Comprehensive review of guidelines to practice prosthodontic and implant procedures during COVID-19 pandemic.

OBJECTIVES: To present a comprehensive review of current literature available on Corona virus disease and dentistry, modifications required in dental and laboratory settings; and recommended disinfection protocols in current scenario. Special emphasis has been given to discuss guidelines for handling different prosthodontic procedures and implications of this pandemic on prosthodontic practice, education and research. MATERIALS AND METHODS: Relevant literature pertaining to COVID-19 and dentistry was scrutinized on electronic search engines including PubMed, EMBASE and Cochrane. Guidelines given by various organizations, institutions, national and international regulatory bodies and Indian Prosthodontic Society were also consulted to gather information pertaining to the objectives of our review. RESULTS: and observations: A total of 160 articles including cross-sectional studies, in vitro study, narrative reviews, letters to the editor and opinions were found to be relevant in accordance with our search strategy. Documented literature revealed that Covid-19 pandemic has culminated in serious clinical, financial and psychological implications in the field of dentistry. Certain steps such as adoption of teledentistry, judicious use of protective equipment, use of rubber dams, pre-procedural rinses have been suggested unanimously. However, there is a dearth of evidence-based recommendations in literature. Data regarding consequences of delaying prosthodontic procedures and patients' perspectives is also sparse. CONCLUSION: The COVID-19 necessitates the need to adopt a balanced approach while treating patients and safeguarding the dental professionals at the same time. Risk-benefit ratio has to be assessed along with stringent following of guidelines and disinfection protocols to combat this unprecedented situation.

An in vitro comparative evaluation between virtually planned implant positions on interactive implant software versus actual implant positions achieved using sterolithographic open guide system.

PURPOSE: To evaluate and compare the positional and angular accuracy of virtual implant positions planned on cone-beam computed tomography and final implant positions achieved using a universal open guide system. MATERIALS AND METHODS: A dual scan of a partially edentulous jaw model along with prosthesis was done, and virtual implant planning was performed. Three implant positions in relation to 35, 36, and 37 were simulated (Group A). In total, 24 implants were placed in eight replaceable bone blocks (Group B) in the same region on the model using an open stereolithographic template. The linear positions and angulation of the placed implants were determined using Vision Measuring Machine. Deviations between virtually planned and surgically placed implants were analyzed in terms of linear and angular measurements. Data were analyzed with the independent-sample t-test with differences P ≤ 0.05 being considered statistically significant. RESULTS: The linear distance (mean ± standard deviation [SD]) in mesiodistal direction between implants in relation to 35 and 36, 36 and 37, 35 and 37 in Group A was 8.79 ± 0 mm, 8.71 ± 0 mm, and 17.50 ± 0 mm, respectively, and in Group B was 7.70 ± 0.58 mm, 8.11 ± 0.30 mm, and 15.80 ± 0.48 mm. All these above values were found to be statistically significant (P ≤ 0.05). The linear distance (mean ± SD) in the vertical direction (mesial) for implants placed in the region of 35, 36, 37 for Group A was 1.51 ± 0 mm, 1.51 ± 0 mm, and 2.47 ± 0 mm, respectively, and for Group B was 1.37 ± 0.32 mm, 1.65 ± 0.48 mm, and 1.79 ± 0.36 mm, respectively. The linear distance (mean ± SD) in the vertical direction (distal) for implants placed in the region of 35, 36, 37 for Group A was 3.37 ± 0 mm, 1.51 ± 0 mm, and 1.51 ± 0 mm, respectively, and for Group B was 1.86 ± 0.48 mm (P ≤ 0.05), 1.56 ± 0.23 mm, and 1.29 ± 0.39 mm (P ≤ 0.05), respectively. The angular deviation (perpendicularity) values for virtually planned implants (Group A) were 90.00° ± 0° and for implants placed in the region of 35, 36, and 37 (Group B) were 84.52° ± 5.4°, 83.57° ± 1.52°, and 80.41° ± 2.37°, respectively, which are highly significant (P ≤ 0.05). CONCLUSIONS: The stereolithographic universal open guide used in the study may be considered accurate for placement of implants in mesiodistal position and also in terms of perpendicularity but not in the vertical position. Stereolithographic open guide may be recommended for more accurate implant position, especially for the placement of multiple implants.

