Stability of the hard and soft tissue profile after mandibular advancement in sagittal split osteotomies: a longitudinal and long-term follow-up study

The aim of the study was to conduct a long-term follow-up investigation of the stability of hard and soft tissues after bilateral sagittal split osteotomy (BSSO) with rigid internal (RIF) fixation to advance the mandible. Sixteen consecutive patients (12 females and 4 males, mean age 21.4 years) were available for re-examination 12.7 years (T5) after surgery. The preceding follow-ups were before (T1), and 5 days (T2), 7.3 months (T3), and 13.9 months (T4) after surgery. Lateral cephalograms were traced by hand, digitized, and evaluated with the Dentofacial Planner program. The x-axis for the system of co-ordinates ran through sella (point zero) and the line NSL -7 degrees. Thus, the program determined the x- and y-values of each variable and the usual angles and distances. Statistical analysis was carried out using Wilcoxon's matched-pair signed-ranks test with Bonferroni adjustments. The relationships between the examined variables were analysed by Spearman rank correlation coefficients. The backward relapse at point B (T5) was 2.42 mm, or 50 per cent, and at pogonion 3.21 mm, or 60 per cent of the initial advancement. The mean net effect at T5 on the labial fold (soft tissue point B) was 94 per cent of the advancement at point B. For the soft tissue chin (soft tissue pogonion), it was 119 per cent of the advancement at pogonion. The net effect on the lower lip (labrale inferior) was 55 per cent of the advancement at incision inferior. The amount of the surgical advancement of the mandible was correlated with the long-term relapse in point B. Among possible reasons for this relapse are the initial soft tissue profile, the initial growth direction, and the remodelling processes of the hard tissue.

Stability of hard tissue profile after mandibular setback in sagittal split osteotomies: a longitudinal and long-term follow-up study

The aim of the study was to conduct a long-term follow-up on the stability of the hard tissues after bilateral sagittal split osteotomy (BSSO) with rigid internal fixation (RIF)to set back the mandible and to compare it with that of mandibular advancement performed by the same team of surgeons and with the same examination protocol. Seventeen consecutive patients (6 females and 11 males) could be re-examined 12.7 years (T5) after surgery. The previous examinations were before surgery (T1), 5 days (T2), and 6.6 (T3) and 14.4 (T4) months after surgery. Lateral cephalograms were traced by hand, digitized, and evaluated with the Dentofacial Planner software program. The x-axis for the system of co-ordinates ran through sella (point zero) and the line nasion-sella-line minus 7 degrees. The program determined the x- and y-values of each variable and the usual angles and distances. The effects of treatment were determined with Wilcoxon matched pairs, signed ranks test, with Bonferroni adjustment, and the relationship between variables with Spearman rank correlation coefficient. Relapse at point B was 0.94 mm or 15 per cent and at pogonion 1.46 mm or 21 per cent of the initial setback at T5. Relapse was mainly short-term (T4-T2), 13 per cent for point B and 17 per cent for pogonion. Gender correlated significantly with relapse (T5-T2) at point B (P = 0.002) and pogonion (P = 0.021), i.e. females in contrast to males showed further distalization of the mandible instead of relapse. No correlations were seen for age or the amount of surgical setback. The long-term results in mandibular setback patients were more stable when compared with the mandibular advancement patients examined previously. The initial soft tissue profile, the initial growth direction, and the remodelling processes of the hard tissues must be considered as reasons for long-term relapse. Growth direction positively influenced the long-term results in females: further distalization of the mandible occurred.

[Casein phosphopeptide--amorphous calcium phosphate (CPP-ACP) and its effect on dental hard tissues]

Dental products with casein phosphopeptide--amorphous calcium phosphate-nanocomplexes (CPP-ACP) are used in several tooth products (toothpastes, chewing gums, mouthrinses) and are as well used in dental filling material. CPP-ACP containing products are supposed to enhance remineralisation of dental hard tissues und thus might play a major role in prevention and therapy of initial caries or erosively dissolved enamel. Furthermore, also in hypersensitive teeth and even cases of hyposalivation, CPP-ACP containig products are supposed to improve the clinical condition. This article aims at three goals: point out the evolvement of CPP-ACP out of milk casein; description of possible biochemical effects of CPP-ACP on dental hard tissues; critical review of the current literature.

