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Item does not contain fulltext The dentition of 116 patients with a non-syndromic form of oligodontia was characterized. For this purpose use was made of the so-called Tooth Agenesis Code (TAC), with which the various patterns of missing teeth can be indicated with a unique number. Oligodontia can present itself in very diverse ways. Only 3 patterns were seen (2 times) among these 116 patients. Considered per quadrant, in the upper jaw, on the one hand, agenesis of both premolars and the lateral incisor was most common and, on the other, the absence of all teeth except the central incisor and the first molar. In the lower jaw, agenesis of the second or of both premolars was most common. Evaluating treatments and formulating standards of restoration in the treatment of patients with severe oligodontia are methodological challenges. Homogeneous, comparable sub-groups of patients of any size are difficult to construct due to the low prevalence of severe oligodontia and the diversity of patterns of agenesis when the whole mouth is taken into consideration.

Item does not contain fulltext In clinical practice, the prognosis seems, with some reservations, to be comparable for tooth-implant and implant-implant supported bridges in the middle-long term.This conclusion seems particularly valid for tooth-implant bridges in free-end situations, where a single implant is connected with a tooth. Prerequisites are a healthy tooth abutment, a pontic length not exceeding the width of a bicuspid, a rigid connection between implant and tooth and the use of strong cement.

Purpose: Radiographic parameters of mandibular trabecular bone structure between 67 subjects having hypodontia and those without were studied on digital panoramic radiographs.Materials and Methods: Three regions of interest (ROI) were defined: the ascending ramus, apical of the mandibular molar and mesial of the first mandibular molar. The effects of the presence of hypodontia and the ROI on the mandibular trabecular bone structure were tested for statistical significance by means of multivariate analysis.Results: Radiographic parameters of trabecular bone architecture were found to differ between various regions of the mandible (p = 0.000), but not between the group of hypodontia subjects and their controls (p = 0.23). There was no interaction effect between the ROIs and the two groups (p = 0.79). For people having hypodontia, some directional parameters of trabecular bone have a reverse correlation with the number of missing teeth. The fractal dimension and the number and perimeter of white segments in the binarized image correlate positively with the number of congenitally missing teeth.Conclusions: A limited number of parameters of radiographic mandibular trabecular bone structure correlate with the number of missing teeth. However, a markable difference in radiographic parameters of mandibular trabecular bone structure between hypodontia and non-hypodontia subjects could not be demonstrated.

Aim: To compare the early bacterial colonization and soft tissue health of mucosa adjacent to zirconia (ZrO2) and titanium (Ti) abutment surfaces in vivo.Materials and methods: Twenty edentulous subjects received two endosseous mandibular implants. The implants were fitted with either a ZrO2 or a Ti abutment (non-submerged implant placement, within-subject comparison, left-right randomization). Sulcular bacterial sampling and the assessment of probing pocket depth, recession and bleeding on probing were performed at 2 weeks and 3 months post-surgery. Wilcoxon matched-pairs, sign-rank tests were applied to test differences in the counts of seven marker bacteria and the clinical parameters that were associated with the ZrO2 and Ti abutments, at the two observation time points.Results: ZrO2 and Ti abutments harboured similar counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Peptostreptococcus micros, Fusobacterium nucleatum and Treponema denticola at 2 weeks and 3 months. Healthy clinical conditions were seen around both ZrO2 and Ti abutments at all times, without significant differences in most clinical parameters of peri-implant soft tissue health. Mean probing depths around Ti abutments were slightly deeper than around ZrO2 abutments after 3 months (2.2 SD 0.8 mm vs. 1.7 SD 0.7 mm, P=0.03).Conclusions: No difference in health of the soft tissues adjacent to ZrO2 and Ti abutment surfaces or in early bacterial colonization could be demonstrated, although somewhat shallower probing depths were observed around ZrO2 abutments after 3 month.

