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Biomedical subjects

G Gassino

Publications and source records attributed to G Gassino.

10 recordsLinked to original sources
PubMed2005

Surface EMG of jaw-elevator muscles and chewing pattern in complete denture wearers.

The aim of this study was to investigate the adaptation process of masticatory patterns to a new complete denture in edentulous subjects. For this purpose, muscle activity and kinematic parameters of the chewing pattern were simultaneously assessed in seven patients with complete maxillary and mandibular denture. The patients were analysed (i) with the old denture, (ii) with the new denture at the delivery, (iii) after 1 month and (iv) after 3 months from the delivery of the new denture. Surface electromyographic (EMG) signals were recorded from the masseter and temporalis anterior muscles of both sides and jaw movements were tracked measuring the motion of a tiny magnet attached at the lower inter-incisor point. The subjects were asked to chew a bolus on the right and left side. At the delivery of the new denture, peak EMG amplitude of the masseter of the side of the bolus was lower than with the old denture and the masseters of the two sides showed the same intensity of EMG activity, contrary to the case with the old denture. EMG amplitude and asymmetry of the two masseter activities returned as with the old denture in 3 months. The EMG activity in the temporalis anterior was larger with the old denture than in the other conditions. The chewing cycle width and lateral excursion decreased at the delivery of the new denture and recovered after 3 months.

Adaptation, Physiological↗
PubMed2005

Cephalometric evaluation of the upper airway in patients with complete dentures.

AIM: Obstructive sleep apnea syndrome (OSAS) is a disorder characterised by repeated obstructions of the upper airway, with consequent episodes of apnea and hypopnea during sleep, snoring, and daytime sleepiness. Recently, a role of edentulism in the occurrence or in the worsening of this disorder was suspected. The aim of the study was to assess, through a cephalometric analysis, if the removal of denture induces, and where, modifications that can favour the pharynx collapse. METHODS: A total of 27 subjects with complete or partial loss of teeth and with heavy loss of the vertical dimension, were examined. The patients were submitted to radiographs of the cranium in supine position, to simulate as much as possible the night condition, with the denture in intercuspal position (ICP), and in relaxed position both with denture (D-RP) and without it (edentule-relaxed position, E-RP). The radiographs were analysed through specific measures for OSA evaluating the parameters that could be modified by the denture. RESULTS: The pharyngeal airway space (PAS) decreases, at the level of uvula, from ICP (6.7 mm) to RP (5.3 mm) (P< 0.05). The distance between the base and the tip of the tongue significatively decreased both from ICP vs E-RP (7.35 mm vs 6.87 mm; P< 0.05), both from D-RP to E-RP (7.22 mm vs 6.87 mm; P< 0.005). CONCLUSIONS: From the data obtained from the cephalometric analysis it seems that wearing denture induces modifications in the position of the tongue, of the jaw and of the pharyngeal airway space that can favour the reduction of apnea episodes.

Adult↗
PubMed2005

Relation between length of fiber post and its mechanical retention.

AIM: The aim of this paper is to verify how the length of the fiber post may influence its retention in an insertion site. METHODS: Forty double conicity posts were used: 20 were inserted in epoxy resin cubes, the other 20 were inserted in extracted teeth at 2 different depth (5 mm and 10 mm). The samples were tractioned by an Instrom machine registering the postsite detach value. The root canals were examined by SEM. Statistical evaluation was made using the t-test. RESULTS: The results of the sample with resin cubes show a direct proportionality between the insertion length and the post retention. This relation was not appreciated in the sample which used extracted teeth: the differences between the 5 mm and 10 mm insertion are not statistically significant. The extracted posts observation show that the fixing cement stays on the post. CONCLUSIONS: In ideal conditions the retention is directly proportional to the insertion length. The weakest interface of the adhesive system is the one between dentin and fixing cement.

Mechanics↗
PubMed2004

Home care maintenance protocol for ear prostheses.

Hygienic home care maintenance for patients who have received a maxillofacial prosthesis is very important in order to secure a long-term success of a facial rehabilitation. Craniofacial implant therapy requires a specific protocol to care for the peri-implant tissues and material used for the prosthesis. This article presents the maintenance and care protocol for proper follow-up management of a maxillofacial ear prosthesis. Home care methods for the prosthesis hygiene are described, including: the insertion and the disconnection of the ear prosthesis, hygiene of the bar abutments before and after postdefinitive connection to the craniofacial fixtures, washing of the device, professional follow-up.

Humans↗
PubMed2000

Cytokine production and bone remodeling in patients wearing overdentures on oral implants.

