Preparation Of Abutment Teeth Research Articles

Assessment of the of fixed dental prosthesis impressions received at commercial dental laboratories in Aljabal-Alakhdar region, Libya0

Background: Crown and bridge prosthodontics needs an accurate and precise impression (positive replica) of the abutment teeth and the edentulous region to be rehabilitated for the dental technician to be able to construct the high quality and well adapted fixed dental restoration without mistakes. The aim of the current survey was to assess any visible mistakes commonly observed in fixed dental prosthesis impressions received at five commercial dental laboratories, frequency errors determination, and to determine any possible association between the preparation finish line errors and other assessed factors. Materials and methods: 150 fixed prosthodontic impressions were collected from five commercial dental laboratories located at Aljabal-Alakhdar region, Libya. All the fixed prosthodontic impressions which had been received by the visited commercial dental laboratories were assessed for many factors in relation to the accuracy such as the dental arch involved, prepared abutment teeth, dental impression materials used, and final techniques and viscosity of the impression, the type of impression tray, full-arch or segmental impression tray, the impression tray size, type of fixed dental restoration requested, mistakes in impression material or tray used, gingival tissue dilation errors, closed-mouth impression technique errors, and finish line errors. No attempts were made to determine the reason of the detected errors in each fixed prosthodontic impression assessed. Association between dental practitioner years of experience and gender and impression errors was evaluated. The association between categorical variables and the outcomes were examined by the use of Chi square and Fisher exact tests. Results: Condensation silicone was the most impression material used. Of the impressions evaluated 121(80.6%), 97% have at least one detectable error, 103(68.6%) had finish line errors, 53.9% had tooth preparation area errors. Visible contamination of impression with blood was seen in about 79(52.2%) of the assessed impressions. There was significant association between the type of dental impression material and errors in the preparation cervical finish line and tooth preparation area. Conclusion: In the present study, it has been found that a high frequency of recognizable errors was detected in crown and bridge impressions received by the five commercial dental laboratories. This can result in poorly fitted fixed restorations cemented for the fixed prosthodontic patients.

Feasibility of software-based assessment for automated evaluation of tooth preparation for dental crown by using a computational geometric algorithm

The purpose of this study was to propose the concept of software-based automated evaluation (SAE) of tooth preparation quality using computational geometric algorithms, and evaluate the feasibility of SAE in the assessment of abutment tooth preparation for single-unit anatomic contour crowns by comparing it with a human-based digitally assisted evaluation (DAE) by trained human evaluators. Thirty-five mandibular first molars were prepared for anatomical contour crown restoration by graduate students. Each prepared tooth was digitized and evaluated in terms of occlusal reduction and total occlusal convergence using SAE and DAE. Intra-rater agreement for the scores graded by the SAE and DAE and inter-rater agreement between the SAE and DAE were analyzed with the significance level (α) of 0.05. The evaluation using the SAE protocol demonstrated perfect intra-rater agreement, whereas the evaluation using the DAE protocol showed moderate-to-good intra-rater agreement. The evaluation values of the SAE and DAE protocols showed almost perfect inter-rater agreement. The SAE developed for tooth preparation evaluation can be used for dental education and clinical skill feedback. SAE may minimize possible errors in the conventional rating and provide more reliable and precise assessments than the human-based DAE.

ASSESSMENT OF ORTHOPEDIC TREATMENT LATE RESULTS OF PATIENTS WITH FIXED PARTIAL DENTURES DUE TO THE FUNCTIONAL STATE OF ABUTMENT TEETH

