Predictability of a New Orthodontic Extrusion Technique for Implant Site Development: A Retrospective Consecutive Case-Series Study.

In clinical daily practice, there are situations in which implant sites have vertical and/or horizontal bone defects and often we must improve their morphology and dimensions before fixture insertion. It is crucial to carefully evaluate the surgical site as regards the characteristics of both hard and soft tissues. The orthodontic extrusion technique can be used for nonsurgical augmentation of the implant site as an alternative to traditional regenerative/reparative surgical therapies. The orthodontic extrusion is based on a biological mechanism that uses the portion of periodontal ligament, still present on the root before the tooth extraction, for the increase of hard and soft tissues. In the literature, there is no evidence of common guidelines for this technique but only tips based on personal experience and/or previous studies. The aim of this study was to investigate and to validate the reliability of a new orthodontic extrusion technique (MF Extrusion Technique, by Dr. Mauro Fadda) by means of a retrospective consecutive case-series study. After we have done a review of the literature, we evaluated the X-rays of twelve consecutively treated patients before the orthodontic extrusion (T0) and after the stabilization period (T1), in order to quantify, by two different measurements, area and linear, the bone gain obtained by the application of the new technique. All the patients examined showed a significant increase in bone areas with an average value of 31.575 mm2. The linear bone gain had an average value of 4.63 mm. Data collected were statistically analysed by the Wilcoxon signed-rank test. The results obtained both from area and linear measurements at T0 and at T1 times showed that there was a statistically significant bone gain with p < 0.01.

Cytotoxicity in vitro analysis of ceramic materials for ''metal free'' prosthetic substructures.

AIM: The aim of this study was to investigate the in vitro cytotoxicity of 5 ceramic materials for metal-free fixed prosthodontics: In-Ceram, Cergo, IPS Empress II, Cercon ZrO2, Finesse All Ceram compared each other and to commercially pure Titanium (CpTi). METHODS: The materials, prepared directly from manufacturers as 10 mm diameter and 3 mm thickness disks, have been tested following the ISO 10993-l guidelines, performing the in vitro cytotoxicity test with the use of mouse's cells, fibroblasts L-929, isolated by muscular tissue and cultured in an appropriate medium. The MTT test has been used to evaluate the cell viability through the succinate dehydrogenase enzyme activity. The originality of this investigation is that all the materials examined have been tested under the same conditions: the cytotoxicity test has been performed on these materials at the same time, in the same period, under the same conditions of temperature and humidity and by the same operator. RESULTS: Not all tested materials were free from cytotoxicity. Cercon, within the limits of this in vitro study, showed the lower cytotoxicity. CONCLUSIONS: This in vitro study suggested that ceramic materials for metal free prosthetic substructures are in competition with the CpTi which is very used in implant prosthodontics.

[An in vitro study of the tensile strength of a new titanium root post with respect to the type of luting cement used]. / Studio in vitro della resistenza alla trazione di nuovo perno endocanalare in titanio in relazione al tipo di cemento utilizzato.

BACKGROUND: Assessing the retentive capabilities of a new titanium root post (Optipost, Komet-Gebr. Brasseler, GmbH and Co. KG Lemgo, Germany) with a decreasing diameter shape (turret like) and how these can be improved by the choice of fixing cement. METHODS: The tensile strength was assessed in relation to the type of cement used. The following cements were tested: Compolute composite cement (Espe), C/B Crown & Bridge Luting Composite (Bisco), Diamond Link cement (DRM) with Harvard cement as a control. The cementing procedures laid down by the manufacturers were followed in the case of each cement. The results of the traction tests were analysed and compared statistically and a SEM evaluation of the root/cement and cement/post interface was carried out. RESULTS: The results showed that the highest absolute mean value (best performance) was Diamond Link cement (46.48+/-14.31 kg) which also came out best in the statistical analysis (Scheffe Test p=0.007). Analysis of the samples at the SEM confirmed the results of the traction tests. CONCLUSIONS: The characteristic <> form of the Optipost root post and the sanding of the surface would appear to be important factors which, together with the adhesive cementing technique, lead to a high decementing resistance.

Habitual mastication in dysfunction: a computer-based analysis.

To study the different parameters of habitual mastication in stomatognathic dysfunction, mandibular movements and electromyographic activity of the elevator muscles were recorded during three chewing sequences in 86 dysfunctional subjects. The Dysfunction Index system was used to treat two subgroups, patients with severe temporomandibular joint impairment and patients with severe muscle dysfunction. Data on the different parameters of mastication from the single patients, the whole group, and the two subgroups were statistically assessed and compared with those from 12 normal individuals. The following conclusions were drawn. (1) In dysfunctional patients the normal symmetrical and balanced distribution of the chewing cycles is lost and movements are more restricted. (2) The electromyographic data show marked alterations with a tendency to reduce or suppress the isometric phase of contraction during closing in the temporomandibular joint patients. This can be viewed as a defensive mechanism of the impaired system. (3) The data at hand are helpful in explaining some of the mechanisms that lead to muscle pain in dysfunctional patients.

[Analysis of mastication in normal and dysfunctional subjects]. / Analisi della masticazione in soggetti normali e disfunzionali.

A computer based system to asses mandibular movements and EMG masseter and temporal muscle activity during habitual mastication was applied to 12 healthy subjects and to 86 dysfunctional subjects, the chewing performance was tested with a standardized bolus of crispy bread. A Siemens Sirognathograph instrument was used to record mandibular movements, while EMG signals were recorded with surface Ag/AgCl electrodes. The Dysfunction Index System was used to build two subgroups of patients with severe TMJ impairment (n = 21) and severe muscle dysfunction (n = 15) respectively. Data on the different parameters of mastication were obtained for the single patients, the whole group and the two subgroups were statistically compared together with those obtained from normal individuals.