A finite element study of teeth restored with post and core: Effect of design, material, and ferrule.

BACKGROUND: Different postdesigns and materials are available; however, no consensus exists regarding superiority for stress distribution. The aim of this study was to evaluate the effect of design and material of post with or without ferrule on stress distribution using finite element analysis. MATERIALS AND METHODS: A total of 12 three-dimensional (3D) axisymmetric models of postretained central incisors were made: Six with ferrule design and six without it. Three of these six models had tapered posts, and three had parallel posts. The materials tested were titanium post with a composite resin core, nickel chromium cast post and core, and fiber reinforced composite (FRC) post with a composite resin core. The stress analysis was done using ANSYS software. The load of 100 N at an angle of 45΀ was applied 2 mm cervical to incisal edge on the palatal surface and results were analyzed using 3D von Mises criteria. RESULTS: The highest amount of stress was in the cervical region. Overall, the stress in the tapered postsystem was more than the parallel one. FRC post and composite resin core recorded minimal stresses within the post but the stresses transmitted to cervical dentin were more as compared to other systems. Minimal stresses in cervical dentine were observed where the remaining coronal dentin was strengthen by ferrule. CONCLUSION: A rigid material with high modulus of elasticity for post and core system creates most uniform stress distribution pattern. Ferrule provides uniform distribution of stresses and decreases the cervical stresses.

Two-Piece Hollow Bulb Obturator for Postsurgical Partial Maxillectomy Defect in a Young Patient Revamping Lost Malar Prominence: A Clinical Report.

The most frequent type of treatment for patients diagnosed with a malignant neoplasia of the oral cavity is surgical resection of the tumor. Ablative surgery may be followed by a reconstructive phase, in which the surgeon may choose between local flaps, nonvascularized bone grafts or free vascularized flaps to close the surgical site, depending on the general conditions of the patient. Esthetic and functional results are challenging to achieve for the prosthodontist, as variable amount of hard and soft tissues are removed. This report describes the fabrication of a two-piece hollow obturator for a 19-year-old patient who underwent wide surgical excision of the osteosarcoma of the maxilla and was rehabilitated to function. In this case, the surgical site was covered with submental flap, and the second piece of the obturator provided fullness to the lost malar prominence.

Evaluation of the marginal fit of metal copings fabricated on three different marginal designs using conventional and accelerated casting techniques: an in vitro study.

INTRODUCTION: Abundant resources and techniques have been used for complete coverage crown fabrication. Conventional investing and casting procedures for phosphate-bonded investments require a 2- to 4-h procedure before completion. Accelerated casting techniques have been used, but may not result in castings with matching marginal accuracy. AIMS AND OBJECTIVES: The study measured the marginal gap and determined the clinical acceptability of single cast copings invested in a phosphate-bonded investment with the use of conventional and accelerated methods. MATERIALS AND METHODS: One hundred and twenty cast coping samples were fabricated using conventional and accelerated methods, with three finish lines: Chamfer, shoulder and shoulder with bevel. Sixty copings were prepared with each technique. Each coping was examined with a stereomicroscope at four predetermined sites and measurements of marginal gaps were documented for each. STATISTICAL ANALYSIS: A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Evidence of marginal gap was then evaluated by t-test. Analysis of variance and Post-hoc analysis were used to compare two groups as well as to make comparisons between three subgroups . RESULTS: Measurements recorded showed no statistically significant difference between conventional and accelerated groups. CONCLUSION: Among the three marginal designs studied, shoulder with bevel showed the best marginal fit with conventional as well as accelerated casting techniques. Accelerated casting technique could be a vital alternative to the time-consuming conventional casting technique. The marginal fit between the two casting techniques showed no statistical difference.

Reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous using accepted facial dimensions recorded from dentulous subjects.

