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Biomedical subjects

P Nummikoski

Publications and source records attributed to P Nummikoski.

14 recordsLinked to original sources
PubMed1997

A feasibility study evaluating rhBMP-2/absorbable collagen sponge for maxillary sinus floor augmentation.

This 16-week open-label study assessed the safety and technical feasibility of implanting human recombinant bone morphogenetic protein-2 delivered on an absorbable collagen sponge (rhBMP-2/ACS) for two-stage maxillary floor sinus augmentation. This first use of rhBMP-2/ACS in human clinical maxillary sinus floor augmentation included 12 patients with inadequate bone height in the posterior maxilla. The total delivered dose of rhBMP-2 implanted varied from 1.77 to 3.40 mg per patient. The rhBMP-2/ACS device was easily handled. Significant bone growth was documented by computerized tomographic scans in all evaluable patients (11/12). The overall mean height response for the maxillary sinus floor augmentation was 8.51 mm (95% confidence interval 6.07 to 10.95). There were no serious or unexpected immunologic or adverse effects and no clinically significant changes in complete blood counts, blood chemistries, or urinalysis results. The most frequent adverse effects were facial edema, oral erythema, pain, and rhinitis. Eleven patients have received dental implants and follow-up examinations are still being conducted. Histologic examinations of core bone biopsies obtained at the time of dental implant placement confirmed the quality of the bone induced by rhBMP-2/ACS. These results tend to indicate that rhBMP-2/ACS may provide an acceptable alternative to traditional bone grafts and bone substitutes for maxillary sinus floor augmentation procedures in humans.

Absorbable Implants↗
PubMed1997

A feasibility study evaluating rhBMP-2/absorbable collagen sponge device for local alveolar ridge preservation or augmentation.

This two-center human clinical trial evaluated recombinant human bone morphogenetic protein-2 delivered in an absorbable collagen sponge (rhBMP-2/ACS) for either alveolar ridge preservation after tooth extraction or augmentation of localized osseous defects. This 24-month study comprised two parts: a 4-month acute safety and bone induction period (Part I) followed by a 20-month, osseointegration, functional restoration, and long-term safety evaluation (Part II). The primary objective of Part I, discussed in this article, was to evaluate the short-term safety and technical feasibility of the rhBMP-2 device implantation. Twelve patients (six preservation and six augmentation) were enrolled in the investigation. Patient safety was monitored by oral examinations, radiographs, and the collection of blood samples to measure serum chemistries, hematology, and potential antibody formation. Technical feasibility was evaluated by collecting information relating to the handling properties of the rhBMP-2/ACS device. The ability of various evaluative tools to measure the bone-inducing activity of the rhBMP-2/ACS device was also assessed. The clinical results suggested that rhBMP-2/ACS was well tolerated locally and systemically, with no serious adverse events. The device was found to be easily handled and adapted to the ridge and extraction socket. Using direct measurements, all sites demonstrated firmness and fullness to palpation at 4 weeks; however, a loss of volume was noted in some treatment areas between 4 and 8 weeks. Augmentation of the alveolar ridge was not observed in the patients as assessed by the evaluation techniques. This trial indicated that the use of rhBMP-2/ACS to preserve alveolar ridge after tooth extraction or augmentation of localized defects is safe and feasible. Bone fill was observed in all alveolar sockets filled with the rhBMP-2 device.

Absorption↗
PubMed1996

Geometric analysis of occlusal plane orientation using simulated ear-rod facebow transfer.

PURPOSE: Ear-rod facebow techniques may position casts high or low between the upper and lower members on the articulator when using orbitale or nasion as anterior reference positions. This study assessed the effect of changing the anterior reference position on simulated mountings utilizing simulated ear-rod facebow. MATERIALS AND METHODS: Tracings from latoral cephalographs made on seven subjects were superimposed with an outline model of a semiadjustable articulator. Three simulated mountings were performed for each subject in which the plane of occlusion was positioned (1) high, (2) midway, and (3) approaching the lower member (low). Maxillary and mandibular occlusal planes representing intercuspal position were determined from the cephalographs and positioned on the articulator model in a simulated centric relation position for each mounting. Condylar guidance was determined from a simulated protrusive position. RESULTS: Analysis of the three mounting positions demonstrated no change in intercuspal position within subjects; however, angles formed between upper member and condylar guidance were 14.9% smaller for the mid-distance mounting, 42.9% smaller for the high mounting, and 13.4% higher for the low mounting positions when compared with a standard Frankfort horizontal plane reference. CONCLUSIONS: The cephalographs showed extreme variability in the position of the ear piece to bony structures of the skull, but this deviation appeared to be compensated by a change in the horizontal condylar guidance relative to mounting. Results also suggest that casts may be mounted in a convenient mid-position for routine articulation.

