Biomedical subjects
Publications and source records attributed to R G Jagger.
A case of progressive osteolysis of the mandibular condyles in a 55-year-old female patient with systemic sclerosis (SSc) is described. Orofacial involvement and radiological manifestations of SSc are discussed.
The literature with respect to whether or not psychiatric disorders represent a contraindication to dental implant treatment is sparse and contradictory. This paper describes three cases in which patients with psychiatric disorders were provided with dental implant retained prostheses. It is concluded that mental health disorders are not necessarily a contraindication to dental implant treatment and dental implant treatment can provide valuable psychological support. If any doubt exists about the effect of a psychiatric disorder on the prognosis of implant treatment the opinion of a psychiatrist should be obtained. The development of liaison psychiatry for dental hospitals should be seen as an ideal.
The term 'phantom bite' is used to describe an uncommon condition in which patients are preoccupied with their dental occlusion, believing that it is abnormal. The condition is remarkable for the nature of the involved explanations and interpretations that the patients give and for their persistence in trying to find a solution to what appears to be a relatively minor problem. Three clinical cases that illustrate the nature of this condition are presented and problems associated with the management of affected patients are discussed. Phantom bite can be a disabling disorder which is difficult to treat. Available evidence suggests that the symptoms cannot be improved by occlusal treatments. It is therefore essential to avoid extensive irreversible restorative treatment. General dental practitioners should refer patients for specialist opinion and management. Psychiatric assessment with recommendations for management should be obtained if possible. The prognosis is poor for symptom elimination but need not necessarily be poor for patients' overall functioning and well-being. It is suggested that emphasis should be placed on building adaptive coping skills. Further research is needed to elucidate the nature of the condition to improve treatment.
The purpose of this study was to determine the prevalence of signs and symptoms of temporomandibular disorders (TMD) in indigenous South American Indians. A total of 140 consecutive indigenous Indians (69 Quechua and 71 Colorado) attending a mobile dental health caravan in the Santo Domingo region of Ecuador were examined objectively and subjectively for signs and symptoms of TMD using a method similar to that used in previous studies. There was a prevalence of up to 41% of at least one symptom. The Quechua Indians reported a significantly higher prevalence of difficulty in opening of the mouth and pain in front of the ears than the Colorado Indians. There was a prevalence of up to 63% of at least one sign. The objective findings in the Colorado Indians were similar to those found to be present in a Scandinavian population and an Arab population in previous studies using similar methods. Signs and symptoms of TMD are common in Latin American Indians. Differences occur between different populations in the same geographical area.
Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dental appliances such as stents, occlusal splints and baseplates for occlusal rims. The purpose of the present study was to measure the accuracy of adaptation of Perspex PMMA sheet and to determine the effect of annealing on the accuracy of the thermoformed specimens. The results of the study showed that PMMA can produce specimens that are accurately adapted to the cast. Immersion in water resulted in an increase in the space between the cast and the specimen for both thermoformed and thermoformed and annealed acrylic resin. Annealing of the thermoformed specimens had significantly less increase in space between the cast and the specimens when immersed in water over a period of 3 months.
The present study investigated the effectiveness of an intra-oral mandibular advancement device in the treatment of patients with obstructive sleep apnoea (OSA) who could not tolerate or who had failed to comply with continuous positive airway pressure (CPAP). Thirty-five patients diagnosed by sleep study as suffering from OSA, who had either been unable to tolerate or had been non-compliant with CPAP treatment, were included in the study. The subjects completed an Epworth sleep questionnaire. The subjects then had an oral appliance made. After using the appliance for 3 months, the patients repeated the questionnaires and had a repeat sleep study performed with the oral appliance in situ. Thirty-one subjects completed the investigation. Mean AHI pre- and post-study were 26.64 and 24.06, respectively (P > 0.05). Mean Epworth scores pre- and post-study were 16.32 and 14.64, respectively (P > 0.05). Those patients with a pre-study AHI < 20 (n = 23), however, did significantly better with the appliance (P < 0.0001). Those patients with a pre-study AHI > 20 did not benefit from this device (P > 0.05). The main problems encountered were initial jaw discomfort in 18 patients and dry mouth in 11 patients (both of which improved with continued usage). It was concluded that the type of appliance used in this study can be recommended for those with mild OSA who are unable to tolerate CPAP.