The scientific work highlights the results of an index assessment of the periodontal condition of patients abutment teeth with dentition defects which were replaced with metal-ceramic fixed partial dentures due to partial teeth loss. Since during the preparation of abutment teeth there is sometimes a need for endodontic treatment of them due to medical indications, we investigated the state of the periodontium before, during and after treatment and compared index indicators of pulpless teeth with teeth in which the vascular-nerve bundle was preserved. It was established that the periodontium of the vital tooth recovers and functions much better in comparison with the surrounding dental tissues of a nonvital tooth. Where there are inflammatory changes, which are objectively caused by pronounced swelling and bleeding of the gingival papilla. It is caused due to rubber dam pressure, which in turn is confirmed by reliable data of index indicators determined in various the terms of the treatment.
 After conducting a detailed examination of patients with vital abutment teeth with defects in the hard tissues of the teeth, we found that in the age group of 30-39 years, the most common defect in the hard tissues of the teeth was caries damage, which was observed in 8 patients (72.7%), damage due to injuries was found in 2 patients (18.2%), enamel hypoplasia was found in 2 patients (18.2%).
 Treatment of partial adentia involves the preparation of abutment teeth followed by the manufacture of fixed bridge prostheses. However, the vitality of the abutment tooth should be taken into account and the reserve forces of the periodontium should be taken into account in order to prevent functional overload. It is also necessary to monitor the hygienic condition of the oral cavity during the treatment and at various times after its completion.
 The peculiarity of the proposed method of preparation of vital upper and lower abutment teeth consists in the creation of a champfer on the vestibular surface with the transition to an imitation of a champfer on the oral surface, under constant control of the thickness of the peripulpal dentin using a dentometer with the use of full water cooling and subsequent fixation of provisional crowns. The use of a complex of diagnostic techniques for full control of the effectiveness of treatment during and after prosthetics at different times is substantiated and proposed.
 The gnathodynamometric study was carried out using an advanced device, the VIZIR E1000 gnathodynamometer: the plates placed between the opposing teeth were bitten, as a result of which the load was digitized using a flexible connection through an analog-digital converter and displayed on the display of a computer program, displayed graphically in newtons (N), the time of the masticatory load was also recorded in seconds.
 Using data from clinical indices, it was determined that the preservation of vital teeth is a reliable criterion of the effectiveness of the use of partial fixed prostheses than the use of pulpless teeth. The absence of periapical trauma in vital teeth, which occurs in pulpless teeth due to extirpation of the neurovascular bundle, is demonstrated by the Russel index, and other indices also demonstrate mucosal irritation caused by the use of rubber dams due to the need for quality endodontic treatment.

Evaluation of One- and Two-Step Impression Techniques and Vertical Marginal Misfit in Fixed Prothesis.

12 impressions were made of a resin maxillary model (second premolar and second molar) with two prepared abutment teeth using vinyl polysiloxane (VPS); the margin of the second premolar was 0.5 mm subgingivally; and the margin of the second molar tooth was at the level of the gingiva. Impressions were made using two techniques: one-step and two-step putty/light materials. A three-unit metal framework was fabricated on the master model using the computer-aided design/computer-aided manufacturing (CAD/CAM) technique. The vertical marginal misfit was evaluated in the buccal, lingual, and mesial and distal surfaces of the abutments on the gypsum casts using a light microscope. Data were analyzed using the independent t-test (α < 0.05). The results showed significantly lower vertical marginal misfit in all six areas evaluated around the two abutments in the two-step impression technique compared with the corresponding values in the one-step technique. Vertical marginal misfit in the two-step technique with a preliminary putty impression was significantly lower than in the one-step putty/light-body technique.

A novel chairside technique to assess the interocclusal clearance and abutment axial walls during tooth preparation.

The importance of a judicious and unerring abutment tooth preparation in the field of prosthodontics has always been paramount. It is not uncommon for many clinicians to face challenges during laboratory fabrication of fixed prostheses, caused due to inappropriate occlusal clearance and over axial wall taper of the abutment tooth. With evolving technologies and methods, the modus operandi for attaining such tooth preparation is varying; however, every technique has its own shortcomings. The technique mentioned in the article is cost-effective as it uses modified Heister mouth gag forceps to achieve the desired objective of evaluating the prepared abutment morphology three-dimensionally with minimum chairside time.

CAD/CAM technology for fabrication of reduction guide for RPD parallel guiding planes preparation: A dental technique.