The stability of titanium dental implants is determined by osseointegration. Bone is a dynamic tissue continuously remodeled through resorption and formation, processes controlled by local cytokine production. This study investigated osseotropic cytokine expression in gingival mucosa, in the intraforamina and inferior first molar zones, during rehabilitation with implant-retained overdentures. Specimens were taken from six patients prior to placement of implants in the intraforamina bone; at connection of healing abutments; and 4, 8, and 12 months after prosthetic anchorage. Through semi-quantitative reverse-transcriptase polymerase chain-reaction, the following constitutively expressed cytokines were found at first surgical stage: interleukin-1, -6, and -8; small amounts of interleukin-11; stem cell factor; and transforming growth factor-beta1, -beta2, and -beta3. From the connection of healing abutments to 12 months after prosthetic anchorage, transforming growth factor-beta1, -beta2, and -beta3 were markedly higher than initial values. Expression of interleukin-6 and -8 decreased 8 months after prosthetic anchorage, while that of interleukin-1 increased at 12 months. In cultured gingival fibroblasts, modulation of cytokine secretion was also time-dependent. Cell culture supernatants influenced osteoclast-like multinucleated cell formation in long-term human marrow culture or osteoblast function, depending on the cytokine profile produced. These results are consistent with functional contributions of cytokines to osseointegration and minimization of posterior edentulous zone bone resorption.

Aged↗
PubMed1994

Monitoring of the discrimination threshold for interocclusal thicknesses in rehabilitated edentulous patients.

Thirty-seven white Caucasian subjects with unsatisfactory dentures were tested for interocclusal thickness discrimination threshold. New dentures were prepared and the test was repeated on days 1, 4 and 90 (from delivery). Eight patients whose situation was still unsatisfactory were given osseointegrated implant anchored dentures and the test repeated at the same intervals. Results were analysed statistically. Improved denture fit was found to increase interocclusal sensitivity. Decreased sensitivity during follow-up might indicate the need to check denture fit.

Aged↗
PubMed1992

[Psychometric and psychofunctional studies of a group of patients with craniomandibular disorders].

The base myoelectric of masticatory muscles, and their response to stressor, was studied in a group of patients affected with craniomandibular disorders (CMD) and in a control group. Patients suffering from craniomandibular disorders were affected by at least two of these three groups of symptoms: 1) articular and/or muscular pain; 2) articular noise; 3) alteration of mandibular mobility. The psychofunctional investigation was as follows: in order to measure the base myoelectric activity of the masticatory muscles and their response to stress, the Myotron 222 two-channel electromyographs were used, so as to record the activity of four muscles contemporaneously. The research was conducted on the masseter and anterior fascia of the temporal muscles, which are the most readily accessible of the elevator muscles. A non-specific stressor (shot pistol) was administered to the subjects after the base myoelectric level had been established. These factors were evaluated on the electromyograms: base activity before the stressor; the shape of the response to the stressor; the recovery time after the stressor. The minimum activity before the stressor was usually measured as the minimum activity the subject was able to maintain for roughly one minute. The psychometric investigation used "Minnesota Multiphasic Personality Inventory" (MMPI); this is a nonprojective personality test widely used in clinical psychology. The base level of myoelectric activity was higher in patients affected with craniomandibular disorders than in healthy patients, who generally had low initial values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A comparative evaluation of the increase in heat during the polymerization reaction of resins for temporary fixed dentures].

Self-curing resins enable the operator to prepare directly temporary prosthesis on single crown abutments. However such a technique may involve the danger of an inflammation of the pulp, due to the exothermic polymerization reaction of self-curing resins. The Authors suggest experimentally assessing the thermic increase during the polymerization reaction of seven different resins. Moreover they want to estimate the influence of the ratio monomer-polymer on the thermic curve of such reactions.

Composite Resins↗
PubMedDate not supplied

Non carious cervical lesions. A review.

Non-carious cervical lesions (NCCL) are characterized by a loss of hard dental tissue near the cement-enamel-junction. Commonly, their shape is like a wedge with the apex pointing inwards. Other times, they appear as regular depressions, like a dome or a cup. Their main characteristic is the presence of hard-mineralized tissue. According to the literature, the prevalence of cervical lesions is 85%, while their incidence is about 18% among permanent teeth. NCCL are currently classified as erosion, abrasion, or abfraction. Their etiology seems to be related to different factors: hexogen and endogen acids, mechanical abrasive action, tooth flexion under axial and non-axial loads. Moreover, it seems that a fundamental role is ascribable to tooth bending phenomena due to the strength components parallel or oblique to the occlusal level, which occur during the normal function as well as during parafunctions. The frequent therapeutic failures are probably due to the same factors causing the onset of the original lesion. Several materials have been proposed to restore NCCL: amalgam (abandoned), glass-ionomer cements, compomers, and composite resins. Early failures of these restorations have often been reported in the literature, probably due to the same factors which originally caused the lesions. Further investigations are required to determine more reliable restorative therapies.

Compomers↗