Artificial Dentures Research Articles

Incisive Papilla Line as a Guide to Predict Maxillary Anterior Tooth Display

Oh and Hansen Oh and Hansen Maxillary anterior tooth display should be predicted and controlled for an esthetic outcome in an edentulous patient.1 The customary prosthodontic procedure requires an occlusion wax rim to be contoured for adequate lip support and occlusal vertical dimension determination.2 The lip line is marked on the rim when the patient is in the full smile to determine the amount of tooth display and guide the selection of the artificial denture teeth. However, the smile line is dynamic, and the degree of anterior tooth display will vary depending on gender, race, lip fullness, age, and upper lip length.3,4 The upper lip length is measured from the base of the columela to the tip of the philtrum to aid in the selection and positioning of the anterior teeth.3 In general, the longer the upper lip, the less the maxillary teeth are visible, and vice versa. However, the lip length as measured according to the facial morphology may not always provide an accurate estimation of the relative amount of tooth display, both at rest and in the full smile, because of a large variability in maxillary lip line relative to the incisal edge position.3,4 The incisive papilla remains relatively constant in both vertical and horizontal locations, except when combined with excessive resorption of alveolar bone, and is frequently used as an anatomic landmark in arranging maxillary anterior teeth.2,5-7 The mean vertical distance between the incisive papilla and the incisal edges of maxIncisive papilla line as a guide to predict maxillary anterior tooth display

Remount cast fabrication for occlusal equilibration against artificial denture teeth

aClinical Associate Professor, Department of Biologic and Materials Sciences, Division of Prosthodontics. bClinical Assistant Professor, Department of Biologic and Materials Sciences, Division of Prosthodontics. (J Prosthet Dent 2009;101:350-351) Establishment of a balanced and harmonious occlusion is a prerequisite for the successful rehabilitation of edentulous patients.1,2 Clinical remounting of the prosthesis simplifies the occlusal equilibration procedure by enhancing the visual detection of occlusal discrepancies, ensuring the accuracy of occlusal adjustments, and minimizing the errors occurring from the viscoelastic nature of the mucosa.1,2 The occlusal relation is evaluated visually by closing the artificial denture teeth against the opposing stone cast, and occlusal contact marks are identified with repeated impact and gliding contacts by means of articulating papers or ribbons placed between the denture teeth and the stone teeth.3,4 Gypsum material is readily accessible, convenient to use, and rigid; however, the stone teeth are not as tough as the artificial denture teeth and are brittle and susceptible to wear and breakage with repeated occlusal contact.3,4 Several methods have been introduced to address the problems of wear, chipping, or fracturing of the stone teeth against the opposing denture teeth. The remount casts are fabricated of low-fusing metal alloy,5 vinyl polysiloxane (VPS) impression material,6 or a combination of VPS, acrylic resin, and dental plaster.7 A cast made of low-fusing metal alloy addresses the problems associated with the weakness of the gypsum materials. It is durable and wear resistant; however, the procedure requires special materials and devices.5 In addition, incorporation of bismuth in the alloy (48-55%) to reduce shrinkage may present health hazards with the inhalation of the fumes developed when burnt out. The method using VPS material facilitates the remounting procedure because it is quick and easy to use and permits the rigid portion of the denture to pass into the undercut area.6,7 The block-out procedure may not be an important consideration because of the resiliency of the silicone material. In addition, the material is resistant to wear or chipping during occlusal adjustment. However, the accuracy of the occlusal contact marks indentified against the silicone tooth is suspect because of the viscoelastic nature of the silicone material. The resiliency of the silicone material may be managed by processing acrylic resin in the incisal or occlusal one third of the silicone tooth.7 This method may provide a stiffer surface against the artificial denture tooth; however, it requires a number of materials and procedures in which dowel pins are inserted into the acrylic resin to connect with the silicone material and dental plaster. The purpose of this article was to describe a simple and accurate procedure of fabricating a remount cast, in which a thin layer of tooth-colored acrylic resin is processed over the gypsum material to present a stiff, wear resistant, and tough surface that can endure the repeated impact and gliding occlusal contacts against the artificial denture teeth. The impression is lined with a thin layer of acrylic resin and poured in dental plaster. Polymerization of the acrylic resin is accelerated with heat from the exothermic reaction of the dental plaster. The acrylic resin shell is secured to the dental plaster by engaging undercuts presented by the tooth and tissue contours. The impression should be stored in a humid environment, and the potential dimensional change of the acrylic resin with polymerization is negligible with the use of a minimal volume of resin. The occlusal contact marks are readily identified on the denture teeth and the tooth-colored acrylic resin surface for an accurate assessment and selective adjustment of occlusion. This procedure can also be extended to fabricate a remount cast for a removable partial denture.