The preparation of parallel axial wall guide planes in abutment teeth is essential for providing a correct path of insertion and removal axis for removable partial dentures (RPDs). With the introduction of digital resources, new alternatives to the conventional method can be used to manufacture guide preparation for guide planes. To describe the use of computer-aided design/computer-aided manufacturing (CAD/CAM) technology for the manufacture of guide planes to guide the reduction of the axial walls of abutment teeth according to the insertion and removal axis of the RPD. This technique used the "bite splint" module of the Dental Wings software for the virtual planning of guide planes, to promote the construction of axial walls parallel to the abutment teeth. This was performed from the virtual design on a standard tessellation language (STL) file obtained by intraoral scanning, which determined the best trajectory for insertion and removal of the metallic structure. Digital technology allows the design and production of guide planes for the preparation of abutment teeth, simplifying the conventionally used technique, with precision and speed.

Comparative characteristics of the physical and mechanical properties of the self-etchangeable self-adhesive composite cement for indirect restorations "Maxcem Elite TM"

Summary. The article deals with an actual problem of orthopedic dentistry: the choice of a reliable material for fixing indirect restorations by comparing the physical and mechanical properties of self-adhesive self-etching composite cements.&#x0D; The aim of the study – to carry out a comparative analysis of self-etching self-adhesive double-fixation cements for indirect restorations in terms of physical and mechanical properties.&#x0D; Materials and Methods. For comparison, in terms of physical and mechanical parameters, a self-etching self-adhesive composite cement for indirect restorations "Maxcem Elite", Kerr, California, USA was taken. "Maxcem Elite" refers to self-etching self-adhesive composite cements of double fixation, which has a number of positive qualities, such as high physical and mechanical properties, good aesthetic properties, radiopacity. We analyzed the following physical and mechanical parameters: the appearance of the paste, depth of hardening, mm, diametric strength, MPa, conical yield point according to Heppler, MPa, hardness according to Heppler, MPa, water absorption in 7 days, μg/mm3, water solubility in 7 days μg/mm3, adhesive strength, MPa, peel strength, MPa.&#x0D; Results and Discussion. According to the average test depth of hardening (mm) material "Maxcem Elite" is inferior to others: material Bifix QV by 14.9 % and Relyx U 100 by 13.3 %. This does not significantly affect the quality of the connection of the adhesive structure with the hard tissues of the tooth, especially due to the method we have developed for the preparation of abutment teeth in the manufacturing of adhesive pads. On the other hand, according to the average value of the index of diametrical strength (MPa), the studied material "Maxcem Elite" is by 17.2 % better than Bifix QV, and by 17.3 % better than Relyx U 100. Comparing these and other physical and mechanical properties of materials on average, one must bear in mind the random nature of these values. From the results of the study, it can be seen that the difference between the indicators of the Maxcem Elite material and analogues is confirmed at a very high level of significance. The study of the level of water absorption indicates the probable absence of variability of the indicator of the studied material in comparison with comparable analogs. The value of the water solubility index of all the composites under study practically does not differ from the value of "Maxcem Elite" (within (2.5±0.1) %), and corresponds to the requirements of ISO 4046.&#x0D; Conclusions. The research results show that the investigated composite material "Maxcem Elite" in the main parameters corresponds to analogs, in most of the indicators it combines their best characteristics. In it, the adhesive strength of the connection with the hard tissues of the tooth is noticeably enhanced and better peel strength makes it possible to profitably use this material "Maxcem Elite" for fixing the adhesive structures.

Characteristics of the Physical and Mechanical Properties of Self-Etching Self-Adhesive Cements for Indirect Restorations in a Comparative Aspect

