Artificial Crowns Research Articles

The dental perspective on osteogenesis imperfecta in a Danish adult population

BackgroundTo report on dental characteristics and treatment load in Danish adult patients with osteogenesis imperfecta (OI).MethodsOral examination of 73 patients with OI was performed and OI type I, III, and IV were represented by 75.3%, 8.2%, and 16.4%, respectively. Patients were diagnosed as having dentinogenesis imperfecta (DI) if they had clinical and radiological signs of DI. In the data analysis, mild OI (type I) was compared to moderate-severe OI (type III and IV).ResultsDiscoloration of teeth was prevalent in patients with moderate-severe compared to mild OI (83.3% vs. 5.5%, p < 0.001). Cervical constriction and pulpal obliteration were frequent findings in patients with moderate-severe OI (61.1% and 88.9%, respectively), whereas pulp stones and taurodontism were diagnosed in patients with mild OI only (29.1% and 9.1%, respectively). DI was found in 24.7% of OI patients and considerably more frequent in patients with moderate-severe (94.4%) compared to mild OI (1.8%) (p < 0.001). The number of teeth with artificial crowns was significantly higher in patients with moderate-severe OI than in patients with mild OI (median 1.5, range 0–23 vs. median 0, range 0–14) (p < 0.001). The number of teeth with fillings in patients with mild OI was significantly higher than in patients with moderate-severe OI (mean 9.7, SD 5.1, median 9.0, range 1–21 vs. mean 5.0, SD 4.4, median 4.0, range 0–16) (p < 0.001).ConclusionsOne fourth of patients with OI had DI, and the vast majority of them had moderate-severe OI. Whereas discoloration of teeth, cervical constriction and pulp obliteration were frequent findings in patients with moderate-severe OI, pulp stones and taurodontism were found in patients with mild OI only. In patients with moderate-severe OI, the dental treatment load was dominated by prosthetic treatment, whereas restorative treatment with fillings was more prevalent in patients with mild OI.

Perubahan Rasio Ekspresi mRNA MMP-8/TIMP-1 Setelah Aplikasi Gel Ekstrak Bunga Rosella 10% pada Pasien dengan Gingivitis Setelah Pemasangan Mahkota Tiruan Akrilik

The acrylic-resin crown is still used as a choice in the manufacture of artificial crown because it is easy in the procedure. However accumulation plaque around cervical of the acrylic-resin crown can lead to the occurrence of gingivitis. Some research found that degradation of ECM by MMP-8 and TIMP-1 as a inhibitor during gingivitis. Roselle as a herbal plant in the treatment began to increase. Roselle is rich in Phytochemical compound which has been shown to reduce inflammation. This research determined effectiveness of roselle extract gel 10% in reducing gingivitis in patients using acrylic-resin crown and related to changes in mRNA MMP-8/TIMP-1 gene expression ratio. The subjects were 9 patients who has gingivitis post resin-acrylic crown insertion and divided in to three groups treatment with roselle extract gel 10%, negative control (base gel), and positive control (Povidon iodine). GCF samples were taken in cervical area of acrylic-resin crown with paper strips before and seven days after application of roselle extract gel 10%. The change of ratio MMP-8 and TIMP-1 m RNA gene expression is tested using Real Time-Polymerase Chain Reaction. Paired- T test shows on negative control group (p=0,301, p&lt;0,05) does not show any change ratio of mRNA MMP- 8/TIMP-1, on positive control, there is changing ratio but not significant(p =0,060). The treatment group shows significant change in ratio of mRNA MMP-8 /TIMP-1 gene expression(p=0,018) Conclusion, Extract Roselle gel 10% can reduce the gingivitis and change the ratio of MMP-8 / TIMP 1 mRNA.

