Fiberotomy enhances orthodontic tooth movement and diminishes relapse in a rat model.

OBJECTIVES: Accelerated orthodontic tooth movement is triggered by procedures that include mucoperiosteum flap surgery and surgical scarring of cortical bone. Our aim was to test whether fiberotomy by itself will accelerate orthodontic tooth movement and diminish relapse. MATERIALS AND METHODS: In 34 Wistar rats, alveolar bone resorption and molar tooth movement were measured after fiberotomy, apical full-thickness flap without detachment of gingiva from the roots, or no surgery. Orthodontic appliance was installed at time of surgery and activated for 14 days, generating movement of the first maxillary molar buccal and then removed. RESULTS: Percent of sections in which alveolar bone resorption was detected was significantly higher (p < 0.05) after fiberotomy (27%) in comparison with apical flap surgery (12%) or no surgery (6%), after 30 days. Also, at the end of active phase, the molar moved significantly faster (p < 0.01) and twice the distance after fiberotomy (0.54 ± 0.33) in comparison with apical surgery (0.26 ± 0.12) or no surgery (0.3 ± 0.09). Sixteen days after the appliance was removed, only 12% relapse was recorded in the fiberotomy group, while almost total relapse in other two groups. CONCLUSION: We conclude that fiberotomy solely accelerated orthodontic tooth movement and diminished relapse.

Enamel, dentine and pulp in talon primary maxillary central incisors: a histomorphometric study.

AIM: To examine whether a talon incisor has an abnormal shape due to excess of dental hard tissues or pulp. METHODS: Two bilateral primary maxillary central incisors with talon cusp and a supernumerary mesiodens were removed from a 6-year-old boy. Histologically, 7 undecalcified cross sections (70 microm) were harvested from each talon tooth and from two regular primary central incisors of another child. Microradiographs of the sections were prepared and examined for enamel width, dentin width, pulp tissue area, and crown size (mesio-distal, labio-palatal) using Image Analysis. RESULTS: No association to other developmental disorders was observed. The mean width of the enamel and dentin was similar in the talon and the regular incisors (difference 7.5% and 2.4%, respectively). The pulp area was greater in the talon teeth (37.4%). The latter had an effect on the increase in the mesio-distal and labio-palatal dimensions of the talon teeth (17.6% and 23.9%, respectively). CONCLUSIONS: The fact that the talon cusp has normal enamel and dentin layers with a substantial enlarged pulp tissue suggests that similar developmental anomalies occur during tooth morphodifferentiation as in taurodontism and dens evagintus of premolars.

Subclinical status epilepticus in a child after closed head injury.

A 14-year-old girl with closed head injury and a normal computerized tomographic scan underwent an electroencephalographic tracing that surprisingly revealed typical status epilepticus electrical activity. No episodes of motor clinical convulsions were observed from the moment of trauma throughout the admission period. Treatment with phenytoin caused a dramatic clinical improvement. Repeated electroencephalogram (EEG) 4 days later was within normal limits. Posttraumatic seizures are reported after head injury, yet, the issue of "invisible" or "subclinical" seizures associated with trauma is not discussed. In these cases EEG, (an uncommon examination in the early period after head injury) may be the only tool for proper diagnosis and treatment with anticonvulsants. This case report raises the question of the role of EEG in the unconscious patients who does not present with obvious convulsions. Clinical indications for performing EEG after head trauma without seizures are discussed.

Conservative treatment of a traumatic subdural hematoma of the posterior fossa in a child: case report.

Traumatic posterior fossa hematomas are uncommon. Subdural hematomas in this location are probably the rarest. The natural history in acute cases is one of rapid deterioration and death from brain-stem compression. Rapid surgical intervention is indicated in acute cases. We report a case of a traumatic posterior fossa subdural hematoma in a 3-year-old child treated conservatively with a good outcome.

Reversible opisthotonus following intracranial pressure changes in Chiari malformation.

A shunted myelodysplastic child with Chiari II malformation presented with shunt malfunction and opisthotonus. Correction of a distal obstruction lead to an initial improvement followed by overdrainage of cerebrospinal fluid and repetition of an opisthotonic posture. The possible mechanisms which unmask lower brainstem dysfunction in Chiari malformation when intracranial hyper- or hypotension exist, are discussed.

The effect of intracranial hypotension on cerebral blood flow in a feline model.

Intracranial hypotension is a known clinical entity but its pathophysiology has been meagerly studied. Any setting with cerebrospinal fluid leakage or drainage can cause intracranial hypotension. A feline model of kaolin induced chronic hydrocephalus with controlled cerebrospinal fluid drainage from a lateral ventricle yields reproducible intracranial hypotension of up to -15 torr for several hours to -80 torr of about 10 minutes. The magnitude of this hypotension is significantly greater than can be attained by cisterna magna drainage. This new model allows multiple cerebral parameters to be studied during intracranial hypotension. In 11 cats with stable blood pressure and intracranial hypotension of at least -15 torr, regional blood flow utilizing the hydrogen clearance method in the cerebral cortex and subcortical nuclei was unchanged relative to the baseline. These results imply that: 1) cerebral vascular autoregulation is maintained during significantly increased perfusion pressure due to negative intracranial pressure, 2) the symptomatology of clinical intracranial hypotension is not due to decreased cerebral perfusion.

[Individual dosimetry and biologic monitoring of workers exposed to low concentrations of aniline]. / Dosimetria individuale e monitoraggio biologico in esposti a basse concentrazioni di anilina.

Low aniline vapours concentration exposure has been studied through either active or passive individual dosimeter, in a group of workmen employed in the production of an antioxidant for the rubber industry. We collected 28 samples, confirming the clear correlation existing between the two methods which was already demonstrated in a previous work. We newly suggest the usefulness of the individual passive dosimeter instead of the traditional vacuum pump system. Meanwhile we have determined bound and free aniline and total aromatic amines, with and without an extractive method on column, on urinary samples collected before and after the workshift. The values so obtained have been compared with the results of the active individual dosimetry. We could demonstrated a statistical significative correlation only between urinary aniline determination and the level of exposure, so confirming the value of this parameter as biological indicator of occupational exposure.