The purpose of the study was to carry out a comparative analysis of self-etching self-adhesive double-fixation cements for indirect restorations in terms of physical and mechanical properties. Materials and methods. For comparison, in terms of physical and mechanical parameters, a self-etching self-adhesive composite cement for indirect restorations "Maxcem Elite", Kerr, California, USA was taken. "Maxcem Elite" refers to self-etching self-adhesive composite cements of double fixation, which has a number of positive qualities, such as high physical and mechanical properties, good aesthetic properties, radiopacity. We analyzed the following physical and mechanical parameters: the appearance of the paste, depth of hardening, mm, diametric strength, MPa, conical yield point according to Heppler, MPa, hardness according to Heppler, MPa, water absorption in 7 days, μg/mm3, water solubility in 7 days μg/mm3, adhesive strength, MPa, peel strength, MPa. Results and discussion. According to the average test depth of hardening (mm) material "Maxcem Elite" is inferior to others: material Bifix QV by 14.9% and Relyx U 100 by 13.3%. This does not significantly affect the quality of the connection of the adhesive structure with the hard tissues of the tooth, especially due to the method we have developed for the preparation of abutment teeth in the manufacturing of adhesive pads. On the other hand, according to the average value of the index of diametrical strength (MPa), the studied material "Maxcem Elite" is by 17.2% better than Bifix QV, and by 17.3% better than Relyx U 100. Comparing these and other physical and mechanical properties of materials on average, one must bear in mind the random nature of these values. From the results of the study, it can be seen that the difference between the indicators of the Maxcem Elite material and analogues is confirmed at a very high level of significance. The study of the level of water absorption indicates the probable absence of variability of the indicator of the studied material in comparison with comparable analogs. The value of the water solubility index of all the composites under study practically does not differ from the value of "Maxcem Elite" (within (2.5±0.1) %), and corresponds to the requirements of ISO 4046. Conclusion. The research results show that the investigated composite material "Maxcem Elite" in the main parameters corresponds to analogs, in most of the indicators it combines their best characteristics. In it, the adhesive strength of the connection with the hard tissues of the tooth is noticeably enhanced and better peel strength makes it possible to profitably use this material "Maxcem Elite" for fixing the adhesive structures

Investigation of stress distribution within an endodontically treated tooth restored with different restorations

Background/purposeRecently, metal-free restoration has become the standard in prosthetic treatment. However, it is still unclear which combination is most effective in preventing root fracture and secondary caries. The purpose of this study was to evaluate the influence of different post systems, crown materials, crown thickness and luting agents on the stress distribution around the crown margins, cervical dentin and the tip of the post.Materials and methodsNinety-six mandibular first premolar models were developed and analyzed using finite element analysis (FEA). Two designs of crowns, six kinds of crown materials, four types of post and core systems and two kinds of luting agents were included and evaluated for the stress distribution within the abutment teeth. The Von Mises stress magnitudes were compared among all models.ResultsThe stress at the tip of the post decreased as the young's modulus of luting agent decreased; The stress concentrated more at the cervical area (dentin and crown), as the physical properties of the crown material increased.ConclusionCrowns fabricated using polyetheretherketone (PEEK) can reduce the stress concentration at the cervical area, so it may be possible to reduce the amount of tooth reduction during abutment tooth preparation. The stress distribution around the post tip is affected by the post and core systems and luting agent, regardless of crown materials and thickness. When inserting a post of the higher Young's modulus such as zirconia post, methyl methacrylate luting cement can reduce the stress concentration at the tip of the post.

A novel tooth-supported removable bridge without preparation of abutment teeth − A case report −

A novel tooth-supported removable bridge without preparation of abutment teeth − A case report −

Effectiveness of local and topical anesthesia during gingival retraction

Objective: To compare the effectiveness of local and topical anesthesia during gingival retraction in preparedabutment teeth. Material and Methods: 72 patients desiring full mouth rehabilitation or bilateral fixed partialdenture in the same arch were selected based on the inclusion criteria framed and were randomly allocated intoGroups A and B of 36 each. Patients in Group A received gingival retraction with topical anesthesia and GroupB received gingival retraction with infiltration anesthesia. All the patients were tested for pain, discomfort andbleeding during gingival retraction. Results: There was no significant difference in pain, discomfort and gingivalbleeding (P &gt;.05) during gingival retraction using topical and local anesthetic agents. Conclusion: Topicalanesthesia was equally effective as infiltration anesthesia in managing the pain, discomfort and bleeding duringgingival retraction by cord packing in prepared abutment teeth. KEYWORDSGingival retraction techniques; Topical administration; Infiltration; Pain.