Mesenchymal Stem Cells and Tooth Engineering

Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.

Impacted Denture in the Oesophagus: Case report and review of Literature

Objective: To report a rare case of impacted foreign body (artificial denture) in the oesophagus and review the literature. Case Report: This is a case report of impacted foreign body (artificial denture) in the oesophagus. The wire could be seen on xray soft tissue neck lateral view. But rigid oesphagoscopy could not remove the denture and the patient developed cervical emphysema in the first post operative period. Foreign body (artificial denture) was removed by Oesophagotomy and retrieval of denture and sternocleidomastoid muscle patching via external approach. Conclusion: Foreign body ingestion is a common problem. Early removal of foreign bodies must be considered to reduce the risk of complications. Impacted denture in the oesophagus which was removed by oesophagotomy is an unusual presentation. To the best of our knowledge this is the first case report from Nepal.

Two-body wear of resin and ceramic denture teeth in comparison to human enamel

Objectives To evaluate the two-body wear resistance of different artificial denture teeth when opposed to steatite ceramic balls in a dual-axis chewing simulator. Methods Artificial denture teeth including the ceramic tooth Bonartic CT ®, the composite resin tooth Condyloform II NFC ®, the acrylic resin teeth Bonartic TCR ®, Orthognath ®, Polystar Selection ®, SR Orthotyp DCL ®, and Vitapan Cuspiform ®, and human maxillary premolars were tested in a chewing simulator. Wear resistance was analyzed measuring vertical substance loss and volume loss using profilometry and an optical macroscope after various chewing cycles (49 N, up to 1,200,000 cycles). Data were statistically analyzed using one-way analysis of variance (ANOVA) followed by the Fisher test (LSD) at p ≤ 0.05. Results After 1,200,000 chewing cycles the mean vertical substance loss and volume loss for the composite resin teeth (117 μm and 0.144 mm 3) were significantly lower than for all acrylic resin teeth (149–166 μm and 0.220–0.292 mm 3) ( p ≤ 0.05), but higher than for ceramic teeth (36 μm and 0.029 mm 3) and for enamel (56 μm and 0.033 mm 3) ( p ≤ 0.05). No significant differences were found among the acrylic resin teeth for both parameters ( p > 0.05). Significance The composite resin showed improved in vitro two-body wear resistance compared to modern acrylic resin denture teeth; however, it showed less wear resistance than ceramic teeth and human enamel. Ceramic teeth should be preferred over natural teeth when occlusal stability is considered a high priority.

The Ileum: An Unusual Site Of Perforation By A Swallowed Artificial Denture

The Ileum: An Unusual Site Of Perforation By A Swallowed Artificial Denture

Removal of foreign body from the trachea: An unusual method.

Tracheobronchial foreign bodies can be sometimes very difficult to remove. This may be related to the location and type of foreign body, experience of the bronchoscopist and the availability of appropriate instruments.([1]) We report a case of an uncommon foreign body (artificial denture) in the trachea in an adult female following extubation after Lower Segment Caesarian Section (LSCS) in whom conventional methods to remove it failed. The foreign body was eventually removed via tracheostome using rigid bronchoscope and forceps.

The Effect of Nucleators on the Quality of the Surface of Glass-Ceramic Denture Coatings

The effect of nucleator additives on the surface relief and the degree of crystallization of material intended for the dentine and enamel layers of artificial denture is considered. It is established that hydroxyapatite additive is optimal for producing the required relief in the prime and dentine layers.

Dents artificielles et prothèse amovible

The final success of a treatment by a denture depends, among other factors, on artificial teeth. Artificial denture teeth replace missing natural teeth on the dental arches, but also restore the patient’s aesthetics, and each of the perturbed functions (such as mastication, phonation, and deglutition). Prosthodontic rehabilitation of the partially or totally edentulous patient imposes the practitioner a difficult selection among the numerous commercially available artificial denture teeth. Materials and their physical properties, size, shape and shade must be taken into consideration when selecting the appropriate artificial teeth.

