
spectrum light did not improve shade-matching procedure. Incandescent light showed better
lighting condition than both fluorescent light and Hand-held full spectrum light.
KEYWORDS: Shade matching, Light source, Shade guide, incandescent light, fluorescent
light, hand-held full spectrum light, digital shade analysis, spectrophotometer.

By the time, dental CAD/CAM technology achieved the significant and reliable success, which is adapting more in-depth and more in variety of dental industry demands, for both clinical professionals and dental laboratory experts, or dental and stomatology restoration technology in general. Obviously, those positive results had experienced by a lot of developing test and improvement, seeded and cultivated by not only the close and mutual collaboration of dental professionals, dental laboratory experts and engineering experts but also the adaption feedback from the end-users, known as our patients. The past is not only the foundation of the current achievements but also the way to the future dream. This general timeline panorama of the dental CAD/CAM technology development of global dentistry shows up an overview of the impact of a dental digital revolution in these recent days.

The identification of different dental implants and restorative components is difficult when dental records do not include an inventory of implant components. An implant record form is described. The form should be filled out and retained in the patient's chart for future use and implant maintenance visits.

We are blessed with a dynamic masticatory system
which allows us to function and exist. It is a highly
intricate unit and primarily related to chewing, speech
and swallowing. The ever so delicate balance between
the various components of the system is monitored by
the neuromuscular control.(1) Maxillo-mandibular
relationships establishment has got the attention of
prosthodontists ever since the dynamic and static
positions of the condyles in the glenoid fossa were
interpreted and understood. In an edentulous patient,
the teeth along with periodontal nerves are lost.

Ceramists may be able to produce excellent results, but none can improve on natural dentition. Natural teeth are always the benchmark to which every ceramist should aspire.
To become a better ceramist requires training and application, and one of the best ways of training is to copy natural dentition. The amount of information that can be gained just by examining natural teeth is enormous. Natural dentition is irregular, but it is also in proportion and perfectly balanced.
By trying to reproduce natural teeth,
the ceramist will appreciate their diversity,
and will never stop learning from the experience.
This article presents one way of
training to better understand the shape,
color, and materials of teeth.

Dental students in programs around the world typically pass preclinical courses before entering the clinic and working on actual patients. Since fixed prosthodontics is a preclinical course that requires a great deal of effort, students may experience a substantial amount of stress that may affect their self-confidence and/or clinical performance. In this study, an instructional video CD (VCD) and study guide depicting the step-by-step procedures involved in a metal-ceramic tooth preparation and provisional crown fabrication was prepared. Students at the Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, were divided randomly into two groups. Group A students trained as usual with live patients, and Group B students were given a copy of the VCD and study guide following a lecture. The students in Group B were encouraged to read the study guide and watch the VCD after live demonstrations. Then, both groups practiced individually on mannequins. At the end of th...

Purpose: To study luminescence, reflectance, and color stability of dental composites and ceramics. Materials and Methods: IPS e.max, IPS Classic, Gradia, and Sinfony materials were tested, both unpolished (as-cast) and polished specimens. Coffee, tea, red wine, and distilled water (control) were used as staining drinks. Disk-shaped specimens were soaked in the staining drinks for up to 5 days. Color was measured by a colorimeter. Fluorescence was recorded using a spectrofluorometer, in the front-face geometry. Time-resolved fluorescence spectra were recorded using a laser nanosecond spectrofluorometer. Results: The exposure of the examined dental materials to staining drinks caused changes in color of the composites and ceramics, with the polished specimens exhibiting significantly lower color changes as compared to unpolished specimens. Composites exhibited lower color stability as compared to ceramic materials. Water also caused perceptible color changes in most materials. The ma...

Purpose: The aim of the present study was to evaluate the stress distribution of three different support designs for mandibular distal extension removable partial denture (DERPD) associated with a pier abutment (lower second premolar) by 2-dimensional finite element analysis (2DFEA). Material and methods: A 2DFEA method (Patran 2011 program) was used to design three different models of Kennedy Class-I mod.2 (DERPD) with pier abutment (lower second premolar). Model A (M A) represented a conventional DERPD with I-bare clasp on the canine and long mesio-occlusal rest on the pier abutment. Model B (M B) represented a removable partial overdenture with a dome shaped preparation on the pier abutment. Model C (M C) represented a 3-unit metallic fixed partial denture using the 2 nd premolar and the canine as abutments, a conventional DERPD with I-bare clasp and mesial occlusal rest on the 2 nd premolar was made. A 50-N static vertical occlusal load was applied on cusp tips of canine, pier abutment and artificial teeth to calculate the stress distributions. Results: The analysis of the von Mises stress revealed that the stress concentration was located at the loaded areas for all models. Less stress values were recorded using the overdenture design in area related to the pier abutment. Conclusion: The results of stress analysis were insignificant for all designs in all studied locations and the maximum stress concentration at the pier abutment was slightly decreased by the use of a removable partial overdenture design. KEY WORDS: Stress analysis, Pier abutment, Removable partial denture, Finite element analysis. (2) Ahmed B. El-Okl, et al.