62 - Compression Force Testing of Veneer-Retained Anterior Fixed Partial Dentures

The focus of this study is twofold; the first objective is to evaluate the resistance of veneer-retained anterior fixed partial dentures to compression testing. The second objective is to determine if veneer retainers with these axial grip extensions improve the restorations resistance to compressive forces as demand for biomaterial and access to care is often globally differentiated. Two maxillary typodont models with edentulous spaces in the left lateral incisor area were obtained. On each typodont model, the central incisor and canine neighbouring the edentulous space were given veneer-type preparations with a chamfer finish line. On one model, 2-mm axial grip extensions were added to the prepared facial surface of the abutment teeth. Metal duplicates of the prepared abutment teeth and edentulous spaces of each typodont model were produced using the lost wax casting technique. The two metal duplicates were scanned, and ten identical CAD/CAM restorations were produced for each metal duplicate. The restorations were cemented to metal duplicates and were subjected to compressive strength testing using a universal testing machine. Compressive forces were applied from the incisal margin towards the cervical in order to determine the force at which the restorations undergo debonding or fracture. Subject specimen N tested totalled 20. The veneer-retained restorations without axial grip extensions all underwent debonding but none fractured. In the veneer-retained restorations with axial grip extensions retention, nine cases of debonding (90%) were recorded and one case of fracture (10%) was recorded. The veneer-retained restorations with axial grip extensions (M = 302 N, SD = 79) compared to the restorations without axial grip extensions (M = 228 N, SD = 60) withstood significantly higher compressive forces (p < 0.05). This study shows that veneer-retained anterior fixed partial dentures with axial grip extensions can withstand higher compression forces than veneer-retained anterior fixed partial dentures without axial grip extensions. Veneer-retained anterior bridges can be useful in addressing esthetic concerns in a minimally invasive manner. This study shows that axial grip extensions can play a crucial and important role in addressing concerns about resistance and long-term success of this type of restoration. An important clinical relevance will be highlighted for endodontically treated dentition versus non-endodontic treated dentition. Additionally, there will be reporting on intersectional pending studies regarding custom geo-position of axial grip extensions preparation design.

A Digital Chairside Technique for an Accurate Evaluation of the Taper of the Prepared Teeth for the Restoration of Crowns and Fixed Partial Dentures

The aim of the article was to provide a digital chairside method for the objective evaluation of the taper of prepared abutment teeth retaining a fixed partial denture (FPD). According to research, the taper of the abutment teeth supporting an FPD has a direct effect on both retention and stress transmission to the abutment teeth. However, no approaches have been documented in the literature that objectively quantify the taper of the prepared teeth chairside, in a simple and cost-effective manner. The proposed technique utilized an intraoral camera with an on-the-go (OTG) connection, and a silicone dental bite block. The images of the prepared teeth were captured using this camera from the facial aspect. An indigenous program was developed using the MATLAB (Matrix Laboratory 2013) software for the analysis of the images and the taper of each abutment tooth was calculated in degrees using the software. The novel, chairside, digital technique utilizes an intraoral camera and a computer-generated software package to quantify and evaluate the taper of abutment teeth efficiently. This, in turn, can help minimize the errors in the treatment of FPD and improve the retention of the prosthesis. The current technique enables the clinician to avoid over-preparation of the abutment teeth by assessing its taper chairside. This digital technique can be a beneficial alternative to the existing procedures for an accurate assessment of taper, especially for the inexperienced operator. Hence, the quality of retention, and thereby the long-term success of the crowns and FPDs, can be enhanced. This article was presented as a postgraduate paper titled "Scan and Plan" on March 6, 2020, at 22nd IPS (Indian Prosthodontic Society) PG Convention, Kochi, India.

Method of preparation "along the axis" of teeth that serve as a support for extended orthopedic structures

A common mistake of an orthopedic dentist when carrying out odontopreparation of teeth is nonobservance of the parameters of the permissible convergence of the axial walls of the teeth [1]. Analysis of the literature allows us to conclude that with the taper of the tooth walls at 15 degrees, the retention of the crowns is 70 % [2]. The aim of this work was the development of an improved method for coaxial odontopreparation of teeth. This article describes the method of odontopedication of teeth, which are a support for fixed orthopedic structures of an extended nature. The essence of the method is to create a bed on the abutment teeth using a thin fissure bur. The process of coaxial preparation of abutment teeth in the author's technique consists of several stages, which makes it possible to control the preparation accuracy and qualitatively reduce the likelihood of excessive grinding of tooth tissues.

