Lateral alveolar ridge augmentation using a synthetic nano-crystalline hydroxyapatite bone substitution material (Ostim): preliminary clinical and histological results

OBJECTIVES: The purpose of this preliminary two-center clinical prospective study was to evaluate the tissue composition of augmented sites after the use of a nano-crystalline hydroxyapatite (ncHA) bone substitution material by clinical and histological examinations. MATERIAL AND METHODS: A synthetic ncHA augmentation material was used without any additives in 14 patients requiring lateral ridge augmentation 6-7 months before (10 patients) or at implant placement (four patients). The ncHA material was covered by a titanium mesh for space maintenance. Clinical and radiographic parameters were evaluated and bone biopsy cores, obtained 6-7 months following augmentation, were assessed histologically and histomorphometrically. RESULTS: One patient showed gingival swelling, redness and pain at the augmentation site requiring removal of the titanium mesh 6 weeks postoperatively. In seven patients, a premature exposure of the titanium mesh without any inflammatory symptoms was noted. The width of the fixed gingival and the alveolar ridge height did not change significantly at least 6 months following augmentation (P>0.5), whereas a significant gain in alveolar ridge width (P=0.01) was noted. After a median period of prosthetic loading of 24 months, no implant was considered to be a failure. Histology revealed ncHA remnants in peripheral and central parts of biopsy cores obtained from seven patients after at least 6 months without histological symptoms of inflammation, whereas histomorphometry of bone cores revealed no significant differences of the mean percentage area of ncHA in peripheral (23.4%) and central (15.1%) parts of biopsy cores (P=0.262). The mean percentage area of bone colonizing the defect was 52.3%. CONCLUSIONS: Small amounts of ncHA were found after at least 6 months in bone biopsies. The former defect space was filled with bone. The alveolar ridge width gain was found to be significant after lateral augmentation utilizing ncHA, providing a quantitatively and qualitatively sufficient site for primary stable implant placement.     

A case for absolute anchorage

It would be an understatement to say that implant technology has changed the face of dentistry in the past 10 years or so. Both the surgical and restorative specialties have undergone dramatic transformation from treatment planning through all phases of rehabilitation. However, the same cannot necessarily be said for the specialty of orthodontics. Although it could be argued that implants have had an impact on the planning and setup of orthodontic cases (such as in congenitally missing teeth situations), the actual utilization of implants as an integral part of mechanotherapy has only begun to be realized. The ultimate extension of this application of using implants to enhance tooth movement would be to employ implants that are designed solely for the purpose of facilitating orthodontic therapy, with no intention to restore, but rather to explant such implants, after their purpose is fulfilled.     

Calcium hydroxide: the ultimate medicament?

There has been a trend to the promiscuous use of calcium hydroxide in clinical endodontics. It can be concluded that this medicament is not the principal factor in success following its use. It is reasonable to state that endodontic success is related to the obliteration of the canal system with a solid core root canal filling such as gutta percha.     

Development of a novel digital subtraction technique for detecting subtle changes in jawbone density

The objective of this paper is to develop a novel digital subtraction technique for serial intra-oral radiography, which would allow the detection of subtle variations in grey values. Digital images of the maxilla of a dried human skull and of a fresh pig mandible were acquired using intra-oral photostimulable phosphor plates (Digora FMX, Soredex, Helsinki) with an aluminium calibration stepwedge incorporated in the filmholder. Exposures were made with an X-ray tube for intra-oral radiography (Prostyle Intra, Planmeca, Helsinki). During pilot testing, parameter settings were adapted to reach an optimal contrast. Exposures were repeated within a 1-week interval to determine the test-retest reliability of the development. After in vitro and in vivo testing, the exposure technique and software development were used to evaluate its applicability in a pilot clinical case. Although parameter settings remained stable during the in vitro studies, the clinical exposures yielded non-linear digital images, thus, not readily suitable for data acquisition and comparison of the regions of interest. To allow further analysis, image processing was carried out using self-developed software for semi-automated linearisation and optimised contrast normalisation. This processing significantly increased the precise quantisation of jawbone density and the assessment of subtle bone density changes in arbitrarily selected regions of interest of in vivo exposures. The clinical applicability of the technique is demonstrated in a pilot case. It was demonstrated that minute densitometric deviations could be detected. The present technique and image processing may allow the quantification of jawbone density.     

