- Email: [email protected]
Adverse effects of mandibular protruding device
Restorative Dentistry Plastic stock tray distortion with high-viscosity impression materials Background.—Impression trays can be either custom trays made specifically for a patient or stock trays produced in various sizes by a manufacturer. Stock trays can be metal or disposable plastic. Custom trays have the advantages of providing good adhesion to the impression material, dimensional stability, an even thickness of impression material, and sufficient rigidity to resist deformation. With stock trays, a high-viscosity material is generally chosen because it can compensate for the added volume of impression material needed. With very-high-viscosity materials, flow is poor and pressure can build up during seating of the filled impression tray, possibly distorting an insufficiently rigid disposable plastic tray. Six commercially available disposable plastic stock trays and 1 commercially available metal stock tray were compared for the occurrence of dimensional changes either cross-sectionally or in arch width. Methods.—The trays were measured while empty before the impression material was inserted, on seating the impression material in a simulated arch, and on removal of the polymerized impression from the arch. Seventy specimens were tested, with 10 obtained with the use of metal stock trays and 60 with the 6 plastic trays. The expectation was that disposable plastic stock trays would be able to resist flexure as well as the metal stock tray. Results.—The disposable plastic stock trays were not able to resist deformation by the very-high-viscosity putty material and showed significant amounts of deformation. The cross-arch and cross-sectional arch dimension changes were less with the metal stock trays than the plastic trays.
Deformation in the cross-arch and the cross-sectional arch dimensions were both significantly associated with tray material. Discussion.—The metal stock tray resisted deformation when high-viscosity material was used, but the 6 disposable plastic stock trays could not. All of the plastic trays exhibited significant dimensional changes when they were removed from the simulated dental arch. The use of disposable plastic stock trays with a high-viscosity impression material should be discouraged.
Clinical Significance.—Tray selection, as well as impression material, affects impression accuracy. Putty-type silicone impression materials, due to their high viscosity, can distort flimsy impression trays. In this study, 6 different stock plastic, disposable trays, when compared with a stock metal tray, showed significant change in both cross-arch and cross-sectional dimensions.
Cho GC, Chee WWL: Distortion of disposable plastic stock trays when used with putty vinyl polysiloxane impression materials. J Prosthet Dent 92:354-358, 2004 Reprints available from WWL Chee, School of Dentistry, Rm 4374, University Park, Univ of Southern California, Los Angeles, CA 900890641; fax: 213-740-1750; e-mail: [email protected]
Sleep Disorders Adverse effects of mandibular protruding device Background.—Patients with obstructive sleep apnea (OSA) or snoring can be helped by wearing an oral appliance during sleep that protrudes the mandible and eases breathing. More than 80% of OSA patients have reportedly normalized their oxygen desaturation index values, and
snorers have maintained a healthy value with the use of a mandibular protruding device (MPD). The incidence and types of adverse events produced in the masticatory system after treatment of OSA or snoring with an MPD for 2 years were evaluated.
Volume 50 • Issue 4 • 2005 257
Methods.—Forty-four middle-aged patients with OSA and 21 with snoring participated, undergoing a clinical examination and completing questionnaires covering signs and symptoms in the masticatory system. The questionnaires were administered before MPD use and 6 months and 2 years after beginning MPD use. Results.—Significant changes in the maximum range of protrusion and mouth opening were noted between baseline and the 6-month and 2-year follow-up evaluations, but the range of laterotrusion remained stable. A significant decrease in overjet and overbite occurred gradually from baseline until after 2 years of treatment. A lateral open bite developed in 9 of the 65 patients. Temporomandibular joint (TMJ) signs were present in 34% of the participants at baseline. After 2 years, pain during mandibular movements was significantly reduced and TMJ status was stable. Patients also reported a significant reduction in the frequency of headaches. Tiredness with jaw function was reported at baseline by 3 patients, after 6 months by 8 patients, and after 2 years by only 2 patients. None of the patients experienced TMJ locking several times weekly or every day or night when first examined, but 1 had TMJ locking after 6 months and another after 2 years. Only 2 patients reported having a permanent sense of an altered occlusion. Two of the patients who had a lateral open bite develop believed their occlusion was worse than at base-
line. Seven believed their occlusion had not experienced any negative effect. Discussion.—The adverse effects attending the use of an MPD for OSA or snoring were minor compared with the improved sleep and did not prevent patients from continuing to use the MPD. The signs and symptoms in the masticatory system had diminished, and the mean range of motion of the mandible increased slightly.
Clinical Significance.—Mandibular protruding devices are often effective in reducing snoring and sleep apnea, as well as improving range of motion and reducing headaches. Care must be taken, however, to monitor possible minor occlusal alterations.
