The impact of intraoperative frozen section analysis on final resection margin status,recurrence, and patient outcome with oral squamous cell carcinoma

Clinical Oral Investigations - The objective of this study was to evaluate the diagnostic value of intraoperative frozen section analysis (IFSA) of tumor bed margins in patients with oral squamous...     

Peri-implant soft tissue integration of immediately loaded implants in the posterior macaque mandible: a histomorphometric study

BACKGROUND: Today, one critical goal in implant placement is the achievement of optimal soft tissue integration. Reports thus far have demonstrated successful soft tissue preservation in delayed loaded implants placed in anterior jaws. The aim of this study was to histomorphometrically examine the soft tissues around immediately loaded implants placed in the macaque posterior mandible. METHODS: Splinted crowns on screw-shaped titanium implants (8 mm length, 3.5 mm diameter) were utilized. Three implants each were placed in the premolar-molar edentulous mandibular segments of 6 adult monkeys (Macaca fascicularis); one side served as the control (delayed loading) and the other as the test sites (immediate loading). The animals were sacrificed after 3 months of loading. Histomorphometry of 6 soft tissue indices including the sulcus depth (SD), junctional epithelium (JE), connective tissue contact (CTC), biologic width (BW = SD + JE + CTC), DIM (distance between the implant top and coronal gingiva), and DIB (distance between the implant top and first implant-to-bone contact) was performed on non-decalcified sections. RESULTS: No significant differences in the mean soft tissue scores (mm) between the test (SD = 0.68 +/- 0.63; JE = 1.71 +/- 1.04; CTC = 1.51 +/- 1.14; DIM = 2.27 +/- 1.18; DIB = 1.32 +/- 1.21; BW = 3.9) and control (SD = 0.88 + 0.57; JE = 1.66 + 0.77; CTC = 1.24 +/- 0.92; DIM = 2.38 +/- 0.81; DIB = 1.19 +/- 0.91; BW = 3.78) groups were observed (P > 0.01). CONCLUSION: These findings suggest that the dimensions of the peri-implant soft tissues were within the biologic range and were not influenced by immediate functional loading or posterior location of the implants in the macaque mandible.     

Ankylos implant system: concept and clinical application

PROBLEM: The Ankylos system was developed in 1985 and has been in clinical use since 1987. Some of its significant design features include (1) a progressive thread structure of the endosseous implant body for targeted load distribution to the apically positioned spongy bone; and (2) the gap-free subgingival tapered connection to the abutments. PURPOSE: The purpose of this report is to demonstrate that the Ankylos Implant System meets both the patients' and the dentists' standards of success and is suitable for use as single tooth replacements, bridge abutments, and retention elements for all regions and prosthetic indications. METHOD: The data from 5439 implants were evaluated between October 1991 and October 2002. The implants were considered successful if the following criteria were met: (1) clinical stability and function; (2) no inflammation of the peri-implant hard and soft tissue; (3) no progressive loss of the peri-implant bone; (4) no progressive loss of the peri-implant mucosa; and (5) satisfaction of the patient. All implants placed during this period were included in the evaluation as a prospective study. The average loading period was 56.8 months. Postoperative follow-ups were made once a year by a standardized protocol. The results were classified by prosthetic application in Table 1. A total of 943 implants were placed as single tooth restoration and were followed for the duration of the study. RESULTS: The success rate for this type of restoration was 98.7%. For free-end implant restorations, there were 1679 implants placed with a 97.9% success rate. When the edentulous area involved a large gap, a total of 805 implants were placed with a 97.3% success rate. For cases involving reduced dentition, 606 implants were used with a 95.8% success rate. Another significant finding was that the success rates classified by maxilla and mandible showed no differences.     

Ring-testing and Field-validation of a Terrestrial Model Ecosystem(TME) – An Instrument for Testing Potentially Harmful Substances: Effects of Carbendazim on Organic Matter Breakdown and Soil Fauna Feeding Activity

Organic matter (OM) decomposition and soil fauna feeding activity were integrated as functional endpoints into ecotoxicological tests with intact-soil-core Terrestrial Model Ecosystems (TMEs). Cellulose filter paper served as standardized OM and was either inserted into the top soil or placed on the soil surface for a period of up to 16 weeks. Faunal feeding activity was assessed by the bait-lamina method. The fungicide carbendazim, applied at six dosages ranging from 0.36 kg/ha to 87.5 kg a.i./ha, served as a model chemical. To validate the results from the TME test, a field study was run in parallel. In TMEs the cellulose paper inserted into the soil was decomposed faster than under field conditions. The carbendazim-induced effects on OM decomposition in TMEs and in the field were comparable and followed a clear dose-response relationship. The calculated EC50 values after 8 weeks of incubation were 9.5, 7.1 and 2.1 kg carbendazim/ha for grassland TMEs, grassland field and arable TMEs, respectively. The feeding activity of the soil fauna showed a large variability. The EC50 values for the effect of carbendazim on bait-lamina consumption ranged between 2.0 and 56 kg a.i./ha. Effects on decomposition were correlated with effects on enchytraeids and earthworms but not with effects on bait-lamina consumption.     

Immobilizing and lethal effects of spider venoms on the cockroach and the common mealbeetle

Immobilizing and lethal effects of the venoms obtained from six spider species (Brachypelma albopilosum, Atrax robustus, Cupiennius salei, Selenops mexicanus, Tegenaria atrica, Argiope bruennichi) were tested on Blatta orientalis (cockroach) and Tenebrio molitor (common mealbeetle). The immobilizing effects were quantified by measuring insect locomotor activity in circle arenas observed over 72 hr after venom injection. Both insect species showed cramps, quivering and jerking of the limbs as well as flaccid paralysis after venom injection. Through relative toxicity of the venoms tested is the same in T. molitor and B. orientalis, T. molitor is absolutely less sensitive to spider venoms. The effects on locomotor activity show time characteristics specific for each venom. A dependence of the venom paralyzing effects on insect locomotor activity, low intensity of the initial excitatory phase of the venom effects and partial recovery of the insects was found with A. bruennichi and T. atrica venom. The maximal venom yields of A. bruennichi and S. mexicanus are not lethal to B. orientalis, indicating that the mere immobilizing effects of spider venoms are far more crucial to prey capture than their lethal effects. The contribution of a variety of differently acting neurotoxic components in spider venoms to the observed venom effects on insects and the significance of the venoms in spider nutrition, hunting behaviour and ecology are discussed.     

The influence of hunger and breeding temperature on the venom production of the spider Cupiennius salei (Araneae, Ctenidae).

The venom production of the free hunting neotropic spider Cupiennius salei was tested under different breeding conditions. Three groups kept at different temperatures (17, 21 and 25 degrees C) showed that venom production remained stable within this temperature range, only at a temperature of 15 degrees C the spiders stopped feeding and venom synthesis. Hunger periods do not have a direct effect on the released venom quantity. Two groups of spiders--the first group after a four and the second after an eight weeks hunger period--were compared and no difference in venom production was found. Such long fasting periods are a natural situation for spiders. In this case Cupiennius salei reduces its body weight but not venom supply. This means that body weight is a parameter only of short-term fitness which changes with the actual living conditions (temperature, feeding intervals) of each individual. Long-term fitness is best described by the prosoma length, which was formed during the juvenile growth of each spider and is rather invariable in adulthood. It was shown that the quantity of released venom is better correlated with the length of the prosoma than with the weight of the animal. This means that venom production is mostly an indicator of long-term fitness.