Diamond-like carbon coatings on orthodontic archwires

Shape memory alloys (SMAs) of Nickel–titanium (NiTi) have attractive properties for biomedical applications because of their unique characteristics such as superelasticity, and shape memory effect. Therefore, their particular mechanical properties are utilized as orthodontic archwires in the field of dentistry. While, with increasing number of orthodontic treatments using devices containing nickel, there is a growing prevalence of nickel allergy. This is based on the fact that the corrosion of NiTi causes Ni release when immersed in oral saliva. Diamond-like carbon (DLC) films have many superior properties such as extreme hardness, low friction coefficients, chemical inertness, and high-corrosion resistance. This study focuses on DLC films deposited on orthodontic archwires in order to estimate the release of Ni ions in the physiological saline. The concentrations of Ni ions were detected by microwave introduced plasma mass spectrometry (MIP-MS). The DLC coating has found to dramatically protect the Ni release. The results indicated that DLC films could be applied to the implanted dental devices such as orthodontic archwires, and artificial dentures.

‘Artificial Dentures’ Being Discordant Narratives of the Dreams of Irma's Injection

Freud told Fliess, in June 1900, that he recorded and analysed the dream of Irma's injection on 24 July 1895 and thus the Secret of Dreams was unveiled. The author finds no evidence to substantiate Freud's account for discovering the wish-fulfilment (Wunscherfullung) theory of dreams. New readings of Freud's contemporaneous texts offer radically different narratives from that single teleological Eureka plot subsequently popularized by Jones. New datings for the production of The Interpretation of Dreams invite a re-evaluation of those texts which still constitute the specimen dream of psychoanalysis.

PROSTHODONTICS IS IN YOUR FUTURE

Several decades ago, prosthodontic procedures dominated dentistry. Teeth were extracted on a routine basis and artificial dentures were made for patients when natural teeth could have been saved using the techniques of today. Removable complete prosthodontics was prominent. Preventive dentistry, including better patient education about oral hygiene, fluoride application and proper diet, has since started to be promoted by the dental profession. Saving teeth instead of extracting them became popular and was valued by the public.

Internal platinum, palladium, and gold exposure in environmentally and occupationally exposed persons

In a pilot study the urinary platinum (Pt), palladium (Pd), and gold (Au) excretion was analyzed in 27 dental technicians, 17 road construction workers and 17 school-leavers using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Detection limits in urine were 0.24 ng/l for Pt and Au and 0.17 ng/l regarding Pd. A standardized questionnaire was used to assess information about kind and degree of contact to these metals, the physical condition of the volunteers and confounding factors. Significant differences between the three study groups were found. The mean Pt, Pd, and Au excretions of the dental technicians were significantly higher than those of the road construction workers and school-leavers. This indicates that the occupational treatment of dental alloys leads to an internal exposure to these metals which is distinctly higher than that from automobile exhaust exposure. Significant differences between Monday morning (pre-shift) and Thursday afternoon (post-shift) urine samples of the dental technicians were not found. The Pt excretion of road construction workers working near a much traveled highway was comparable with that of school-leavers being less (only environmentally) exposed to automobile exhaust. Regarding Pd and Au the road construction workers showed a tendency to higher levels in urine when compared with the school-leavers, but statistically significant differences were not found. The tendency to higher urinary Pd and Au levels in the road construction workers may be explained by their slightly greater number of noble metal containing artificial dentures, which may cause an additional exposure. A statistically significant effect of age on the urinary noble metal excretion was not detectable.

Dynamic Mechanical Properties of Artificial Teeth.

The purpose of this investigation is to evaluate the dynamic viscoelastic properties of artificial denture teeth using a viscoelastic spectrometer. Specimens were porcelain and resin teeth mounted in denture base. The measurement of viscoelastic frequency spectrum based on the fast fourier transform of displacement to applied random forces was analyzed using spectrum analyzer. The materials was tested under two dynamic conditions. One was a static load of 10.0N and a dynamic peak load of 3.0N. Second was a static load of 20.0N and a dynamic peak load of 5.0N. The dynamic stiffness of the porcelain specimens measured under each condition was significantly (P

OSSEOINTEGRATED TITANIUM PLASMA COATED IMPLANTS IN RECONSTRUCTION OF EDENTULOUS MANDIBLE

Fifteen patients underwent surgical insertion of titanium plasma sprayed screws in the mandible ridge over the symphysis region. In 3 patients, along with the screws in the symphysis region, hollow basket implant type 'H', one each in the mandible first/second molar region were inserted. Implants were fixed only in those patients who had retention and stability problems of mandibular artificial denture. Indication, technique and biocompatibility of titanium implants and tissue supported over denture have been discussed.

