Severe root resorption of the upper central incisors as a consequence of playing the flute.

This study presents a case of severe root resorption of the maxillary central incisors in an 18-year-old woman who was referred for orthodontic treatment of irregular dental arches. A detailed history revealed that she used to play the block flute on an everyday basis during childhood. Against all warnings, she continued to firmly press her teeth into the mouthpiece of the instrument. Impressions of the upper central incisors were clearly visible on the instrument. Although it is well known that excessive occlusal forces can result in root resorption, to the authors' knowledge, this case involves one of the first reported occurrences of extensive root resorption that was most likely caused by playing a wind instrument during childhood.

[Neurophysiological background of pain in the orofacial area: review of the literature]. / Az orofaciális terület fájdalmainak neurofiziológiai háttere. Osszefoglaló referátum.

The article presents an overview on the peripheral and central neural mechanisms underlying pain in the orofacial area. First a definition of pain and a description of general aspects of orofacial pain are presented. Characteristics of acute and chronic pain are also described. The study highlights the sense organs, the molecular mechanisms and categories of primary afferents involved in peripheral events of orofacial pain. After describing the brain-stem nuclei participating in trigeminal pain and their functional role, primary afferents involved in nociceptive sensation from the tooth pulp, explanations of dentinal sensitivity and differences between the brain-stem endings of primary afferents among different species are discussed in details. The role of higher brain centres, with a special emphasis on the thalamus and somatosensory cortex in the development of orofacial pain sensation is considered. The last section provides a review about how the activities of nociceptive neurons are controlled by higher brain centres and neurochemicals involved in pain transmission.

[Model investigation of push-out test used for quantitative evaluation of dental implant osseointegration]. / Fogászati implantátumok osszeointegrációjának kvantitatív minósítésére szolgáló kinyomási próba modellvizsgálata.

A frequently used method for quantitative evaluation of implant-bone interface strength is the push-out test. The objective of the authors' study was to determine the effect of implants' geometric characteristics on the results of push-out method. The degree of osseointegration is determined by a complicated interaction of mechanical, biological and chemical factors. As this study focused on the effects of geometrical characteristics of dental implants, the authors tried to reduce the influence of biological and chemical factors as much as possible. For this reason a model of push-out test was set up. Cylindrical metal rods were imbedded in acrylic resin and were pushed out, meanwhile the force needed to disrupt the connection between the surface of the metal rods and the resin was measured and push-out strengths were calculated. Metal rods with three different lengths (7, 9, and 13 mm) and three different diameters (3.4, 4, 4.5 mm) were investigated. No correlation was found between implant length and maximum push-out strength. The mean push-out strengths were 17.32 MPa, 15.99 MPa and 15.56 MPa in groups, with 3.4, 4 and 4.5 mm diameter, thus the push-out strength decreases with increasing metal rod diameter. This may be attributed to the different distance between the outer circumference of the metal rods and the hole of the supporting table. Supporting this theory metal rods with identical diameter were examined, while the diameter of the hole on the supporting table was changed. The results demonstrated that larger holes on the supporting table resulted in higher push-out strengths. This indicates that comparisons of this variable should only be performed with standardized clearance of the hole on the supporting table. Push-out strengths of groups of cylindrical and conical implants with 9 degrees convergence were also investigated. The mean values were 16.57 MPa and 16.43 MPa, respectively. There was no statistically significant difference between the two groups. This means that results of experiments with all the above mentioned implant types are comparable, at least to that degree of conicity. As masticatory forces act usually on a surface, which is not perpendicular to the implant axis, we compared forces and push-out strengths that acted on surfaces with 10 degrees and 15 degrees inclination. The calculated average push-out strengths were 24.89 MPa and 22.56 MPa, respectively. More than twice as high push-out strengths were measured when threaded metal rods were compared to unthreaded ones (30.15 MPa, 14.89 MPa, respectively). Examining the effect of pitch of threads we compared the mean push-out strengths in three groups of threaded metal rods with pitch of threads 0.7, 1.0 and 1.25. The results were 28.86 MPa, 30.48 MPa, 31.12 MPa, respectively. The differences can be explained with the alteration in the dimension of the interface covered by the acrylic resin. Thus the effect of diameter, inclined opposing surface and threads must not be ignored if one compares the osseointegration capacity of different implants.