A range of materials, often marketed as high strength resins is available. These materials are often expensive options to conventional heat-cured acrylic resin. The aim of this study was to investigate transverse and impact strength of five "high strength" acrylic resin denture base materials. A conventional heat-cured acrylic resin was used as a control. Specimens were prepared as specified in the International Standard Organization (ISO 1567: 1988) and British standards for the Testing of Denture Base Resins (BS 2487: 1989) and the British Standard Specification for Orthodontic resins (BS 6747: 1987) for transverse bend and impact testing. The impact strength was measured using a Zwick pendulum impact tester and the transverse bend strength measured using a Lloyds Instruments testing machine. The results showed that Metrocryl Hi, Luctitone 199 and N.D.S. Hi all had an impact strength which was significantly higher than the control. For the modulus of rupture, there was a significant difference between Sledgehammer and the other groups. There was no significant difference between the other groups and the control. For the modulus of elasticity, Sledgehammer produced the highest value followed by the control. The remaining four materials had a modulus of elasticity less than the control.
Explore the source record for details and available documents.
INTRODUCTION: The literature reports that the treatment of fully edentulous mandibles with implant-retained overdentures has become a recognised form of therapy: however long-term data on the success are limited. The aim of the present study was to describe the clinical effectiveness of mandibular implant-supported/retained overdentures in the management of a group of edentulous patients. MATERIALS AND METHODS: The study group consisted of 59 consecutive edentulous patients attending the clinic of prosthetic dentistry at Cardiff Dental Hospital, who had been provided with implants in the mandible for complete overdenture retention. Several clinical parameters were examined in each patient: mobility of each implant, probing pocket depth, the presence or absence of plaque and calculus on each implant, bleeding index, marginal bone loss, jaw bone quality and quantity, complications that had occurred with the implants and patients opinions of the treatment. DISCUSSION: Of implants placed, 97% remained in function. Three fixtures had been lost. There was a high frequency of bleeding on probing. Complications associated with treatment included damage or looseness of abutment screws, fracture of the bar, entrapment of food beneath the overdenture and looseness of the opposing non-implant-retained complete denture. CONCLUSION: In general a very high degree of patient satisfaction with the implant-retained overdentures was recorded.
OBJECTIVE: To promote denture retention and denture comfort, denture materials should possess adequate wettability. This in vitro study investigated the wettability of nine commercially available dental materials. METHOD AND MATERIALS: Four denture base materials, two denture hard lining materials, and three denture soft lining materials (with and without varnish treatment) were tested. The wettability measurements were made using the dynamic contact angle analysis technique. The equilibrium and hysteresis angles obtained were used for the comparisons. RESULTS: The equilibrium contact angle (thetae) ranged from 63.9 (Permaflex + varnish) to 81.0 degrees (Mollosil + varnish). The differences observed among the materials tested were statistically significant. The contact angle hysteresis ranged from 16.0 (SR 3/60 Triplex) to 51.2 degrees (Mollosil), and there was a statistically significant difference among the materials. CONCLUSION: The heat-polymerized soft lining materials exhibited the greatest equilibrium contact angle, the autopolymerized soft liner had the lowest value, and the denture base materials had intermediate values. The soft liners showed greater contact angle hysteresis than all other materials. The use of varnish altered the wetting characteristics.