Fransson AMC, Tegelberg Å, Johansson A, et al: Influence on the masticatory system in treatment of obstructive sleep apnea and snoring with a mandibular protruding device: A 2-year follow-up. Am J Orthod Dentofacial Orthop 126:687-693, 2004 Reprints available from A Fransson, Dept of Stomatognathic Physiology and Dept of Orthodontics, Postgraduate Dental Education Ctr, PO Box 1126, SE-701 11 Örebro, Sweden; e-mail: [email protected]
Temporomandibular Disorders Infrared thermography and TMJ arthralgia Background.—Among the diagnostic imaging methods used to assess joints are radiography, arthroscopy, computed tomography (CT), and magnetic resonance imaging (MRI). Clinical thermography uses instruments that can detect and record thermal patterns on the surface of the patient’s skin. Both visual and quantitative documentation is provided. Thermography can be divided into liquid crystal thermography (contact thermography) and infrared ther-
258 Dental Abstracts
mography (noncontact thermography). Infrared thermography gathers data regarding normal and abnormal function in the sensory and sympathetic nervous systems, dysfunction of the vascular system, myofascial trauma, and local inflammatory processes. The changes observed with infrared thermography reflect physiologic changes, not anatomic ones. Recent studies have evaluated the use of infrared thermography to distinguish asymptomatic subjects
Deformation in the cross-arch and the cross-sectional arch dimensions were both significantly associated with tray material. Discussion.—The metal stock tray resisted deformation when high-viscosity material was used, but the 6 disposable plastic stock trays could not. All of the plastic trays exhibited significant dimensional changes when they were removed from the simulated dental arch. The use of disposable plastic stock trays with a high-viscosity impression material should be discouraged.
Clinical Significance.—Tray selection, as well as impression material, affects impression accuracy. Putty-type silicone impression materials, due to their high viscosity, can distort flimsy impression trays. In this study, 6 different stock plastic, disposable trays, when compared with a stock metal tray, showed significant change in both cross-arch and cross-sectional dimensions.
Cho GC, Chee WWL: Distortion of disposable plastic stock trays when used with putty vinyl polysiloxane impression materials. J Prosthet Dent 92:354-358, 2004 Reprints available from WWL Chee, School of Dentistry, Rm 4374, University Park, Univ of Southern California, Los Angeles, CA 900890641; fax: 213-740-1750; e-mail: [email protected]
Sleep Disorders Adverse effects of mandibular protruding device Background.—Patients with obstructive sleep apnea (OSA) or snoring can be helped by wearing an oral appliance during sleep that protrudes the mandible and eases breathing. More than 80% of OSA patients have reportedly normalized their oxygen desaturation index values, and
snorers have maintained a healthy value with the use of a mandibular protruding device (MPD). The incidence and types of adverse events produced in the masticatory system after treatment of OSA or snoring with an MPD for 2 years were evaluated.
Volume 50 • Issue 4 • 2005 257
Methods.—Forty-four middle-aged patients with OSA and 21 with snoring participated, undergoing a clinical examination and completing questionnaires covering signs and symptoms in the masticatory system. The questionnaires were administered before MPD use and 6 months and 2 years after beginning MPD use. Results.—Significant changes in the maximum range of protrusion and mouth opening were noted between baseline and the 6-month and 2-year follow-up evaluations, but the range of laterotrusion remained stable. A significant decrease in overjet and overbite occurred gradually from baseline until after 2 years of treatment. A lateral open bite developed in 9 of the 65 patients. Temporomandibular joint (TMJ) signs were present in 34% of the participants at baseline. After 2 years, pain during mandibular movements was significantly reduced and TMJ status was stable. Patients also reported a significant reduction in the frequency of headaches. Tiredness with jaw function was reported at baseline by 3 patients, after 6 months by 8 patients, and after 2 years by only 2 patients. None of the patients experienced TMJ locking several times weekly or every day or night when first examined, but 1 had TMJ locking after 6 months and another after 2 years. Only 2 patients reported having a permanent sense of an altered occlusion. Two of the patients who had a lateral open bite develop believed their occlusion was worse than at base-
line. Seven believed their occlusion had not experienced any negative effect. Discussion.—The adverse effects attending the use of an MPD for OSA or snoring were minor compared with the improved sleep and did not prevent patients from continuing to use the MPD. The signs and symptoms in the masticatory system had diminished, and the mean range of motion of the mandible increased slightly.
Clinical Significance.—Mandibular protruding devices are often effective in reducing snoring and sleep apnea, as well as improving range of motion and reducing headaches. Care must be taken, however, to monitor possible minor occlusal alterations.
Fransson AMC, Tegelberg Å, Johansson A, et al: Influence on the masticatory system in treatment of obstructive sleep apnea and snoring with a mandibular protruding device: A 2-year follow-up. Am J Orthod Dentofacial Orthop 126:687-693, 2004 Reprints available from A Fransson, Dept of Stomatognathic Physiology and Dept of Orthodontics, Postgraduate Dental Education Ctr, PO Box 1126, SE-701 11 Örebro, Sweden; e-mail: [email protected]
Temporomandibular Disorders Infrared thermography and TMJ arthralgia Background.—Among the diagnostic imaging methods used to assess joints are radiography, arthroscopy, computed tomography (CT), and magnetic resonance imaging (MRI). Clinical thermography uses instruments that can detect and record thermal patterns on the surface of the patient’s skin. Both visual and quantitative documentation is provided. Thermography can be divided into liquid crystal thermography (contact thermography) and infrared ther-
258 Dental Abstracts
mography (noncontact thermography). Infrared thermography gathers data regarding normal and abnormal function in the sensory and sympathetic nervous systems, dysfunction of the vascular system, myofascial trauma, and local inflammatory processes. The changes observed with infrared thermography reflect physiologic changes, not anatomic ones. Recent studies have evaluated the use of infrared thermography to distinguish asymptomatic subjects