Адгезивный фотокомпозитный зубной протез – вариант восстановления дефекта зубного ряда во фронтальных участках (описание клинического случая)

Summary. Having and maintaining a smile aesthetic is an essential component of modern popular culture. Adhesive bridges («Maryland bridge») have been developed to eliminate single included defects in the dentition in the frontal areas, without preparing the supporting teeth. In modern conditions this technology is the method of choice since single defects in the anterior part of the dentition can also be eliminated through orthodontic treatment, manufacturing of a partially removable plate prosthesis, a traditional dental bridges, the manufacturing of cantilever orthopedic structures and prosthetics based on a dental implant. Adhesive dentures are a relatively new dental technology (which is on the border of orthopedic and therapeutic dentistry) the first work in this direction was carried out in the early 80s of the twentieth century. Modern adhesive bridges are divided into two large groups – solid metal and photopolymer (composite) which prevail in practice. The optimal form of the release of the reinforcing element which combines a slight preparation of abutment teeth to a safe depth, high physical and mechanical properties, simple achievement of the anatomical shape of the teeth in the bridge structures of the anterior and posterior teeth is fiberglass in the form of ribbons 2 mm wide, up to 0.5 mm (this is the most effective width and thickness for clinical practice) and braided type. Using adhesive bridges, it is possible to optimally restore the aesthetics of the anterior part of the dentition in one visit without preliminary preparation of adjacent teeth. An example of the manufacture of a photocomposite adhesive prosthesis reinforced with glass fiber for the restoration of a single included defect in the dentition in the frontal area using domestically produced materials is given. Key words: teeth, defect, composite, adhesion, fiberglass.

Использование адгезивных волоконных систем для восстановления дефектов зубных рядов

Summary. The article deals with the use of adhesive fiber systems for the restoration of dentition defects. Adhesive bridges made in a direct way in one patient visit allow for the restoration of single included defects in the dentition with minimal preparation of abutment teeth. Key words: included dentition defects, adhesive bridges, fiber reinforcement elements; composite materials.

THERMOGRAPHY OF PERIODONTAL TISSUES DURING DIATHERMOCOAGULATION RETRACTION

Gingival retraction at the preparatory stage of orthopedic teeth restoration with fixed dental appliances is a common procedure in daily dental practice, the success of which will depend on the effectiveness of orthopedic treatment in general. Given certain shortcomings of well-known mechanical and mechano-chemical retraction techniques, the consequences of which may lead to unpredictable aesthetic results, the purpose of this work was to study changes in temperature of marginal gums around teeth at different stages of their orthopedic restoration by fixed metal-ceramic structures based on the thermography findings. The study included 54 patients aged 20 to 60 years, with partial or complete destruction of the coronal part, among whom there were 29 people (53.7%) who underwent gum retraction by diathermocoagulation, and 25 people (46.3%) who underwent retraction of the gingival groove with cotton threads "Ultrapak" (“Ultradent", USA). Measurements were performed prior the operation, during it, in 60 minutes after the completion of diathermocoagulation, and in 7 days after fixation of the cermet crown (14 days after retraction). The thermographic study showed that immediately after the procedure of diathermocoagulation retraction, the temperature of the marginal mucosa went up from 27.3° C (St.Err. 0.28) to 60.2° C (St.Err. 0.72) in the group 1, while in group 2 after mechanochemical retraction there was an increase in temperature from 27.3° C (St.Err. 0.30) to 28.9° C (St.Err. 0.3). 60 minutes after the end of the retraction, the average thermographic index in the group 1 was 28° C (St.Err. 0.28), while in group 2 it equalled to 28.1° C (St.Err.0.31). Control thermography on the 14th day after gum retraction showed a slight decrease to 27.1° C (St.Err. 0.29) in the group 1, and 26.72° C (St.Err. 0.29) in the group 2. The use of diathermocoagulation method of preparation (retraction) of abutment teeth in case of partial or complete destruction of their coronal part improves the quality of orthopedic treatment of patients by using metal-ceramic constructions of dentures. Analysis of thermodynamics in dental and periodontal tissues using the latest thermographic devices with subsequent computer processing of information obtained is of great prospects for further in-depth research.