STATEMENT OF PROBLEM: Maxillofacial prosthetic materials that contact skin or mucosa should have good wettability. A material that is easily wetted will form a superior lubricating layer between the supporting tissues and, thus, reduce friction and patient discomfort. The surface energy of a maxillofacial prosthetic material will give an indication of the amount of energy available for adhesion and of the susceptibility of the material to bacterial adhesion. PURPOSE: This study evaluated the wettability and surface energies of a range of commercially available silicone rubber maxillofacial prosthetic materials. MATERIAL AND METHODS: Contact angles and surface energies were measured by using a dynamic contact angle measuring technique. Four commonly used silicone maxillofacial materials were tested and their properties compared with those of an acrylic resin denture base material and a widely used denture soft lining material. RESULTS: There were no significant differences in the wettability of the silicone rubber materials. All materials were significantly less wetted than the denture acrylic resin material. There were no significant differences in the surface energies of the silicone rubber materials, but all were significantly lower than denture acrylic resin material. CONCLUSIONS: The Cahn dynamic contact angle analyzer was a quick and reproducible method for determining the contact angles and surface energies of maxillofacial materials. Further work is needed to improve the wettability of silicone rubber materials used for maxillofacial prostheses, thus, reducing their potential to produce friction with tissues.
OBJECTIVES: The objective of the present study was to evaluate the mechanical properties of an experimental formulation (Exp. 1) in order to assess its potential as a denture soft lining material. The same properties of a popular commercially available denture soft lining material (Molloplast-B) were determined and compared with the properties of Exp. 1. METHODS: Exp. 1 specimens were obtained by curing for 24 h at room temperature after the addition of the appropriate amounts of catalyst and cross-linker. Molloplast-B specimens were obtained after curing according to the manufacturer's instructions. The properties measured in the study were hardness, tear resistance, tensile strength and the bond strength of the material to a heat-cured acrylic denture base material. RESULTS: Exp. 1 had a significantly greater tensile strength, percent elongation, tear resistance and peel strength (p < 0.0001) than Molloplast-B. There was no significant difference in the hardness values of the two materials, although Molloplast-B had a significantly higher tensile bond and shear bond strength (p < 0.05). CONCLUSIONS: It was concluded that there was no significant difference in the hardness of Exp. 1 and Molloplast-B. Exp. 1 had superior tensile and tear properties. Its peel bond strength was superior to that of Molloplast-B, although its tensile bond strength and shear bond strength were less.
Scuba diving is one of the fastest growing sports in the world. It is inevitable that the general dental practitioner (GDP) will have patients who participate in this sport and they should be aware of a number of problems that a diver can experience that are associated with the teeth and related structures. The aim of this article is to introduce the GDP to the dental problems associated with diving and make recommendations on dental care for scuba divers.
STATEMENT OF PROBLEM: Colonization of denture soft lining materials by Candida albicans can result in clinical problems. Two experimental silicone soft lining materials have been developed and demonstrate good physical properties. PURPOSE OF STUDY: The aim of this study was to determine the extent of candidal adherence to these materials compared with a commercially available soft lining material and an acrylic resin denture base. MATERIAL AND METHODS: The experimental materials were constructed in a stainless-steel mold, and their surface energies were determined with a dynamic contact angle analyzer. The adherence of three strains of C. albicans was determined with an in vitro assay. In addition, one test strain was used to determine the effect on adherence of precoating the materials with whole saliva. RESULTS: Adhesion to all materials was strain variable, with the lowest adherence recorded for the two experimental materials. Decreased adherence was also apparent after precoating the materials with saliva. Correlation between surface energy of the material and the degree of candidal adhesion was seen for one strain, but no correlation was seen for the other two strains. CONCLUSION: Adherence of C. albicans to the two experimental silicone soft lining materials was significantly less than that for an acrylic resin denture base and a commercially available soft lining material.
The rationale for running combined clinics between orthodontics and restorative dentistry is given, together with the history of the development and experience of such a clinic at the Dental School and Hospital in Cardiff. Brief details of the organization of the combined clinic and possible future developments are also given.
The bimaxillary mouthguard provides enhanced protection for a participant in contact sports. This article describes the fabrication of a polyvinylacetate-polyethylene (PVAc-PE) bimaxillary mouthguard in which the connection of the maxillary and mandibular components is reinforced by pressure thermoforming a 2-mm PVAc-PE sheet over the labial and buccal portions of the mouthguard.