The study was undertaken to evaluate the reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous subjects using accepted facial dimensions recorded from dentulous subjects. The hypothesis was that facial measurements can be used to obtain the vertical dimension of occlusion for edentulous patients where no pre-extraction records exist. A total of 180 subjects were selected in the age groups of 50-60 years, consisting of 75 dentate male and 75 dentate female subjects for whom different facial measurements were recorded including vertical dimension of occlusion and rest, and 15 edentulous male and 15 edentulous female subjects for whom all the facial measurements were recorded including the vertical dimension of rest and occlusion following construction of upper and lower complete dentures. The left outer canthus of eye to angle of mouth distance and the right Ear-Eye distance were found to be as valuable adjuncts in the determination of occlusal vertical dimension. The Glabella-Subnasion distance, the Pupil-Stomion distance, the Pupil-Rima Oris distance and the distance between the two Angles of the Mouth did not have a significant role in the determination of the occlusal vertical dimension. The vertical dimension can be determined with reasonable accuracy by utilizing other facial measurements for patients for whom no pre-extraction records exist.

To evaluate the effect of various surface treatments on the shear bond strength of three different intraoral ceramic repair systems: an in vitro study.

Fractures of metal-ceramic restoration pose an esthetic and functional dilemma both for patient and the dentist. Intraoral repair systems eliminate the remake and removal of restoration. Many intraoral repair materials and surface treatments are available to repair intraorally fractured metal-ceramic restoration. Bond strength data of various materials and specific technique used for repair are necessary for predicting the success of a given repair system. This study evaluated the shear bond strength of three different intraoral repair systems for metal-ceramic restorations applied on exposed metal and porcelain surface. One hundred and twenty metal discs (20 mm in diameter × 0.7 mm thick) were fabricated with nickel-chromium alloy (Mealloy, Dentsply, USA). Feldspathic porcelain (Duceram, Degudent, Germany) were applied over one test surface of the discs in the thickness of 1.8 mm followed by conventional firing. The defect, which simulates clinical failures were created in 1/4th area of the metal-ceramic discs. The metal-ceramic discs samples were divided into ceramic substrate (Group I, n = 60) and metal substrate (Group II, n = 60), according to the defect location. Then, samples of ceramic substrate (Group I) and metal substrate (Group II) were subdivided into A, B according to the surface treatments (A; roughening with diamond bur and B; abraded with 50 µ Al2O3) and repaired with one of the intraoral repair systems tested (a. Ceramic repair system, Ivoclar Vivadent; b. Clearfil repair system, Kurary, c; Porcelain repair system, 3 M ESPE). All the repaired samples were stored in distilled water at 37 °C for 24 h. After thermocycling at 6-60° C, all the samples were stored at 37 °C for additional 7 days. Shear bond strength of all the samples were calculated by using Universal testing machine. The mean shear bond strength values for the group I (A/B) were as follows: Ceramic repair system (9.47 ± 1.41/14.03 ± 2.54 MPa), Clearfil repair system (14.03 ± 2.32/14.64 ± 2.28 MPa), and Porcelain repair system (14.41 ± 3.96/14.86 ± 3.10 MPa). The mean shear bond strength values for the group II (A/B) were as follows: Ceramic repair system (9.42 ± 1.44/18.61 ± 2.60 MPa), Clearfil repair system (14.44 ± 3.23/14.98 ± 2.73 MPa), and Porcelain repair system (11.86 ± 2.24/13.24 ± 2.72 MPa). Air abrasion with 50 µm aluminum oxide particles is the preferred surface treatment. Porcelain repair system showed the highest shear bond with air abrasion for ceramic substrate and for metal substrate Ceramic repair system showed the highest bond strength with air abrasion as a surface treatment. This study suggest that the three repair systems tested are adequate for intraoral chairside repair of metal-ceramic restoration when air abrasion is used for surface treatment of the substrate (Ceramic repair system, Ivoclar Vivadent, Germany; Clearfil repair system, Kurary, Japan; Porcelain repair system, 3M ESPE, Germany).

Reliability of anatomic reference planes in establishing the occlusal plane in different jaw relationships: a cephalometric study.