Salivary cortisol levels and dental anxiety in children with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a common developmental disorder. The present study tested the hypotheses that children with ADHD, particularly those exhibiting severe hyperactivity and impulsivity, have a different stress reaction (measured by salivary cortisol) during a dental recall visit and are more dentally anxious than children in a control group. Eighteen children with ADHD and a control group of 71 children, all 13 yr of age, underwent a clinical dental examination and completed the Corah Dental Anxiety Scale (CDAS). Four saliva samples were gathered for analysis of cortisol: one prior to dental examination, one after, and two the following morning. The subgroup ADHD with hyperactivity/impulsivity had statistically significantly lower cortisol levels than the control group 30 min after awakening. When cortisol values were plotted on a timeline, this subgroup always had lower cortisol concentrations than children in the control group. There was a significant correlation between CDAS scores and cortisol concentrations prior to the dental examination in both the ADHD and the control group. Behavioral expressions of anxiety in children with ADHD may be different from those in other children, not only due to the characteristics of their disorder, but also because of lower stress reactivity.     

Rural versus urban analysis of dental procedures provided to Virginia Medicaid recipients

PURPOSE: The purpose of this study was to report the distribution of procedures provided to Virginia Medicaid children by 3 types of dental providers in rural and urban areas. METHODS: Medicaid claims filed for dental patients less than 21 years old were obtained and analyzed for fiscal years 1994-1995. Dental providers were categorized according to their practice type: (1) general practice (GP); (2) pediatric (PD); and (3) public health (PH) dentists. Each type of practice was categorized as practicing in a metropolitan, urban, rural, or completely rural location and evaluated for percentages of preventive, diagnostic, and corrective services provided. RESULTS: Rural areas had a higher percentage of significant providers than did metropolitan or urban areas. General dentists performed more diagnostic and preventive but fewer corrective procedures than pediatric dentists. Pediatric dentists and general dentists in completely rural areas performed more corrective procedures than their counterparts in metropolitan or urban areas. CONCLUSIONS: General, pediatric, and public health dentists in metropolitan and urban areas perform slightly more diagnostic services and fewer corrective services than practitioners in more rural areas.     

Scanning electron microscopic study of the effect of salivary pellicle on enamel erosion

A bovine tooth model system was used to study the effect of experimental salivary pellicle on enamel erosion. Test blocks with varnish-covered control surfaces in each specimen were immersed into an acidic cola beverage (pH 2.6) for 120 min, either with or without the pellicle which was grown for 7 days by using clarified human saliva. After immersion, the pellicle was removed from some specimens with 10% sodium hypochlorite (20 h at 20 degrees C) and ultrasonic bath (60 s) to study its effect on erosion. All specimens were then studied in the scanning electron microscope. The specimens without pellicle (positive controls) showed gross erosion with prism core dissolution in all study blocks. The specimens with pellicle showed occasionally a film-like integument covering the apparently intact test surfaces with adjacent enamel surfaces slightly eroded. The erosion, however, was not of the same magnitude as in the positive controls. After removing the pellicle, the enamel surfaces showed pitted appearance of the prism heads; the demineralization seemed to attack more the prism sheath areas. Thus, salivary pellicle was found to protect the underlining enamel from erosion in vitro.     

Utility of the Dental Aesthetic Index in Industrialized and Developing Countries

To be truly useful, an index must be applicable universally without modification. The data presented in this article support the use of the standard DAI without modification to assess need for orthodontic treatment in both developing and industrialized countries. When students from Thailand, Australia, the German Democratic Republic, and Native Americans residing on Indian reservations rated the same 25 occlusal stimuli (photographs of dental configurations) for dental aesthetics, their ratings of these stimuli when arranged in rank order were highly correlated with those of US students. These 25 occlusal stimuli were a subset of the original 200 occlusal stimuli used in deriving the standard DAI regression equation. This article presents data indicating that when a Native American DAI was derived based on Native American ratings of the same 200 occlusal stimuli used in deriving the standard DAI, the Native American DAI and the standard DAI had the same ten components (orthodontic measurements) and strikingly similar regression coefficients (weights). Further analysis indicated that the two equations were sufficiently similar to justify using the standard DAI to obtain DAI scores on Native Americans and to estimate the relative social acceptability of their dental aesthetics. If ratings for dental aesthetics for the full set of 200 stimuli were available for each of the countries where only 25 were rated, we expect that, as in the case of Native Americans, a country-specific DAI, if computed, would be sufficiently similar to the standard DAI that no modification would be needed to allow use of the standard DAI in that country.(ABSTRACT TRUNCATED AT 250 WORDS)