ПУЛЬПОТОМИЯ ПРИ ПРОТЕЗИРОВАНИИ ЗУБОВ. ПИЛОТНОЕ ИССЛЕДОВАНИЕ

The subject. Significant preparation of the teeth for metal-ceramic or ceramic crowns in most cases is accompanied by a preliminary devitalization of the teeth, which shortens the period of their survival. The problem of ensuring the vitality of supporting teeth can be solved by amputating only the coronal pulp, which inevitably overheats during preparation, while retaining the root pulp. The skeptical attitude of dentists to vital pulpotomy may be explained by the often unsuccessful (ineffective) use of this method for teeth with already affected pulp. The hope for success in this study is based on the choice of intact teeth for vital pulpotomy of subsequent prosthetics. Urgency. The amputation method of endodontic dentistry is not used for prosthetic purposes. This can be explained by its low efficiency when using teeth with inflamed pulp. The aim of the work is to confirm the effectiveness of vital pulpotomy in a typical dental situation and subsequent prosthetics. Methodology. Clinical observation of the patient before and during 1 year after treatment, with the use of clinical and modern paraclinical methods of examination. Diagnosed. Treatment is planned: removable denture on the upper jaw with a preliminary shortening of the tooth 46 and subsequent use of a metal-ceramic crown. Significant sosotoyanie hard tissues of the tooth 46 and the subsequent preparation for artificial crowns required endodontic-specific training. It was supposed to preserve the root pulp (vital pulpotomy). As a result, there were no complaints at the control examination 1 year after pulpotomy. The pain threshold from the electrode was 11 µa. Summary. The vital pulpotomy of the tooth with intact pulp showed the possibility of its effective prosthetics with an artificial crown while maintaining the viability of the root pulp. The technique of introduction of the electrode into the cavity of the tooth allowed to conduct direct measurements of the pain threshold of the root pulp in the dynamics of (application for invention No. 2017115518/17(026915) from 02.05.2017).

Способ контроля и коррекции края искусcтвенной коронки к десневому валику.

Способ контроля и коррекции края искусcтвенной коронки к десневому валику.

The use of functionally graded dental crowns to improve biocompatibility: a finite element analysis

In post-core crown restorations, the significant mismatch between stiffness of artificial crowns and dental tissues leads to stress concentration at the interfaces. The aim of the present study was to reduce the destructive stresses by using a class of inhomogeneous materials called functionally graded materials (FGMs). For the purpose of the study, a 3-dimentional computer model of a premolar tooth and its surrounding tissues were generated. A post-core crown restoration with various crown materials, homogenous and FGM materials, were simulated and analyzed by finite element method. Finite element and statistical analysis showed that, in case of oblique loading, a significant difference (p < 0.05) was found at the maximum von Mises stresses of the crown margin between FGM and homogeneous crowns. The maximum von Mises stresses of the crown margin generated by FGM crowns were lower than those generated by homogenous crowns (70.8 vs. 46.3 MPa) and alumina crown resulted in the highest von Mises stress at the crown margin (77.7 MPa). Crown materials of high modulus of elasticity produced high stresses at the cervical region. FGM crowns may reduce the stress concentration at the cervical margins and consequently reduce the possibility of fracture.

Root Canal Morphology of Maxillary Premolars among the Elderly.

Root Canal Morphology of Maxillary Premolars among the Elderly.

The positioning of prosthetic Margo against gingival Margo, cause or not, of periodontitis

Background: The long, severe contour of prosthetic margo, remnants of cement used for adhesion, these are elements that affect the periodontal status of gingival margo, and then, the care of oral hygiene by the patient, affecting further aggravated gingival infection to fixed further in periodont.Methods: The experiment was conducted in 3 mice, to which were placed metal artificial crowns. It was controlled the effect of the mechanical action of prosthetic margo, established subgingival, agains the marginal gingival tissue.Results: The periodontal status was performed 1 week, 2 weeks, 3 weeks and 1 month later, after placing the crows. After 2 months, was taken the samples of saliva for laboratory, to analyze the bacterial flora in the areas of the presence of gingival margo at the prosthetic crown.Conclusions: The presence of plaque that is not mechanically disconnected from gingival sulcus, influences the periodontal diseases that shows its characteristics, reflected significantly after 7 days, after 14 days, after 21 days. Signs of gingival inflammation are significant features of the evolution of related of periodontal illness, according to these dates already referred to us above.