Cephalometry↗
PubMed1996

Quantitative analysis of periodontal defects in a skull model by subtraction radiography using a digital imaging device.

This paper describes a quantitative study of periodontal defects produced in a skull model using subtraction images obtained with a digital imaging device, radiovisiography (RVG). Analysis using radiovisiography was compared to changes in weight and volume determined by physical measurements. Four types of periodontal defects were studied: 2-wall, 3-wall, crater, and furcation. All defects were fabricated on posterior teeth in alveolar bone and done with triplicate samples. Defects were made progressively larger in approximately 1 mm steps allowing examination of defects ranging from 1 mm to 5 mm. Radiographic images before and after each step were obtained with a radiovisiography system and subtracted. Changes in weight and defect volume were also recorded and compared to the results obtained after each step from the digital subtraction. For each defect type, a regression analysis was performed to compare changes in bone mass determined by weight with calculated bone loss determined by subtraction radiography or by volume measurements. When the calculated bone losses were compared to the true bone losses it was evident that the subtraction method frequently, but not always, underestimated the lesion sizes. For all lesions the average underestimation was 22%. The largest underestimation occurred with furcation lesions where the measured bone loss was underestimated on average by 67%. Two-walled lesions were underestimated by 30%, 3-wall lesions by 3%, and crater lesions were overestimated by 10%. Furthermore, the accuracy of each 1 mm step in bone loss varied considerably. At present, the imaging system is not sufficiently accurate to establish absolute determinations of the bone loss, but would be clinically useful in determining relative changes in bone loss or gain after treatment. In addition, caution must be taken in interpreting a given change in calculated bone loss, since considerable variation may result in either underestimation or overestimation of bone loss.

Alveolar Bone Loss↗
PubMed1994

Clinical comparison of two panoramic modalities and posterior bite-wing radiography in the detection of proximal dental caries.

A clinical study was designed to examine whether the Philips OrthOralix SD (Gendex Dental Systems, Monza, Italy) orthogonal panoramic projection could improve diagnostic accuracy over standard projections in the detection of proximal surface caries. Thirty-five sets of radiographs that demonstrated optimal image characteristics were selected. Using a five-point scale, 18 viewers evaluated whether specified lesions were present or absent. Viewer data was then compared with a consensus radiographic assessment of the state of the proximal areas. Receiver operating characteristic curves were generated with the use of a maximum-likelihood method of fit. The area under the receiver operating characteristic curve was used as the index of diagnostic accuracy. The mean receiver operating characteristic areas for orthogonal and standard projection panoramic and bite-wing radiography to detect the presence of proximal dental caries were 0.68 +/- 0.03, 0.69 +/- 0.03, and 0.79 +/- 0.03 respectively. Critical ratio analysis was used to compare the means for all possible pairings of imaging modalities. In overall performance, conventional bite-wing radiographs gave a significantly greater diagnostic yield for proximal caries than the Philips OrthOralix SD orthogonal or standard panoramic modalities (p > 0.05). The orthogonal projection did not improve diagnostic accuracy in the detection of proximal carious lesions compared with the standard projection.

Dental Caries↗
PubMed1993

Radiographic interproximal angulations: implications for rotational panoramic radiography.

Axial radiographs were taken on 160 subjects at the screening clinic of the Dental School, University of Texas Health Science Center at San Antonio. Intermeatal and midsagittal lines, together with coordinate axes and polynomial curves that represent the average dental arch form, were overlaid on each radiograph. Coordinate references for interproximal tangents at 3154 contacts along the average dental arch form were digitized and angulations between the arch form and midsagittal plane calculated. Interproximal angulations at the average arch form were found to vary greatly but the average fluctuated around 90 degrees over the length of the arch. Optimal beam angulations were shown to be considerably different from central ray angulations of current panoramic machines, and although most machines demonstrated favorable interproximal beam angulation in the anterior region, discrepancy in the premolar region ranged from 15 degrees to over 40 degrees. Overall the OrthOralix SD (Gendex Dental Systems, S.r.l., Monza, Italy) orthogonal projection and PM 2002 CC (Planmeca Inc. Helsinki, Finland) deviate least from optimal interproximal angulation over most of the dental arch. However, the Planmeca gives a better angulation in the canine/premolar region, whereas the OP5/10 (Palomex Instrumentarium Corp., Helsinki, Finland) is comparable with the OrthOralix SD in the molar region.

Analysis of Variance↗
PubMed1992

Direct digital radiography for the detection of periodontal bone lesions.