The pollen tube: a soft shell with a hard core

Plant cell expansion is controlled by a fine-tuned balance between intracellular turgor pressure, cell wall loosening and cell wall biosynthesis. To understand these processes, it is important to gain in-depth knowledge of cell wall mechanics. Pollen tubes are tip-growing cells that provide an ideal system to study mechanical properties at the single cell level. With the available approaches it was not easy to measure important mechanical parameters of pollen tubes, such as the elasticity of the cell wall. We used a cellular force microscope (CFM) to measure the apparent stiffness of lily pollen tubes. In combination with a mechanical model based on the finite element method (FEM), this allowed us to calculate turgor pressure and cell wall elasticity, which we found to be around 0.3 MPa and 20–90 MPa, respectively. Furthermore, and in contrast to previous reports, we showed that the difference in stiffness between the pollen tube tip and the shank can be explained solely by the geometry of the pollen tube. CFM, in combination with an FEM-based model, provides a powerful method to evaluate important mechanical parameters of single, growing cells. Our findings indicate that the cell wall of growing pollen tubes has mechanical properties similar to rubber. This suggests that a fully turgid pollen tube is a relatively stiff, yet flexible cell that can react very quickly to obstacles or attractants by adjusting the direction of growth on its way through the female transmitting tissue.

Soft and hard tissue histologic dimensions around dental implants in the canine restored with smaller-diameter abutments: a paradigm shift in peri-implant biology

PURPOSE To evaluate the biologic width dimensions around implants with nonmatching implant-abutment diameters. MATERIALS AND METHODS Five canines had their mandibular premolars and first molars removed bilaterally and replaced with 12 implants that had nonmatching implant-abutment diameters. On one side, six implants were placed in a submerged surgical approach, and the other side utilized a nonsubmerged approach. Two of the implants on each side were placed either 1 mm above, even with, or 1 mm below the alveolar crest. Two months later, gold crowns were attached, and the dogs were sacrificed 6 months postloading. Block sections were processed for histologic and histomorphometric analyses. RESULTS The bone level, connective tissue length, epithelial dimension, and biologic width were not significantly different when the implants were initially placed in a submerged or nonsubmerged surgical approach. The bone level was significantly different around implants placed 1 mm above the crest compared to implants placed even with or 1 mm below the alveolar crest. The connective tissue dimension was not different for any implant level placement. The epithelial dimension and biologic width were significantly greater for implants placed 1 mm below the alveolar crest compared to implants placed even with or 1 mm above the alveolar crest. For five of six implant placements, connective tissue covered the implant/abutment interface. CONCLUSIONS This study reveals a fundamental change in the biologic response to implants with nonmatching implant-abutment diameters. Unlike implants with matching implant-abutment diameters, the connective tissue extended coronally past the interface (microgap). This morphologic tissue alteration represents a significant change in the biologic reaction to implant-abutment interfaces and suggests that marginal inflammation is eliminated or greatly reduced in these implant designs.

A scrutiny of hard pion chiral perturbation theory

In the recently proposed framework of hard pion chiral perturbation theory, the leading chiral logarithms are predicted to factorize with respect to the energy dependence in the chiral limit. We have scrutinized this assumption in the case of vector and scalar pion form factors FV;S(s) by means of standard chiral perturbation theory and dispersion relations. We show that this factorization property is valid for the elastic contribution to the dispersion integrals for FV;S(s) but it is violated starting at three loops when the inelastic four-pion contributions arise.

10001 manuscripts in practice: Perl, XML, medieval chronicles, and why Unicode rocks‎

I work in the field of Armenian historiography. This means I get to play with medieval manuscripts. The things I'm doing with the manuscripts are theoretically interesting, but pretty boring in practice, so I'm using Perl to program away the most boring bits. I will talk about the problems of text criticism in general, what sorts of things can and can't be done by the computer, my initial aversion to XML, how I was shown (some of) the error of my ways, and how I'm combining a bunch of isolated pieces of technology that were mostly already in use to achieve fame and fortune in the world of Armenian studies.

Hard thermal loop benchmark for the extraction of the nonperturbative QQ[over ¯] potential

The extraction of the finite temperature heavy quark potential from lattice QCD relies on a spectral analysis of the Wilson loop. General arguments tell us that the lowest lying spectral peak encodes, through its position and shape, the real and imaginary parts of this complex potential. Here we benchmark this extraction strategy using leading order hard-thermal loop (HTL) calculations. In other words, we analytically calculate the Wilson loop and determine the corresponding spectrum. By fitting its lowest lying peak we obtain the real and imaginary parts and confirm that the knowledge of the lowest peak alone is sufficient for obtaining the potential. Access to the full spectrum allows an investigation of spectral features that do not contribute to the potential but can pose a challenge to numerical attempts of an analytic continuation from imaginary time data. Differences in these contributions between the Wilson loop and gauge fixed Wilson line correlators are discussed. To better understand the difficulties in a numerical extraction we deploy the maximum entropy method with extended search space to HTL correlators in Euclidean time and observe how well the known spectral function and values for the real and imaginary parts are reproduced. Possible venues for improvement of the extraction strategy are discussed.