Purpose: A retrospective study on the performance of endosseous implants in a population of patients with severe epilepsy and additional motor and/or intellectual impairments was performed. Materials and Methods: All residents of an inpatient center for persons affected by severe, refractory epilepsy and multiple disabilities who received endosseous implants between 1991 and April 2007 were included in the study. Implant survival was analyzed using the Kaplan-Meier method. A subset of patients who were treated between 1991 and 2004 was invited to participate in a clinical and radio­graphic evaluation in 2004 and 2005. Results: A total of 61 patients were treated between 1991 and April 2007 (n = 134 implants). Three of these implants in three different patients failed during the observation period, demonstrating an estimated probability of functional implant survival of 97.6% (SE 1.4%) after 16 years. In patients who were seen during the clinical evaluation in 2004 (n = 76 implants), only mild inflammation of the peri-implant mucosa was generally observed (Gingival-Bleeding Index = 1), despite the fact that the level of oral hygiene was considered inadequate around 55 of 76 implants (72%). Obvious signs of drug-induced gingival hyperplasia in relation to the implants were not observed. Probing depths averaged approximately 2 mm. Stable marginal bone levels were observed on the radiographs. Conclusions: Dental implant treatment in a population of patients with severe epilepsy and additional disabilities seems to be a viable treatment option. Implant loss is rare. Although adequate plaque control was not feasible in all patients, marginal bone levels remained stable.

The chromophore of photoactive yellow protein (PYP) (i.e., 4- hydroxycinnamic acid) has been replaced by an analogue with a triple bond, rather than a double bond (by using 4-hydroxyphenylpropiolic acid in the reconstitution, yielding hybrid I) and by a 'locked' chromophore (through reconstitution with 7-hydroxycoumarin-3-carboxylic acid, in which a covalent bridge is present across the vinyl bond, resulting in hybrid II). These hybrids absorb maximally at 464 and 443 nm, respectively, which indicates that in both hybrids the deprotonated chromophore does fit into the chromophore-binding pocket. Because the triple bond cannot undergo cis/trans (or E/Z) photoisomerization and because of the presence of the lock across the vinyl double bond in hybrid II, it was predicted that these two hybrids would not be able to photocycle. Surprisingly, both are able. We have demonstrated this ability by making use of transient absorption, low- temperature absorption, and Fourier-transform infrared (FTIR) spectroscopy. Both hybrids, upon photoexcitation, display authentic photocycle signals in terms of a red-shifted intermediate; hybrid I, in addition, goes through a blue-shifted-like intermediate state, with very slow kinetics. We interpret these results as further evidence that rotation of the carbonyl group of the thioester-linked chromophore of PYP, proposed in a previous FTIR study and visualized in recent time-resolved x-ray diffraction experiments, is of critical importance for photoactivation of PYP.

Six new donor-bridge-acceptor compounds have been synthesized which contain a long n-tetradecyl chain attached to the donor or acceptor moiety, or to both of them. Systems 1, 2, and 3 are analogs of the fluorescent probe molecule Fluoroprobe (4). They contain a rigidly extended 4-methylenepiperidine bridge and show relatively strong charge transfer fluorescence in solvents of low and medium polarity. Systems 1a, 2a, and 3a contain a semiflexible 4-methylpiperidine bridge, obtained after hydrogenation of the exocyclic double bond of 1, 2 and 3, respectively. These systems undergo a conformational change following photoinduced charge separation (harpooning) in nonpolar solvents and probably also in solvents of medium polarity. Both the steady state fluorescence spectra and the fluorescence decay times of the extended charge transfer (ECT) species show that the photoinduced folding process is effectively slowed down by the introduction of the long alkyl tails. This is most pronounced for 1a which has an n-tetradecyl group attached to both donor and acceptor. In solution a small difference in the rate of folding is observed between 2a and 3a, which have a single n-tetradecyl chain attached to the acceptor only and to the donor only, respectively.