In this study the diagnostic accuracy of D-speed and E-speed film in the detection of simulated periodontal bone lesions was compared with that of an electronic direct digital image receptor. Lesions of increasing depth were created in 11 human hemimandibles at the buccal cortical plate in the interproximal marginal bone area by means of 1.4 mm diameter round bursa. Specimens were imaged at each lesion stage with the use of all three receptors. Nine viewers used a 5-point rating scale to evaluate whether lesions were present or absent in the resulting images. Receiver operating characteristic curves were generated, and maximum-likelihood curve areas were calculated. The area under the curve was used as the index of diagnostic accuracy. The mean receiver operating characteristic areas for D-speed film, E-speed film, and the direct digital system were 0.745 +/- 0.038, 0.740 +/- 0.038, and 0.741 +/- 0.037, respectively. Critical ratio analysis was used to compare the means. No statistical difference was found between any of the three image receptors (p > 0.05) for the detection of simulated periodontal lesions 1.0 to 3.0 mm in depth, which suggested that the digital system performed comparably with conventional film systems.

Alveolar Bone Loss↗
PubMed1989

Standard forms of dentition and mandible for applications in rotational panoramic radiography.

Mathematical expressions describing the average form and size of the dentition and the mandible are presented. These expressions should be of value in applications of panoramic radiography when reference to an average standard jaw form is of interest. Data were collected from axial radiographs of 35 males and 35 females of three ethnic groups: Mexican-Americans, black Americans and American and Scandinavian Caucasians. Curves were traced on the axial radiographs representing the dentition and the mandible and points along these curves digitized. Mathematical expressions were established using advanced algorithms for orthogonal polynomial curve fitting, i.e. perpendicular distances to the curved dentition and mandible were minimized rather than distances parallel to the y-axis in an arbitrarily chosen coordinate system. The standard deviations around the polynomials defining the average curves are demonstrated and expressions for calculating the continuously varying standard deviations are given.

Dentition↗
PubMed1988

Dental and mandibular arch widths in three ethnic groups in Texas: a radiographic study.

The dimensions of the dental and mandibular arches were determined in 210 subjects belonging to Mexican American, black American, and white American ethnic groups. The measurements were taken from axial radiographs in which it was possible to trace the intrabony structures of the dentition and the position of the condyles. The study revealed that ethnic and sexual differences in the dental and mandibular arch widths were statistically significant. Males were 0.6 to 1.1 mm wider in their dentitions than females. Mexican Americans had the widest dental arch, although theirs was only 0.2 mm wider than black Americans. White Americans were significantly different; their dental arch was measured as 0.8 to 1.2 mm narrower than that of the other ethnic groups.

Adult↗
PubMed1979

Effect of caries in mentally handicapped children of addition of fluoride and bicarbonate-phosphate to dietary sugar products.

Mentally handicapped children, aged 5--15 years and living in institutions, received fluoride supplement in several sugar products of their diet; in candies, marmalades, jams, fruit juices and in sweet desserts corresponding to 10 mg F as NaF per kg of the sugar (sucrose or glucose) of each product. To two of the four daily candies was also added a NaHCO3 + KH2PO4 mixture (mole ratio 9.8/l, resp.) to substitute for 2.5% of the sugar of the candy. The control children received the respective products without the additives. After stepwise exclusions of subjects for various reasons, e.g. for the absence of permanent teeth, low initial caries activity, strong medication, Down's syndrome, etc., the mean DMFS-increment in the remaining 43 control subjects was 4.5 and in the 41 test subjects 2.6 lesions/100 surfaces at risk, i.e. 42% reduction. Caries arrestment had occurred in these test subjects after the first year, while in the respective controls it was continuously increasing. Among numerous oral and body parameters studied, only surface enamel fluoride in primary teeth was increased by the fluoride supplements and urinary phosphate and calcium excretion decreased.

Adolescent↗
PubMed1976

The effect of magnesium and fluoride on nephrocalcinosis and aortic calcification in rats given high sucrose diets with added phospnates.

The study was conducted to observe in rats the possible modification of ectopic calcification by magnesium-orthophosphate-fluoride combinations, used as additives of diet for reduction of the cariogenicity of the sucrose. In rats, fed low magnesium diets, extra dietary orthophosphate (2%) considerably elevated the calcification of kidneys. Further additions of magnesium and fluoride partially reduced this adverse effect of phosphate. While the calcium content of the aorta in rats, fed low magnesium-high phosphate diet, was considerably elevated, the further addition of magnesium (40 ppm) partially reduced the calcifying effect of phosphate in aorta. Fluoride (15 ppm) together with magnesium (40 ppm) completely reduced it. The appearance of renal calculi caused by a low magnesium diet or by extra phosphate were similar according to light and electron microscopy except for the larger size in the latter case and occasional extratubular calculi found in groups with high phosphate-low magnesium and high phosphate with added magnesium diets.

Animals↗