Occlusion and Disocclusion Time Changes in Single Unit Crowns Designed by Functional Generated Path Technique: A Randomised Clinical Trial

Although it is believed that implementation of the functional generated path (FGP) technique can facilitate occlusal surface design for restorations, it has not been objectively compared in situ with the conventional fabrication yet. Therefore, in the present study, a single-blind crossover clinical trial was conducted using T-scan to compare changes in occlusion time (OT) and disocclusion time (DT) of single posterior artificial crowns designed differently using FGP technique (FGP), average-value FGP technique (AVR) and conventional fabrication (CON). Each of the 10 participants took part in the study tried three artificial crowns in different sequences according to a computer generated randomization list. The results objectively revealed that changes in OT and DT were significantly smaller for FGP than CON (P < 0.05) and considerably smaller for AVR than CON, respectively. The subjective feedback and the occlusal adjusting time were better and shorter for FGP and AVR than CON (P < 0.05). No harm to the participants occurred. Overall, FGP is an efficient technique showing more physiological harmonious relationship with the articulating system.

Currently used systems of dental posts for endodontic treatment

An advanced stage of a tooth decay promotes an extremely damaged tooth that needs endodontic treatment to be restored. When satisfactory coronal tooth structure remains, an artificial crown can be placed without a post. On the other hand, the treatment of seriously damaged teeth often require an endodontic post. The main reason for using post is to enable rebuilding of the tooth structure prior to crown restoration. Dentists believe that endodontic posts provide a stable and solid restoration of the tooth, as well as providing strengthening of the tooth root, which constitutes the solid basis for a dental crown restoration. However, some authors reported that the strength of the tooth is directly related to the remaining dentin, and because of that, an endodontic treatment can present a higher risk of biomechanical failure. A number of different materials have been used for the manufacturing of dental posts. The fundamental posts requirements include high tensile strength, high fatigue resistance to occlusal and shear loading and a good distribution of the forces affecting the tooth root. The purpose of this article is to review the current literature and identify the various characteristics of a dental post, as well as some principles on the endodontic treatment for tooth decay.

REVIEW OF THE BASIC MECHANICAL PROPERTIES OF STRUCTURAL CERAMIC MATERIALS USED FOR THE MANUFACTURE OF PROSTHESES IN A SINGLE TOOTH (ARTIFICIAL TOOTH CROWNS, INLAYS, VENEERS)

The aim of this work was to obtain data of the strength properties of structural ceramic materials used in the manufacture of non-metal constructions of dentures. As a method of ceramic processing was the selected method waterjet cutting. Was obtained for 10 samples Lacanau ceramic, hybrid and feldspatic ceramic. According to ISO 6872 conducted testing of samples for strength by the method of three-point bending. On the basis of your data we recommend that the materials exclusively for the manufacture of artificial crowns import and sale within the length of one tooth, such as inlays and veneers.

A step ahead in post and core technique for patients with limited interarch space

The successful treatment of a badly broken down tooth with pulpal disease depends not only on a good endodontic therapy but also on a good prosthodontic reconstruction of the tooth following the root canal treatment. Often, we come across an endodontically treated tooth with little or no clinical crown. In such cases, a postspace is prepared into the canal for the cementation of post and an artificial crown structure called the core is prepared over it to support the fixed partial denture. Post and cores though commonly used now have their own limitations. Failures associated with these systems include the loss of retention of posts and fracture of roots or even root perforations. Moreover, placement of a post in situations with limited interarch space is a challenge for any dentist. The failure rate associated with the conventional techniques would be higher in these conditions. This case report discusses an alternative technique of restoration of a badly broken down endodontically treated tooth with a specially designed post and core attachment to provide the necessary resistance and retention form for the overlying prosthesis in patients with limited interarch space.

