Bollettino della Società italiana di biologia sperimentale
The behavior of two enzymes of the ornithine pathway, leading to the formation of proline and, ev... more The behavior of two enzymes of the ornithine pathway, leading to the formation of proline and, eventually, of collagen, arginase and ornithine oxo-acid aminotransferase has been investigated in normal and inflamed gingival tissue. Both enzymatic activities show a statistically significant decrease in pathological samples as compared to normal ones. The data on arginase activity may be in agreement with the already documented low level of urea in pathological gingival fluid, while a decrease of the ornithine aminotransferase activity could be linked to the phenomenon of gingival retraction, i.e. the lack of complete regeneration of gingival tissue usually observed in chronically inflamed subjects, that would be reasonably parallel to a decreased proline/collagen synthesis.
A statistical survey has been carried out on the incidence of caries in the population of Sardini... more A statistical survey has been carried out on the incidence of caries in the population of Sardinia. It is shown that the DMF index has grown steadily from 2.6 among the young (0-12 year old) to 13.07 in the group aged between 20.1 and 30. The socioeconomic changes of the past thirty years in Sardinia are looked at in an attempt to explain this phenomenon.
Bollettino della Società italiana di biologia sperimentale
These experiments were aimed at clarifying the spinal-masseteric connections by observing the eff... more These experiments were aimed at clarifying the spinal-masseteric connections by observing the effect of electrical stimulation of radial nerve afferents on masseter muscle activity. Spontaneous and evoked electrical responses of the masseter motor units were recorded with tungsten microelectrodes and analysed on computer. Results show that electrical stimulation of both radial nerves induces responses in single masseter motor units. The response patterns were characterized most frequently by excitation, but also by a sequence of excitation inhibition. The latency in masseter muscle responses were found to be lower in contralateral recordings: 18.26 +/- 4.04 msec (x +/- SD) compared with a latency of 24.3 +/- 5.25 msec in ipsilateral recordings. These observations confirm the hypothesis that somatosensory impulses eminating from the radial nerve participate in the postural control of the masseter muscle aimed at maintaining correct jaw position during forelimb displacement.
Obiettivi: scopo del lavoro è lo studio morfologico al TEM e SEM dell'inter-diffusione sullo ... more Obiettivi: scopo del lavoro è lo studio morfologico al TEM e SEM dell'inter-diffusione sullo smalto di tre diversi si-stemi adesivi. Quali parametri analitici sono stati valutati la profondità di in-filtrazione, la presenza di resin tag-like e di ramificazioni laterali. Materiali e Metodi: per la sperimenta-zione sono stati utilizzati quindici pre-molari suddivisi in tre gruppi di cinque elementi ciascuno in cui sono stati ap-plicati i seguenti sistemi: Gruppo 1: XP Bond, etch&rinse adhesive system (Dent-sply, Konstanz, Germany); Gruppo 2: Clearfil SE Bond, two step self-etching sy-stem, (Kuraray Co. Osaka, Japan); Grup-po 3: Clearfil S3 Bond, one step self-etching system (Kuraray Co. Osaka, Japan). I campioni così allestiti sono stati prepa-rati per l'osservazione al SEM e TEM. La valutazione dei micro resin tag-like è sta-ta effettuata assegnando un punteggio qualitativo ad ogni sistema adesivo. L'a-nalisi statistica dell'interdiffusione me-dia è stata eseguita con...
The purpose of this study is the evaluation of the tooth eruption ages in a sample of children ag... more The purpose of this study is the evaluation of the tooth eruption ages in a sample of children aged between 6 and 24 months. The sample consists of 204 children aged between six and twenty-four months, followed up for a period of one year in collaboration with seven pediatricians in the province of Sassari (Italy). The visits were carried out at the paediatricians' practice in order to receive immediate feedback about the clinical conditions of children. Regarding the ages of eruption of all elements it was observed a shift more or less important, depending on the tooth considered.
Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spat... more Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spatio-temporal variations in the center of body pressure and evaluates the mechanisms of maintenance of balance. The study used a stabilimetric platform to evaluate posture changes in patients with cranio-cervico-mandibular disorders before and after treatment for malocclusion. Between February 1998 and December 2000, 60 patients with cranio-cervico-mandibular disorders were recruited from the Dentistry Clinic of the University of Sassari. Each patient underwent two stabilimetric examinations (closed mouth with cotton wads inserted between the dental arches). The tests were conducted on a stabilimetric platform. Measurement of body posture load and sway were analyzed with a specific software program that correlated the vestibular, somatosensory and visual systems, and determined the role of each in postural control. The stabilimetric analysis showed that the adoption of the plaque allowed r...
Experiments performed in the guinea pig were aimed at evaluating the effect of electric or calori... more Experiments performed in the guinea pig were aimed at evaluating the effect of electric or caloric stimulations of the vestibular afferents on the electrical activity of the jaw-closing and jaw-opening trigeminal motoneurons. Results showed that masseter and digastric motoneurons mainly responded to vestibular ampullar activation with excitatory responses, with latencies being shorter for contralateral than ipsilateral ampullar stimulation. Differences in latencies between the jaw-closing and jaw-opening trigeminal motoneurons were observed: the masseter motoneurons constantly responded about 2 msec earlier than the digastric motoneurons. These results suggest that the vestibular-trigeminal relationship is quite complex and uses multiple systems to connect the vestibular apparatus with the trigeminal motor nuclei. From the functional point of view, the vestibular-trigeminal relationship may play a role in the dynamic control of the jaw muscle tone during head movements.
The purpose of the present study is to investigate the relationship between dental occlusion and ... more The purpose of the present study is to investigate the relationship between dental occlusion and physical performance using the Ergo-jump platform, and to highlight connections, if any. For the purpose of this research, 30 patients suffering from cervico-facial pathology and 10 without temporomandibular joint dysfunction were selected from within the Dental Clinic of the University of Sassari. For the first group a resin plate was prepared to correct the malocclusion, while for the control group a bite was prepared that created it. Subjects carried out exercises with the Ergo-jump platform, a device that assesses physical capabilities and athletic performance. Patients were asked to do 2 exercises, a counter movement jump and a mechanical power test, with plate and without plate. The tests of the first group were as follows: flying times with the bite were 0.01 s longer; the average elevation in the counter movement jump test did not give statistically significant results; execution...
The purpose of the present paper is to carry out an SEM investigation into the adhesive cementati... more The purpose of the present paper is to carry out an SEM investigation into the adhesive cementation of quartz fibre posts in canals treated with endodontic cements containing or not containing eugenol. Sixteen selected tooth roots were subdivided into 4 groups and prepared with the step-back technique. Group A, without canal filling and with a cemented post, was the control group; in groups B and C, the canals were closed with guttapercha, endomethasone C and eugenol, those of group D with guttapercha and AH Plus without eugenol. The canals were prepared so as to be able to take D.T. light-posts irrigated with water (group C with ethyl alcohol) mordanted with orthophosphoric acid after applying 2 layers of photopolymerised ONE-STEP; 2 layers of ONE-STEP were applied to the post. DUO-LINK cement was positioned in the canal after inserting the post, removing excess resin and photopolymerising. The samples were prepared for SEM observation. Group A: the apical portion shows the post ab...
The aim of this study was to evaluate the relationship between craniomandibular disorders and pos... more The aim of this study was to evaluate the relationship between craniomandibular disorders and postural alterations using baropodometric examination. All tests were carried out in the Department of Dentistry at Sassari University in a population of patients with cranio-cervico-mandibular disorders (CCMD) of various types and severity. A total of 10 subjects (mean age approximately 30 years) with this pathology were evaluated over 7 months. All patients were treated using the following protocol: objective functional and clinical examination, radiographic tests, occlusal treatment using acrylic resin plate, baropodometric test with static and dynamic posture assessment, with eyes open and closed, before and after treatment with orthesis. An improved postural position was observed in 80% of cases, of which 30% showed an improvement in both static and dynamic posture, 20% only in static and 30% only in dynamic; these results highlighted the importance of baropodometric analysis in the co...