Objective: An analogue and digital workflow for the fabrication of a diagnostic 3D printed polymer template and its duplication for long-term injected composite resin interim restorations is described, because of the lack of scientific evidence in 3-dimensional (3D) printing applied to dentistry in terms of printer technology, printer parameters, postpolymerization processes, and material characteristics. In addition, in the case of 3D printed temporary resins, they cannot be relined successfully and its mechanical properties in the mouth have not been tested yet. Conclusions: The main benefits of this approach relate to the improvement of clinical and laboratory procedures, as conventional waxing is eliminated, conventional master casts are not needed and the process is entirely automatized, improving the workflow, with minimal intervention of the laboratory technician. Clinical Significance: The additive manufactured diagnostic template represents the materializa-tion of the digital diagnostic waxing and provides a powerful tool to visualize the digital diagnostic waxing in the patient's mouth and face. Furthermore, the diagnostic 3D printed template can be used for multiple applications including interim restorations, radiographical, or surgical guide fabrication. The duplication technique described provides a predictable workflow to obtain long-term injected resin composite restorations from an additive manufactured esthetic diagnostic template, improving the laboratory and chairside procedures.

Purpose: The purpose of this study was to compare the visual and colorimetric color stability of two ultra low-fusing and three conventional low-fusing porcelains on both glazed and polished surfaces.Materials and Methods: Twelve disks, 10 mm in diameter and 3 mm in thickness, were fabricated for each porcelain. Specimens were glazed using their specific glaze materials. For each type of porcelain, the specimens were divided into two groups: one group was immersed in methylene blue and the other group in distilled water as a control. The surfaces were visually examined for staining without magnification. Objective color measurement was performed for each sample using a Tristimulus colorimeter. After examining the color of the glazed specimens, glazed layers were removed from the surface of the specimens to simulate an intraoral environment. Then, porcelain polishing points and diamond polishing paste were applied. The samples were immersed again in methylene blue and distilled water, and after removing from the staining solution and distilled water, visual and objective measurements were performed again.Results: Visually discernible stain was present on the polished groups of all five porcelains immersed in methylene blue, whereas the glazed group immersed in methylene blue showed no staining. No staining was observed with glazed and polished samples immersed in distilled water. The objective evaluation showed that the polished porcelain surface of all five porcelain products had statistically significant color deviation than the glazed surface in the same group after immersion in methylene blue. The results of this study show a statistically significant difference in color stability between the polished and glazed specimens.Conclusion: It may be concluded that the glazed specimens showed a better color stability, although the staining observed in the polished specimens was not clinically noticeable.

One of the most important factors that determines the success of a maxillofacial prosthesis is retention. The struggle to achieve adequate retention has reduced as retentive measures have evolved over a period of time. Increased retention provides comfort and confidence to the patient to go out in social settings. The journey from using metal bands to using adhesives to placing implants for retaining a maxillofacial prosthesis has been fascinating and satisfying to many, but, the aim of achieving the full potential still remains incomplete.

Acrylics are compounds polymerized from monomers of acrylic, metacrylic acid or acrylonitrates. The purpose of this paper is to present the technology and use of acrylics for provisional dentine protection in the practice of dental prosthodontics. For this reason, we followed 120 clinical cases from the everyday clinical practice, divided into 4 groups of 30 patients who needed prosthetic reconstruction. The first group included cases in which we applied celluloid crowns for dentine protection, for the second group we used acrylic teeth from a set of teeth for complete dentures; in the third and fourth groups the fabrication was done with the system of an impression matrix and the acrylic resin block technique respectively. In all the examined patients, the gingival index by Silness and Loe and the vitality of the dental pulp were verified clinically, after preparation and 8 days from the placement of the provisional crown. The value for dental sensitivity measured after preparation...

The use of the removable partial denture to restore the posterior edentulous space continues to be a viable treatment option for patients who are not candidates for cantilever fixed prosthesis or dental implants because of the nature of the remaining teeth and bony support, the anatomy of the residual ridges, or financial constraints. The construction of removable partial denture is a delicate procedure since the prosthesis is supported by two different tissues namely teeth and mucosa. The different resiliency of these supporting tissues may lead to instability of the prosthesis. This article reviews various impression techniques that aim to equalize the masticatory load between teeth and edentulous areas thus enhancing the stability of partial denture during function and preserving the residual oral structures.