In vivo evaluation of the exposure to aluminium, cobalt, chromium, copper, nickel, titanium and vanadium in oral mucosa cells from orthodontic patients with mini-implants by Inductively coupled plasma-mass spectrometry (ICP–MS)

Statement of problem. The biocompatibility of titanium has been well documented, but clinical outcomes of ceramic-veneered titanium restorations were not conclusive. Purpose. The study presents the results of a 5-year clinical study of individual crowns and fixed partial dentures (FPDs) veneered with a low-fusing ceramic of the Procera system. Material and methods. All patients at one clinic who required crowns or FPDs during a 2-year period were invited to participate. A total of 260 patients received 333 ceramic-veneered Procera restorations (242 single crowns and 91 FPDs). Clinical registrations were performed annually, and the restorations were evaluated according to the California Dental Association rating system. At the 5-year follow-up, 198 (76%) patients were examined. Most of the loss of patients could be explained. Results. Practically all Procera restorations were judged as satisfactory both at baseline and follow-up examinations. One artificial crown and 1 FPD were remade because of extensive fractures of ceramic veneers. Two FPDs had fractures of a soldered joint, but only 1 FPD was replaced. Some minor complications occurred, such as small porcelain fractures that could be polished (6% of single crowns, 13% of FPDs) and or loosened restorations that were recemented. Other recorded complications were not related to the Procera system but to dental caries, loosened posts and cores, and root fractures. Conclusion. Clinical outcomes over a 5-year period for ceramic-veneered titanium restorations with the Procera system were favorable. (J Prosthet Dent 2000;84:514-21.)

Tribological behaviour of unveneered and veneered lithium disilicate dental material

The friction and wear behaviour of a lithium disilicate dental ceramic against natural dental enamel is studied, including the effect of the presence of a fluorapatite veneering upon the tribological properties of the material. The tribological behaviour was assessed using reciprocating pin-on-plate test configuration, at pH 3 and pH 7. The surface energy of the plates was determined, as well as the zeta potential of fluorapatite, lithium disilicate and enamel particles in artificial saliva.It was found that the friction and wear behaviour of the tested enamel/plate material tribocouples is less severe in unveneered plates. Initial surface roughness of the plate does not affect wear results. However the topography of the resulting wear track affects the corresponding wear loss: a smoother final wear track is associated with lower wear. The surface topography of the wear track, and thus the tribological performance of the tested materials, is very sensitive to the pH of the sliding solution. This is because the dissolution trend, wettability and surface charge of the used materials are pH dependent. Overall friction and wear are higher under basic pH conditions, especially when plates are veneered. A wear model is proposed that correlates the effect of the described parameters with the observed tribological behaviour at pH 7.Attained results show that fluorapatite coating of lithium disilicate dental crowns affects tooth/crown wear behaviour, resulting in increased wear of both the artificial crown and the opposing natural teeth. Coating should therefore be avoided in occlusal crown surfaces.

Study of bond strength of an artificial tooth crown on a new post-and-core inlay (laboratory studies)

One of actual problems of orthopedic stomatology is prosthetics of patients with low and destroyed clinical crowns. The objective of the research is the study of the quality of fixation of artificial crowns on the new post-and-core of our and known construction using different permanent fixing materials. The experimental groups of phantom samples served as the object of the study.

Effect of oral prophylactic instrumentation on the surface texture of all metal restorative materials.