Experimental data report that vestibular afferents affect trigeminal system activity. The aim of ... more Experimental data report that vestibular afferents affect trigeminal system activity. The aim of this work was to evaluate whether static vestibular stimulation affects the excitability of trigeminal motoneurons in man. In order to assess this, voluntary EMG activity of masseter muscles as well as duration and latency of the early and late components of EMG exteroceptive silent period were evaluated while keeping the subject in vertical position and during 20 degrees static tilt. The experiments were performed on ten adult subjects with no orofacial, neurologic and otologic disorders. Each subject sat on a chair, which kept the complex head-jaw-neck-trunk and the limbs securely fixed, in order to minimize any interference due to the activation of somatosensory and proprioceptive afferents from these districts. The subjects were instructed to contract masseter muscles at 25% of their maximum bite force and the isometric force monitoring was used as visual feedback. Exteroceptive sile...
Experiments were carried out on anaesthetized guinea pigs to evaluate whether vestibular and soma... more Experiments were carried out on anaesthetized guinea pigs to evaluate whether vestibular and somatosensory informations converge upon the same trigeminal motoneurones and, if so, how they interact in the modulation of their activity. It was found that excitatory responses occurred in these motoneurones when an appropriate electrical stimulation was applied to the common radial nerve. The same was true if the electrical stimulus was applied to the vestibular ampullae. In another set of experiments the stimulation was applied both to the vestibular ampullae and to the common radial nerve at various time-intervals. The amplitude of the motoneuronal responses to common radial nerve stimulation was reduced when preceded by a vestibular stimulation. The same was true when the sequence of stimulations was reversed: in this case there was a decrease in amplitude of the testing response to vestibular stimulation. The degree of these reductions depended upon the time-interval elapsed between ...
Bollettino della Società italiana di biologia sperimentale
Mechanical stimulation of the ipsilateral incisor tooth in the rat evoked reflex discharges in th... more Mechanical stimulation of the ipsilateral incisor tooth in the rat evoked reflex discharges in the hypoglossal nerve branch innervating the intrinsic and extrinsic tongue muscles. Stimulation elicited biphasic potentials in the whole XIIth nerve and influenced the unitary firing rate in 54 out of 80 fibers tested. The fiber responses were characterized by excitation or inhibition in frequency discharge or sequences of excitation-inhibition or inhibition-excitation. The results observed suggest that the periodontal-hypoglossal reflexes play a role in the control of tongue position during mastication.
Bollettino della Società italiana di biologia sperimentale
The behavior of two enzymes of the ornithine pathway, leading to the formation of proline and, ev... more The behavior of two enzymes of the ornithine pathway, leading to the formation of proline and, eventually, of collagen, arginase and ornithine oxo-acid aminotransferase has been investigated in normal and inflamed gingival tissue. Both enzymatic activities show a statistically significant decrease in pathological samples as compared to normal ones. The data on arginase activity may be in agreement with the already documented low level of urea in pathological gingival fluid, while a decrease of the ornithine aminotransferase activity could be linked to the phenomenon of gingival retraction, i.e. the lack of complete regeneration of gingival tissue usually observed in chronically inflamed subjects, that would be reasonably parallel to a decreased proline/collagen synthesis.
A statistical survey has been carried out on the incidence of caries in the population of Sardini... more A statistical survey has been carried out on the incidence of caries in the population of Sardinia. It is shown that the DMF index has grown steadily from 2.6 among the young (0-12 year old) to 13.07 in the group aged between 20.1 and 30. The socioeconomic changes of the past thirty years in Sardinia are looked at in an attempt to explain this phenomenon.
Bollettino della Società italiana di biologia sperimentale
These experiments were aimed at clarifying the spinal-masseteric connections by observing the eff... more These experiments were aimed at clarifying the spinal-masseteric connections by observing the effect of electrical stimulation of radial nerve afferents on masseter muscle activity. Spontaneous and evoked electrical responses of the masseter motor units were recorded with tungsten microelectrodes and analysed on computer. Results show that electrical stimulation of both radial nerves induces responses in single masseter motor units. The response patterns were characterized most frequently by excitation, but also by a sequence of excitation inhibition. The latency in masseter muscle responses were found to be lower in contralateral recordings: 18.26 +/- 4.04 msec (x +/- SD) compared with a latency of 24.3 +/- 5.25 msec in ipsilateral recordings. These observations confirm the hypothesis that somatosensory impulses eminating from the radial nerve participate in the postural control of the masseter muscle aimed at maintaining correct jaw position during forelimb displacement.
