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.

[Erosion. Clinical aspects--diagnosis--risk factors--prevention--therapy]. / Erosionen. Befund--Diagnose--Risikofaktoren--Prävention--Therapie.

Dental erosions have a multifactorial genesis. Acids of intrinsic and extrinsic origin are thought to be the main aetiologic factors, but also abrasive components can be involved in tooth destruction. This overview gives information about the clinical appearence and the risk factors for the developement of erosive lesions. In addition, preventive and therapeutic measures are discussed. The knowledge about the patient's history, the accurate clinical examination and the correct diagnosis are prerequisites for an adequate preventive and therapeutic concept. It is important to get data about diet habits and host factors like salivary flow rate, buffering capacity and pH as well as intrinsic factors like the occurence of gastroesophageal reflux or vomiting. A novel scheme showing the dependences of the different risk factors is given. To determine the patient's individual risk for erosion, the dentist must be able to assess the erosive potential of these parameters. Data about the distribution and clinical appearance of erosive defects, photographs and study casts are important to plan the prevention and therapy and to judge the success of such measures.

Effects of bone morphogenetic protein-2 and hyaluronic acid on the osseointegration of hydroxyapatite-coated implants: an experimental study in sheep.

Research efforts aim at enhancing early osseointegration of cementless implants to improve early fixation and, thus, reduce the risk of loosening. The aim of the present study was to investigate whether bone morphogenetic protein (BMP) 2 had a positive effect on the osseointegration of hydroxyapatite-coated implants. Hydroxyapatite (HA) implants (perforated hollow cylinders and solid rods) were coated with BMP-2 and hyaluronic acid (HY) as the carrier or with HY alone. Uncoated HA implants served as controls. The osseointegration of the implants was evaluated either by light microscopy or by pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 24 sheep. The BMP-2 coating significantly increased bone growth into the implant perforations compared with HA-coated implants at 2 and 4 weeks. Bone-implant contact and interface shear strength of BMP-2 implants were lower than HA implants at 2 weeks. At 4 weeks, there was no significant difference in bone-implant contact and shear strength between BMP-2 and HA-coated implants. The BMP-2 coating enhanced gap healing but had no positive or even an inhibitory effect (at 2 weeks) on bone-implant contact and interface shear strength. In the clinical situation, a perfect press-fit implantation cannot be achieved, and BMP-2 may be beneficial for enhancing bone growth into gaps around cementless implants.

Comparison of chemomechanical caries removal using Carisolv or conventional hand excavation in deciduous teeth in vitro.

OBJECTIVES: The purpose of the present study was to compare the efficacy of chemomechanical caries removal (Carisolv) to conventional hand excavation in deciduous teeth. METHODS: Twenty-two freshly extracted teeth with varying degree of caries were treated using both of these methods. One part of each caries lesion was prepared using the Carisolv method and the other part using conventional hand excavation. The third (middle) part was left untreated to serve as control. Histological preparations of each tooth were then made and examined in order to compare the quality of the preparations. Length and area of residual caries, microhardness of the dentine in each group and time needed for preparation were analysed. RESULTS: The results showed that there was no significant difference in the amount of residual caries in the cavity walls treated using the two methods. CONCLUSIONS: The Carisolv method was significantly more time consuming than conventional preparation using hand excavator. However, both methods removed caries efficiently.

[The balanced force and the GT-rotary technique in comparison with the non-instrumental technique (NIT)]. / Die Balanced Force und die GT-Rotary-Technik im Vergleich zur nicht instrumentellen Technik (NIT).

The aim of the study was to compare the cleansing effect of the latest modification of the non-instrumentation technique (NIT) to that of conventional instrumentation. The root curvature in 100 vital human molars was determined by a standardized X-ray procedure and the teeth were assigned to five groups with 20 teeth each with an equal distribution of the root curvature. The preparation methods were the Balanced Force technique and the GT Rotary technique. Each root was irrigated with 40 ml of 3% sodium hypochlorite. The other groups were irrigated by NIT during 2.5, 5 or 10 minutes, respectively. The remaining pulpal tissue was stained and the root canals were exposed longitudinally. The teeth were then evaluated using a microscope and an image analysis-system. The residual organic debris in the apical, middle and coronal sections of the root canals were assessed as a percentage of the corresponding total examined length. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was significantly better (p < 0.05) compared to using the device for 2.5 minutes. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was also significantly better (p < 0.05) compared to using the GT Rotary or Balanced Force techniques. Apically, the cleansing effect of the NIT used for 5 and 10 minutes and the GT Rotary technique was significantly better (p < 0.05) compared to using the Balanced Force technique or the NIT for 2.5 minutes. It was concluded that the cleansing effect of the latest modification of the Non-instrumentation Technology (NIT) was equivalent to or better than that of conventional instrumentation requiring significantly less time.

Feline dental resorptive lesions in the 13th to 14th centuries.

The Schild excavation (1971-1975) unearthed 1871 feline bones from at least 181 cats from the 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.

In vivo comparison of the osseointegration of vacuum plasma sprayed titanium- and hydroxyapatite-coated implants.

For the last 15 years, orthopedic implants have been coated with hydroxyapatite (HA) to improve implant fixation. The osteoconductive effect of HA coatings has been demonstrated in experimental and clinical studies. However, there are ongoing developments to improve the quality of HA coatings. The objective of this study was to investigate whether a rough and highly crystalline HA coating applied by vacuum plasma spraying (VPS) had a positive effect on the osseointegration of special, high-grade titanium (Ti) implants with the same surface roughness. Ti alloy implants were coated (VPS) with special, high-grade Ti or HA. The osseointegration of the implants was evaluated by either light microscopy or pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 18 sheep. The interface shear strength increased significantly over all time intervals. By 4 weeks, values had reached approximately 10N/mm(2). However, the difference between the coatings was not significant at any time interval. Direct bone-implant contact was significantly different between the coatings after 2 and 4 weeks, and reached 46% for Ti and 68% for HA implants by 4 weeks. This study indicates that the use of a rough and highly crystalline HA coating, applied by VPS, enhances early osseointegration. Accelerated establishment of secondary implant fixation decreases the risk of early loosening.