Introduction:In the inaccessible areas on the crown the removal of calculus and stains by hand and ultrasonic instrumentation is the method for cleaning to preserve and increase the longevity of the restoration. However, when oral prophylaxis is performed on restorative crowns, it may produce some surface alterations and may favour plaque accumulation.Statement of Problem:Many patients may have restored their teeth with artificial crowns and would come to the dental office for oral prophylaxis. If a routine oral prophylaxis is followed, its effect on the restorative materials and the plaque accumulation can be studied.Materials and Methods:A total of 15 disc shaped wax patterns were invested and casted for cast titanium (Group A) and the remaining 15 disk shaped for nickel-chromium (Group B). The obtained castings were finished and polished. All the specimens were subjected to hand and ultrasonic scaling for 15 s. Profilometer and scanning electron microscopic was used to analyze and evaluate the surface roughness. Specimens of each group were embedded on the anterior lingual aspects of the removable lower retention plates. 5 volunteers were asked to wear it in the mouth for 24 h for 7 days. After 7 days, the specimens were stained with plaque disclosing solutions and the photomicrographs were taken by the optical stereomicroscope and the plaque accumulations were assessed in percentage.Results:The difference in average surface roughness (μm) of the polished test specimens was maximum for ultrasonic scaling than hand scaling and maximum for Group A than Group B. Plaque accumulation in percentage on the treated specimens was found to be nonsignificant but, mean plaque accumulation was maximum on ultrasonic scaling surface than hand scaling and maximum for Group A than Group B. Surface roughness was found to be statistically significant after hand scaling (F = 9.377, P = 0.000) and ultrasonic scaling (F = 5.373, P = 0.0000) by Student t-test.Conclusion:The Surface roughness and plaque accumulation on the specimens were more for Group A than Group B and maximum produced by ultrasonic scaling than hand scaling.

Influence of Full Veneer Restoration on Fracture Resistance of Three Different Core Materials: An Invitro Study.

One of the factor which affects the strength of the tooth restored with core material is the property of the material. In clinical situation all such restored teeth are protected by crowns. This study evaluated the strength of different core materials on a compromised tooth structure after restoration with a crown. Seventy extracted intact human premolars were collected and mounted within a mould using auto-polymerizing resin. The teeth were divided in-to four groups - A, B, C and D. Each group contained 20 teeth except group A with 10 teeth. All the teeth were prepared for full veneer cast crown. Except for the teeth in group: A) extensive class-I cavities were prepared in the teeth of all the groups and restored with; B) composite resin, 3M EPSE Filtek P60; C) Silver reinforced glass ionomer, SHOFU Hi Dense XP and; (D) Resin reinforced glass ionomer, GC Gold Label light cure GIC. All the teeth were restored with cast-metal alloy and exposed to 1.2 million cycles of cyclic loading in a chewing simulator. Subsequently, the teeth that survived were loaded till fracture in the universal testing machine. Fracture loads and type of fractures were recorded. All the specimens survived cyclic loading. The mean fracture strength of the silver reinforced glass ionomer was greater with and without crown (p<0.001). Statistical analysis for the mean fracture load of each specimen showed significant difference between the groups. Under the condition of this study, core materials when restored with artificial crown had a significant increase in fracture resistance.

Evaluation of the thickness of facial anterior gingiva and posterior palatal mucosa by transgingival probing

The gingival morphology of the maxillary anterior region plays an important role in determining the final aesthetic outcome as it is associated with the outcomes of periodontal therapy, root coverage procedures and implant esthetics.1 Biotype defined as part of body having the same genotype. The identification of the gingival biotype may be important in clinical practice since difference in gingival and osseous architecture have been shown to exhibit a significant impact on the outcome of restorative therapy.2 The stability of the osseous crest and soft tissue is directly proportional to the thickness of the bone and gingival tissue. The term gingival or periodontal phenotype has recently been coined by Seibert and Lindhe3 to address a common clinical observation of great variation in thickness and width of facial keratinized tissue and they categorized the gingiva into thick and thin. The thick gingiva is characterized as bulky, slightly scalloped gingival margins with short wide teeth and the thin gingiva is characterized by highly scalloped gingival margins with slender teeth.2,3 Claffey and Shanley4 defined that the gingival tissue biotype is thin if gingival thickness is <1.5 mm and thick if its thickness is = 2 mm. It is a widely accepted clinical impression that a thin, highly-scalloped gingiva tends to recede from source of irritation (artificial crown margin or microbial irritants) and gingival recession often occurs following traumatic or surgical injury.