Obiettivi: scopo del lavoro è lo studio morfologico al TEM e SEM dell'inter-diffusione sullo ... more Obiettivi: scopo del lavoro è lo studio morfologico al TEM e SEM dell'inter-diffusione sullo smalto di tre diversi si-stemi adesivi. Quali parametri analitici sono stati valutati la profondità di in-filtrazione, la presenza di resin tag-like e di ramificazioni laterali. Materiali e Metodi: per la sperimenta-zione sono stati utilizzati quindici pre-molari suddivisi in tre gruppi di cinque elementi ciascuno in cui sono stati ap-plicati i seguenti sistemi: Gruppo 1: XP Bond, etch&rinse adhesive system (Dent-sply, Konstanz, Germany); Gruppo 2: Clearfil SE Bond, two step self-etching sy-stem, (Kuraray Co. Osaka, Japan); Grup-po 3: Clearfil S3 Bond, one step self-etching system (Kuraray Co. Osaka, Japan). I campioni così allestiti sono stati prepa-rati per l'osservazione al SEM e TEM. La valutazione dei micro resin tag-like è sta-ta effettuata assegnando un punteggio qualitativo ad ogni sistema adesivo. L'a-nalisi statistica dell'interdiffusione me-dia è stata eseguita con...
The purpose of this study is the evaluation of the tooth eruption ages in a sample of children ag... more The purpose of this study is the evaluation of the tooth eruption ages in a sample of children aged between 6 and 24 months. The sample consists of 204 children aged between six and twenty-four months, followed up for a period of one year in collaboration with seven pediatricians in the province of Sassari (Italy). The visits were carried out at the paediatricians' practice in order to receive immediate feedback about the clinical conditions of children. Regarding the ages of eruption of all elements it was observed a shift more or less important, depending on the tooth considered.
Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spat... more Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spatio-temporal variations in the center of body pressure and evaluates the mechanisms of maintenance of balance. The study used a stabilimetric platform to evaluate posture changes in patients with cranio-cervico-mandibular disorders before and after treatment for malocclusion. Between February 1998 and December 2000, 60 patients with cranio-cervico-mandibular disorders were recruited from the Dentistry Clinic of the University of Sassari. Each patient underwent two stabilimetric examinations (closed mouth with cotton wads inserted between the dental arches). The tests were conducted on a stabilimetric platform. Measurement of body posture load and sway were analyzed with a specific software program that correlated the vestibular, somatosensory and visual systems, and determined the role of each in postural control. The stabilimetric analysis showed that the adoption of the plaque allowed r...
Experiments performed in the guinea pig were aimed at evaluating the effect of electric or calori... more Experiments performed in the guinea pig were aimed at evaluating the effect of electric or caloric stimulations of the vestibular afferents on the electrical activity of the jaw-closing and jaw-opening trigeminal motoneurons. Results showed that masseter and digastric motoneurons mainly responded to vestibular ampullar activation with excitatory responses, with latencies being shorter for contralateral than ipsilateral ampullar stimulation. Differences in latencies between the jaw-closing and jaw-opening trigeminal motoneurons were observed: the masseter motoneurons constantly responded about 2 msec earlier than the digastric motoneurons. These results suggest that the vestibular-trigeminal relationship is quite complex and uses multiple systems to connect the vestibular apparatus with the trigeminal motor nuclei. From the functional point of view, the vestibular-trigeminal relationship may play a role in the dynamic control of the jaw muscle tone during head movements.
The purpose of the present study is to investigate the relationship between dental occlusion and ... more The purpose of the present study is to investigate the relationship between dental occlusion and physical performance using the Ergo-jump platform, and to highlight connections, if any. For the purpose of this research, 30 patients suffering from cervico-facial pathology and 10 without temporomandibular joint dysfunction were selected from within the Dental Clinic of the University of Sassari. For the first group a resin plate was prepared to correct the malocclusion, while for the control group a bite was prepared that created it. Subjects carried out exercises with the Ergo-jump platform, a device that assesses physical capabilities and athletic performance. Patients were asked to do 2 exercises, a counter movement jump and a mechanical power test, with plate and without plate. The tests of the first group were as follows: flying times with the bite were 0.01 s longer; the average elevation in the counter movement jump test did not give statistically significant results; execution...
