Hermann Stich

Performance of laser fluorescence devices, visual and radiographic examination for the detection of occlusal caries in primary molars

The aim of this in vitro study was to compare the performance of two laser fluorescence devices (LF, LFpen), conventional visual criteria (VE), ICDAS and radiographic examination on occlusal surfaces of primary teeth. Thirty-seven primary human molars were selected from a pool of extracted teeth, which were stored frozen at −20°C until use. Teeth were assessed twice by two experienced examiners using laser fluorescence devices (LF and LFpen), conventional visual criteria, ICDAS and bitewing radiographs, with a 2-week interval between measurements. After measurement, the teeth were histologically prepared and assessed for caries extension. The highest sensitivity was observed for ICDAS at D1 and D3 thresholds, with no statistically significant difference when compared to the LF devices, except at the D3 threshold. Bitewing radiographs presented the lowest values of sensitivity. Specificity at D1 was higher for LFpen (0.90) and for VE at D3 (0.94). When VE was combined with LFpen the post-test probabilities were the highest (94.0% and 89.2% at D1 and D3 thresholds, respectively). High values were observed for the combination of ICDAS and LFpen (92.0% and 80.0%, respectively). LF and LFpen showed the highest values of ICC for interexaminer reproducibility. However, regarding ICDAS, BW and VE, intraexaminer reproducibility was not the same for the two examiners. After primary visual inspection using ICDAS or not, the use of LFpen may aid in the detection of occlusal caries in primary teeth. Bitewing radiographs may be indicated only for approximal caries detection.

Degradation of hydroxyapatite coating on a well-functioning femoral component.

We carried out a histological study of a proximally hydroxyapatite (HA)-coated femoral component, retrieved after 9.5 years of good function. The HA coating had completely degraded. Bone was in direct contact with the titanium surface in all the areas which had been coated, with no interposing fibrous tissue. There were no signs of particles, third-body wear, adverse tissue reactions or osteolysis. Bone remodelling was evident by the presence of resorption lacunae; tetracycline labelling showed bone laid down six years after implantation. The loss of the HA-coating had no negative effect on the osseo-integration of the stem. We conclude that the HA coating contributes to the fixation of the implant and that its degradation does not adversely affect the long-term fixation.

Observations of the Periodontal Ligament and Cementum in Cats with Dental Resorptive Lesions

The etiology of feline dental resorptive lesions is unknown, but some evidence suggests that interactions between components of the periodontium may be initiating factors in the development of these lesions. In the present study, 22 clinically normal teeth were harvested from 7 cats. The teeth and periodontium were radiographed and examined histologically. In addition, 14 of the 22 teeth were examined histometrically. Two teeth were histologically normal with an open apical foramen and two were normal with a closed apical foramen. Histological evidence of periodontal ligament degeneration without cementum resorption was observed in 8 teeth, and varying degrees of cementum resorption were observed in 10 teeth. Mandibular molar and premolar teeth had distal drift, and mandibular canine teeth had mesial drift. Alterations in the periodontal ligament may represent a preclinical stage of dental resorption.

Oral examination and radiographic evaluation of the dentition in wild cats from Namibia.

Feline tooth resorption has been widely reported in domestic cats and sporadically described in other felidae. The goal of the present study was to determine the prevalence of tooth resorption and to report other dental problems in a population of wild felidae. Observations of dental disorders and anomalies were made in skulls from 73 wild felidae (cheetahs, leopards, caracals, African wildcats, and lions) originating from Namibia. In addition, radiographs were taken in 43 cases to determine signs of bone and root pathology. Radiographs showed varying stages of tooth resorption in 16.0 % of the specimens. Other dental anomalies found included fused teeth, supernumerary roots, or missing teeth. The prevalence of dental resorption in wild felidae was lower than reported in the domestic cat.

Feline Dental Resorptive Lesions in the 13th to 14th Centuries

The Schild excavation (1971–1975) unearthed 1871 feline bones from at least 181 cats firm rite town market in medieval Schleswig-Gottorf. Seven of the 189 mandibles and one of the 126 skulls were investigated using a combination of macroscopic, radiographic, and histologic examinations as well as Knoop hardness measurements. The preliminary results of examinations of three mandibles and one skull are presented and reveal that feline dental resorptive lesions were present in cats that lived in a settlement period dating from the 13th and 14th centuries in former Schleswig, Germany.

Bilateral malformation of maxillary third molars

A case of bilateral compound odontomas in the region of the third molars in the maxilla is reported. The differential diagnosis for this case is discussed.

Feline Caries in Two Cats from a 13th Century Archeological Excavation

Mandibles of two cats containing carious lesions were discovered among the previously published findings of feline dental resorptive lesions from materials examined at an archaeological museum. These lesions were too small to be noted on radiographs, and consisted of two inconspicuous enamel lesions in a mandibular left first molar tooth (309), a clinically visible white spot area containing an enamel lesion in a mandibular left fourth premolar tooth (308), and a root surface caries in the 308 of a different specimen. Histologic examination using special stains and polarized light revealed both initial and early initial stage enamel caries, as well as root surface caries. Knoop hardness measurements confirmed these findings, considered the first documented cases of feline caries.