The purpose of this study was to evaluate the reliability of different anatomic reference planes in determination of Occlusal plane in dentulous and edentulous subjects with Angle's class I and class II Maxillomandibular relationship. Eighty subjects were included in the study which was divided into four Groups based on dentition and skeletal relationship. The Group I (n = 20) and Group II (n = 20) includes young and completely dentulous subjects in Angle's class I and class II relationship, respectively. The Group III (n = 20) and Group IV (n = 20) subjects were completely edentulous in Angle's class I and class II relationship, respectively. For all subjects, right lateral cephalograms were taken and cephalometric analysis was done and data obtained from cephalometric tracings were then statistically analyzed. The results showed no significant difference of angle between Occlusal plane and Frankfort Horizontal plane, Camper's plane and Palatal plane when Group I and Group III, and Group II and Group IV subjects were compared. The Frankfort Horizontal plane, Camper's plane and the Palatal plane may be used as a reliable guide to establish Occlusal plane in edentulous subjects in both Angle's class I and class II Maxillomandibular relationships.

Women and tobacco: a total misfit or mis-unfit.

Women smokers are likely to increase as a percentage of the total. If the percentage of women who smoke in developing countries rise to the levels of men smokers, there will be more than 500 million women smokers in the next generation. Because women who smoke die from the same tobacco-caused diseases as men, such an increase will have dramatic effects on women's health and on the health and incomes of their families. In addition, women smokers are also at risk for developing cancer of the reproductive organs and osteoporosis. A gender perspective contributes to a better understanding of the epidemiological trends, social marketing strategies, economic policies, and international actions relating to women and the tobacco epidemic.

A two-piece sectional interim obturator. A clinical report.

Prosthetic rehabilitation of acquired maxillary defects can be achieved satisfactorily if all facets of treatment planning and design considerations are taken into account before the rehabilitation process. Complications associated with maxillary defects limit treatment protocols to a great extent. The prosthodontist has to identify these problem areas and suitably devise feasible options and incorporate them in the design. In this report, an acquired maxillary defect with unfavorable undercuts in the defect was successfully treated by making a two-piece sectional obturator. The two pieces were connected by the use of double-die pin system. The methodology greatly reduced chairside time and number of visits, and effective obturation was satisfactorily achieved.

A comparative evaluation of static and functional methods for recording centric relation and condylar guidance: a clinical study.

To evaluate and compare the centric relation and horizontal condylar guidance using interocclusal wax and extra oral Gothic arch methods and subjective evaluation of dentures thus fabricated. Centric relation and horizontal condylar guidance was recorded by using interocclusal wax and gothic arch tracing in 28 completely edentulous patients. These records were transferred to the articulator and difference in both values was recorded. After that patients were divided in two groups according to the centric relation and horizontal condylar guidance recording method used to achieve balanced occlusion. Response of the dentures was subjectively evaluated using "Woelfel subjective evaluation criteria". Centric relation recorded by both the methods did coincide in 7.14 % of patients. Centric relation recorded by interocclusal wax was posterior to Gothic centric relation in 21.43 % of patients, and anterior to Gothic centric relation in 71.42 % patients. Gothic arch tracings gave higher mean guidance values on both the sides as compared to protrusive wax record in all the subjects, although the difference was statistically insignificant (P > 0.05). Subjective evaluation showed statistical insignificance for all the parameters in both groups. Gothic arch method records the centric relation at a more posterior position than the Static method, but it does not make any difference in clinical performance of the complete denture. Horizontal condylar guidance angle was approximately similar by both the methods.

A Comparative Study of the Stress Distribution in Different EndodonticPost-RetainedTeeth with and without Ferrule Design-A Finite Element Analysis.