“Elucidating the Problem of Pier Abutment through the Use of a Fixed Movable Prosthesis – A Clinical Case Report”

Many times a dental practitioner comes across a situation where his clinical dexterity and knowledge can make the difference between a patient being delivered a removable or a fixed prosthesis. One such clinical situation is existence of a pier abutment in between two edentulous areas. Managing such a partial edentulous situation with a fixed partial denture can be successfully accomplished by those who understand basic principles of using a non-rigid connector, custom made in the laboratory. Clinical application of mandibular movements on the occlusal anatomy of artificial crowns is an essential component in such cases besides adequate education and motivation of the patient. This article in the form of a clinical case report describes the management of pier abutment case over a period of 5 years with a fixed movable prosthesis. A custom made design in the laboratory allows the pier abutment to support two different prostheses on either side, without undergoing any retentive or biological failure of the abutment. Moreover the flexible design also allows the patient to benefit from fixed prosthesis rather than a conventional removable prosthesis.

Dental procedures in 24 patients with chronic immune thrombocytopenia in prospective clinical studies of eltrombopag

Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by chronically low peripheral blood platelet counts. Eltrombopag is an oral, non-peptide, thrombopoietin-receptor agonist that increases platelet production. This report examines peri-procedural platelet counts and bleeding complications among chronic ITP patients requiring dental procedures while participating in clinical studies with eltrombopag. A total of 494 patients participated in five clinical studies of eltrombopag in chronic ITP. Information about dental procedures was collected prospectively in four studies and retrospectively in one study. Twenty-four patients (22 eltrombopag, 2 placebo) underwent 32 dental procedures (dental cleaning, tooth repair, artificial crown, dental prosthesis, tooth extraction, dental or wisdom teeth extraction, dental root extraction, and endodontic procedures, among others) during study treatment or up to 10 days later. Supplemental ITP therapy (e.g., corticosteroids, platelet transfusions) was given before the dental procedure to increase platelet counts in three eltrombopag-treated patients and both placebo-treated patients. The mean pre-procedure platelet count ± standard deviation for all procedures in the overall population of patients, eltrombopag group, and placebo group prior to undergoing dental procedures was 96 000 ± 81 069/µl,103 517 ± 81 522/µl, and 23 333 ± 9291/µl, respectively. Two patients in each group had platelet counts below 30 000/µl before the procedure. No patient who had a dental procedure experienced a bleeding adverse event. Among patients with chronic ITP who required a dental procedure during clinical studies of eltrombopag, supplemental ITP treatment was required for both patients who received placebo but was not required for most patients who received eltrombopag. No bleeding complications were reported. These data imply that patients with chronic ITP who receive eltrombopag and experience increases in platelet counts fulfill current pre-procedural platelet count recommendations to undergo invasive dental procedures, and may have a lower risk of bleeding complications and a reduced need for supplemental ITP treatment.

Stress analysis of dental implants

Natural teeth consist of the crown and the root. Due to periodontal disease or by an injury, a natural root may be damaged, and it may be incapable of supporting the teeth and bear chewing forces. Under these circumstances, the root may be replaced by an implant. There are commonly three parts to what is described as an implant-the implant device itself ,the abutment-the piece that connects the implant device to artificial crown (teeth). Dental implants are predominantly made of titanium, which offers strength and durability as well as a unique property of fusing directly to bone-the process known as osseointegration. This paper deals with the finite element analysis of dental implant and surrounding bone structure after obtaining 100% osseointegration. This study reveals the stress distribution in implant-bone structure. This study can give suggestion for the area of implant-bone interface that is to be preserved to maintain its optimum functionality and design modification on dental implants.