Is the glass half empty or half full? A novel "philosophical" approach to the "mystery" of the so-called ferrule effect.

The prognosis of endodontically treated teeth has traditionally been associated with the presence of the so-called ferrule effect that is generally related with the presence of a minimum of 1-2 mm of sound tooth structure at the cervical area of parallel axial walls that totally encircle the tooth. Even though all of these factors are well desired, one should question if their absence should condemn a tooth and compel extraction as the only logical treatment plan option. For this reason an hypothesis is being formed that associates the aforementioned factors not with the presence of the so-called ferrule effect, but rather with the resistance form of the preparation that is being provided by the sound tooth structure at the cervical area of the tooth. When the desired resistance form is provided by sound tooth structure of endodontically treated teeth, then less lateral forces are being transferred to the post & core and subsequently to the root of the teeth, thus minimizing the chances of decementation of the post & core or worst fracture of the root. Even more important, if this hypothesis may be further entertained, then even when the so-called ferrule effect is not present, the teeth may not be extracted, but alternative strategies for post & core restorations may be investigated, such a more flexible carbon- or glass-fiber posts & core build ups made from flowable resin composite that may accommodate for the increased lateral forced exerted to the post & core complex during function.

A Novel Method of Capturing Fluorescence in Clinical Dentistry.

OBJECTIVES: A fully integrated esthetic restoration should emit levels of fluorescence similar to that of natural dentition. Also, dental practitioners should be able to monitor this property in their routine clinical setting. The aim of this study was to investigate the efficacy of a removable filter for a macro flash illumination set-up required for the digital photographic recording of the fluorescence emission of human teeth and dental restorations. METHODS: The traditional fluorescence capturing method in clinical dentistry, using continuous lighting, was compared with the proposed flash lighting method. A digital single-lens reflex Canon 550D camera with a Canon 100-mm macro lens and a commercially available standard Canon MT-24EX twin light macro flash were used in this study. A custom-fabricated plastic o-ring was fixed with silicone to the original flash framework, which received a removable fluorescence filter composed of two 365-nm ultraviolet (UV) glass filters on both sides, covering the flash lamps. The original protective plastic diffusers in front of the flash lamps were replaced with clear plastic to release the full excitation wavelength range of the xenon flash lamps. No additional filter was placed in front of the lens. RESULTS: The results showed that using the proposed custom-made flash/filter illumination source, f-numbers between 16 through 22, a shutter speed of 1/60, and ISO 800 or 1600 sensitivity settings attained satisfactory fluorescent digital images. Results were comparable to those accomplished using a traditional photographic technique, without the need for a dark room, extended exposure times, and time-consuming set-ups. CONCLUSION: A contemporary photographic technique was demonstrated using macro flash UV-A 365-nm illumination that allowed fluorescent digital photograph acquisition under standard dental office conditions. Fluorescence documentation using a quick, straightforward procedure can take place during the restorative session to help increase the success rate of dental restorations.

Digital Photographic Procedure for Comprehensive Two-Dimensional Tooth Shade Analysis.

Current commercially available restorative materials vary in their esthetic properties, depending on brand and shade. Variations are related not only to basic color parameters such as hue, chroma, and value, but also to other important properties that affect the overall esthetic restorative outcome, such as opalescence, fluorescence, translucency, and metamerism. Fluorescence and bluish opalescence, though associated with the ingredients and chemical composition of the material, may be controlled and refined by a proper layering technique if that pretreatment analysis has been performed with the aid of appropriate photographic techniques. Digital cameras and dental photography have long been imperative tools for clinicians in their daily practice. Traditionally, digital photography has been used for recordkeeping, documentation, presentation, and informing patients of their oral status before and after treatment. Today, evolved techniques facilitate clinicians' ability to compare the esthetic properties of restorative materials with those of natural teeth for delivery of natural-looking restorations. Moreover, documentation obtained before and after restoration may be used for more comprehensive information for the patient.