Current status and perspective of CAD/CAM-produced resin composite crowns: a review of clinical effectiveness.

The purpose of the present review was to survey the available literature on computer-aided design/computer-aided manufacturing (CAD/CAM)-produced resin composite materials to provide clinicians with a current overview of the key components necessary for daily clinical use. An electronic search was conducted in the PubMed database. Peer-reviewed articles in English language on the use of resin composites in CAD/CAM dental crowns were included. A total of 122 full-text articles were identified, 15 of which were selected during the initial review. Two additional articles were also discovered through a manual search, to obtain a final total of 17 articles included in the present review. Of these, 16 were to in vitro studies, and one was an in vivo study. Findings from the in vitro studies indicate that resin composite block materials for CAD/CAM applications demonstrate excellent physical properties and are appropriate for the clinical restoration of premolars and molars. However, the in vivo study reported a low 3-year success rate, but high survival rate for resin composite CAD/CAM crowns placed in the premolar region. The key to ensuring the successful prognosis of a resin composite CAD/CAM crown is to ensure that all steps—such as proper case selection, abutment tooth preparation, occlusal adjustment, and bonding—are accurately performed.

Aesthetic rehabilitation in a patient with skeletal mandibular deficiency and open bite: journey from splinted metalloceramic prosthesis to all-ceramic crowns

This case report is of a 31-year-old female who presented with splinted and faulty metalloceramic prosthesis on maxillary anterior teeth, which was responsible for localised periodontal disease and poor aesthetics. At multiple sites the ceramic had chipped off and the prosthesis colour did not match with the adjacent healthy teeth. A multidisciplinary approach of endodontics, periodontics and prosthodontics was employed for this case. The treatment plan consisted of removing the faulty prosthesis, endodontic retreatment of inadequately root-treated teeth and endodontics in the other coronally prepared abutment teeth. Crown lengthening surgery was performed for the correction of periodontal pockets and high smile line and maintenance of an adequate biological width. After periodontal healing, all-ceramic individual crowns were placed on the maxillary anterior teeth along with a three-unit all-ceramic bridge for the replacement of the left upper maxillary first premolar. The final results were aesthetically pleasing with good marginal fit. The patient was extremely satisfied with the outcome as all her concerns were addressed. It is, therefore, advisable to consider placing individual crowns rather than multiunit splinted prosthesis whenever possible.

Evaluation of Abutment Parallelism and Path of Withdrawal Using Three Intra- and One Extra-Oral Methods: A Survey and In vitro Study

Abstract Purpose: The purpose of this study is to evaluate four different methods used to examine preparation taper and relative parallelism of the prepared abutment teeth. Materials and Methods: A total of 12 artificial teeth were prepared simulating six sets of prepared abutments. Proximal walls of the premolars in all sets were prepared parallel and 90° to the occlusal plane, whereas walls of the second molars were prepared either 0°, 20°, or 45° to the long axis of the premolar preparation. A total number of 210 participants were involved in the study. All data of the taper evaluation and responses to the questionnaire were coded and entered into an Excel Spreadsheet file. Statistical analyses of the participants' responses were performed using the Chi-square test with P &lt; 0.05 was considered statistically significant. Results: No significant difference was found between the educational levels relative to their responses to level of difficulty, sensitivity, skills, and technical demands for the four techniques. The intraoral mirror technique in the mandibular arch was found to be statistically significantly (P &lt; 0.05) better. The surveyor technique in the maxillary arch was found to be statistically significantly (P &lt; 0.05) better. The highest percentage of faculty members (50%) chose dental surveyor (DS) as the most preferred technique to be included into the academic curriculum. Conclusions: The DS was more favored among the respondents across all educational levels. This technique presented high potential in accurately evaluating tooth preparation in comparison to the intraoral techniques.