BI‐CYCLICAL INSTRUMENT FOR ASSESSING TEXTURE PROFILE PARAMETERS AND ITS RELATIONSHIP TO SENSORY EVALUATION OF TEXTURE

ABSTRACTThe most popular instrumental imitative test is the Texture Profile Analysis (T.P.A.). It was originated in the General Foods Laboratories (Szczesniak et al. 1963) and adapted to the Instron by Bourne (1978). T.P.A. involves a double compression test that uses flat plates attached to an Instron Universal Testing Machine (I.U.T.M.). Several instrumental parameters can be extracted from the force/deformation curve generated by the test (e.g. hardness, cohesiveness, springiness, and chewiness). Recently developed in our laboratory, the Bi‐cyclical Instrument for Texture Evaluation (B.I.T.E. master) uses the I.U.T.M. to generate its motion and features a set of artificial dentures as well as a tri‐dimensional movement simulating a chewing motion. Five parameters were extracted from the force/deformation curve to evaluate their potential use for the prediction of cohesiveness.

接着性レジン オリンパス・キャスタブル・セラミックス（ＯＣＣ）の接着

SiO2 type glass ceramics (OCC), which educe mica and -spodiumen crystals, were developed in the 1980 s and clinically applied in 1986. On a commercial basis, some of the clinical failure cases developed, and since 1995, properties of the material and technique have been reexamined. OCC restorations are now cemented by Panavia 21, a luting agent.Some of the main improvements of OCC to prevent failure are as follows: Currently used pellet type was changed to powder type and stabilization of the material was attempted. In the laboratory technique, polishing of OCC restorations, which has been done after ceraming, was done before ceraming, in the state of as-cast because processed micro cracks became obtuse angles or diminished. The crystalization schedule was examined, and a modified schedule was found to be useful for obtaining small, constant sized crystal grains.Furthermore, applications of OCC to the artificial denture teeth or implant prosthesis and so on were discussed.

Denture tooth selection: Size matching of natural anterior tooth width with artificial denture teeth

This project, conducted by the Removable Prosthodontic faculty, compared the mesiodistal widths of the six maxillary anterior teeth with the widths of denture teeth from six different denture tooth manufacturers. Four hundred eighty-eight casts of dental students were measured from the distal aspect of each canine across the facial surfaces of the six anterior teeth with a flexible plastic millimeter rule. Denture teeth from six manufacturers were compared (370 molds). The results indicated that denture teeth are predominantly smaller and natural teeth are larger.

Comparison of Anterior Tooth Width in Natural and Artificial Dentitions

Purpose This study characterizes the distribution of the mesiodistal widths of maxillary anterior natural teeth for comparison with the widths of the most commonly used artificial denture teeth. Materials and Methods The width of the six maxillary anterior teeth was measured on a curve defined by the facial surfaces of the teeth. Four hundred fifty-one casts of completed orthodontic patients (154 men and 297 women) were measured separately by gender. The width of the maxillary anterior natural teeth was compared to that of artificial denture teeth (Bioblend, Dentsply International, York, PA). Results The mean ± standard deviation (SD) width of the six anterior teeth for men and women (55.6 ± 3.1 mm and 53.6 ± 3.0 mm, respectively) differed significantly (P < .05). The mode (most frequent size) was 55 mm for both men and women; however, 40% of the women and 67% of men had anterior teeth that measured 55 mm or wider. In contrast, the mean width of the most widely distributed artificial maxillary denture teeth (Bioblend) is 50.1 mm, with a range of 44 to 58 mm. Of the 42 molds available, only 5 have a width of 55 mm or greater. Conclusions These findings suggest that one reason for the inappropriate selection of comparatively small maxillary denture teeth is the lack of physiologically sized tooth molds.

Wear of artificial denture teeth by use of toothbrushes. Part 1: abrasive wear of anterior teeth.

High-strength denture teeth (HS teeth) were developed in order to improve the hardness and wear resistance of conventional plastic denture teeth (PL teeth), while retaining their feature of easy occlusal adjustment. The objective of this study was to evaluate the abrasive wear resistance of HS teeth. We conducted wear tests and measured surface roughness using six types of anterior artificial teeth, i.e., three types of HS teeth and three types of PL teeth, the latter serving as the control. The results of the toothbrush abrasion test revealed that the HS teeth had about 5 times greater wear resistance than the PL teeth. It was also found that the type of artificial teeth and the number of abrasive wear-testing strokes had a significant (P less than 0.05) influence on the surface roughness of artificial teeth.