Purpose. To analyze the stress distribution in an endodontically treated maxillary central incisor restored with various post-core systems and assess the benefit of ferrule using finite element analysis. Material and Methods. Twelve models with metal ceramic crown were created based on the combination of three types of post-core systems (titanium post-composite resin core, nickel-chromium post-core, and fiber reinforced composite resin post-composite resin core), two varieties of posts (tapered, parallel), and with or without ferrule. 100 N load was applied in three directions and the von Mises stress was compared. Results. Ferrule made no difference in stress distribution for the titanium and nickel-chromium posts, though it showed some stress reduction in fiber-reinforced composite resin posts. Nickel-chromium cast post-core transmitted the least amount of stresses to the dentin despite producing the maximum stress. Conclusion. Incorporation of ferrule offered some degree of stress reduction in nonmetal post, and it increased the stresses within cervical dentin.

Prosthetic rehabilitation of a patient with a large mid face defect secondary to Basal cell carcinoma.

The art of maxillofacial prosthetics restores esthetics and function in patients with gross developmental or acquired defects of face and helps them to restore hope and ambition to lead a useful life. This valuable service provided by maxillofacial prosthodontist lifts the morale of the patient and thus aids in physical well being and quality of life. Diagnosis and treatment planning should include attention to each detail prior to rehabilitation process. This paper describes a clinical case of mid face defect due to basal cell carcinoma, rehabilitated with facial prosthesis and intraoral obturator.

Oxidation heat treatment affecting metal-ceramic bonding.

AIM OF THE STUDY: There is dearth of literature regarding the effects of oxidation heat treatment (OHT) as surface pretreatments on bond strength of base metal alloys and porcelain. MATERIALS AND METHODS: Forty-five bar specimens of each two commercially available base metal alloys Mealloy and Wirorn-99 (were fabricated. Dimensions of each specimen were 15.0 × 2.0 × 0.5 mm (according to the ISO 6872-1984). According to the surface pretreatments the samples of the two groups were categorized into three subgroups: With OHT only, with sandblasting only (with Al2O3 of 110 µm) and with OHT and sandblasting. Application of commercially available Duceram porcelain in thickness of 2.00 mm was applied over the surface of metal with the pretreatments. Samples were then placed under SEM for EDX examination to evaluate ionic changes that occurred at the metal-ceramic interface. Flexural bond strength of each sample was calculated under Universal Testing Machine. RESULTS: The one-way ANOVA indicated no significant influence of either metal type (P=0.811) or any surface pretreatment (P=0.757) on the metal-ceramic bond strength. CONCLUSION: OHT resulted in the increase in amount of oxides at the metal-ceramic interface. However, neither metal type nor surface pretreatments affected bond strength.

Nonsurgical healing of large periradicular lesions using a triple antibiotic paste: A case series.

The infection of the root canal system is considered to be a polymicrobial infection, consisting of both aerobic and anaerobic bacteria. Because of the complexity of the root canal infection, it is unlikely that any single antibiotic could result in effective sterilization of the canal. A combination of antibiotic drugs (metronidazole, ciprofloxacin, and minocycline) is used to eliminate target bacteria, which are possible sources of endodontic lesions. Three case reports describe the nonsurgical endodontic treatment of teeth with large periradicular lesions. A triple antibiotic paste was used for 3 months. After 3 months, teeth were asymptomatic and were obturated. The follow-up radiograph of all the three cases showed progressive healing of periradicular lesions. The results of these cases show that when most commonly used medicaments fail in eliminating the symptoms then a triple antibiotic paste can be used clinically in the treatment of teeth with large periradicular lesions.

Full-mouth rehabilitation of a case of generalized enamel hypoplasia using a twin-stage procedure.

The dilemma confronting many dentists today is that innovations and well-defined specializations have greatly enlarged the treatment realm for tooth preservation as well as tooth replacement. The objectives should be preservation of the remaining tooth structure, restoration of optimum function, esthetics with least invasive procedures, cost effective, and short treatment time. The number of remaining natural teeth is one of the most widely used method for evaluating oral health and the prosthetic treatment of patients with a mutilated dentition. Though the treatment of these patients can be complex, but there are some important principles applicable in most cases. This case report demonstrates a satisfying full mouth rehabilitation using the Hobo and Takayama twin-stage procedure for a patient with esthetically and functionally compromised dentition. The final prosthesis with this twin-stage technique ensured a restoration with a predictable posterior disclusion and anterior guidance in harmony with the condylar path.