The purpose of the present paper is to carry out an SEM investigation into the adhesive cementati... more The purpose of the present paper is to carry out an SEM investigation into the adhesive cementation of quartz fibre posts in canals treated with endodontic cements containing or not containing eugenol. Sixteen selected tooth roots were subdivided into 4 groups and prepared with the step-back technique. Group A, without canal filling and with a cemented post, was the control group; in groups B and C, the canals were closed with guttapercha, endomethasone C and eugenol, those of group D with guttapercha and AH Plus without eugenol. The canals were prepared so as to be able to take D.T. light-posts irrigated with water (group C with ethyl alcohol) mordanted with orthophosphoric acid after applying 2 layers of photopolymerised ONE-STEP; 2 layers of ONE-STEP were applied to the post. DUO-LINK cement was positioned in the canal after inserting the post, removing excess resin and photopolymerising. The samples were prepared for SEM observation. Group A: the apical portion shows the post ab...
The aim of this study was to evaluate the relationship between craniomandibular disorders and pos... more The aim of this study was to evaluate the relationship between craniomandibular disorders and postural alterations using baropodometric examination. All tests were carried out in the Department of Dentistry at Sassari University in a population of patients with cranio-cervico-mandibular disorders (CCMD) of various types and severity. A total of 10 subjects (mean age approximately 30 years) with this pathology were evaluated over 7 months. All patients were treated using the following protocol: objective functional and clinical examination, radiographic tests, occlusal treatment using acrylic resin plate, baropodometric test with static and dynamic posture assessment, with eyes open and closed, before and after treatment with orthesis. An improved postural position was observed in 80% of cases, of which 30% showed an improvement in both static and dynamic posture, 20% only in static and 30% only in dynamic; these results highlighted the importance of baropodometric analysis in the co...
Experimental data report that vestibular afferents affect trigeminal system activity. The aim of ... more Experimental data report that vestibular afferents affect trigeminal system activity. The aim of this work was to evaluate whether static vestibular stimulation affects the excitability of trigeminal motoneurons in man. In order to assess this, voluntary EMG activity of masseter muscles as well as duration and latency of the early and late components of EMG exteroceptive silent period were evaluated while keeping the subject in vertical position and during 20 degrees static tilt. The experiments were performed on ten adult subjects with no orofacial, neurologic and otologic disorders. Each subject sat on a chair, which kept the complex head-jaw-neck-trunk and the limbs securely fixed, in order to minimize any interference due to the activation of somatosensory and proprioceptive afferents from these districts. The subjects were instructed to contract masseter muscles at 25% of their maximum bite force and the isometric force monitoring was used as visual feedback. Exteroceptive sile...
Experiments were carried out on anaesthetized guinea pigs to evaluate whether vestibular and soma... more Experiments were carried out on anaesthetized guinea pigs to evaluate whether vestibular and somatosensory informations converge upon the same trigeminal motoneurones and, if so, how they interact in the modulation of their activity. It was found that excitatory responses occurred in these motoneurones when an appropriate electrical stimulation was applied to the common radial nerve. The same was true if the electrical stimulus was applied to the vestibular ampullae. In another set of experiments the stimulation was applied both to the vestibular ampullae and to the common radial nerve at various time-intervals. The amplitude of the motoneuronal responses to common radial nerve stimulation was reduced when preceded by a vestibular stimulation. The same was true when the sequence of stimulations was reversed: in this case there was a decrease in amplitude of the testing response to vestibular stimulation. The degree of these reductions depended upon the time-interval elapsed between ...
Bollettino della Società italiana di biologia sperimentale
Mechanical stimulation of the ipsilateral incisor tooth in the rat evoked reflex discharges in th... more Mechanical stimulation of the ipsilateral incisor tooth in the rat evoked reflex discharges in the hypoglossal nerve branch innervating the intrinsic and extrinsic tongue muscles. Stimulation elicited biphasic potentials in the whole XIIth nerve and influenced the unitary firing rate in 54 out of 80 fibers tested. The fiber responses were characterized by excitation or inhibition in frequency discharge or sequences of excitation-inhibition or inhibition-excitation. The results observed suggest that the periodontal-hypoglossal reflexes play a role in the control of tongue position during mastication.
Uploads
Papers by Giacomo Chessa