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Results for “Photogrammetry”

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At least 19 recordsLinked to original sources
PubMed2026

Clinical accuracy and short-term outcomes of intraoral photogrammetry for complete-arch implant rehabilitation: A retrospective multicentre study on 35 patients.

OBJECTIVES: To evaluate the clinical accuracy and short-term outcomes of complete-arch implant-supported fixed dental prostheses (ISFDPs) fabricated using an intraoral photogrammetry (IPG) based digital workflow in completely edentulous patients. METHODS: This multicenter retrospective clinical study included 35 patients rehabilitated with 52 complete-arch ISFDPs (10 FP1, 18 FP2 and 24 FP3 restorations) supported by 221 implants. All definitive prostheses were designed and fabricated using a fully digital workflow initiated by IPG acquisition with the Aoralscan Elite IPG® (SHINING 3D). The primary outcome was clinical accuracy, assessed at definitive prosthesis delivery through evaluation of passive fit using the Sheffield test and radiographic verification. Secondary outcomes included biologic and prosthetic complications, as well as implant and prosthesis survival rates during the follow-up. RESULTS: Passive fit was achieved in all definitive restorations (100%). Radiographic evaluation confirmed accurate marginal adaptation at the implant-prosthesis interface in all cases. No statistically significant differences in clinical accuracy were observed according to treated arch, number of supporting implants, or prosthetic design (P > .05). During a mean follow-up period of 12.1 ± 3.5 months, biologic and prosthetic complications were limited and generally minor. Implant survival was 99.5%, and prosthesis survival was 100%. CONCLUSIONS: Within the limitations of this retrospective clinical study, the IPG based workflow demonstrated high clinical accuracy and predictable short-term outcomes for complete-arch implant rehabilitation, consistently enabling passive fit and favorable prosthetic performance. CLINICAL RELEVANCE: IPG may represent a clinically reliable and predictable approach for complete-arch digital implant impression acquisition. The high rates of passive fit, together with the low incidence of biologic and prosthetic complications observed in this multicenter clinical study, support the use of IPG based workflows for the fabrication of complete-arch ISFDPs.

Humans↗
PubMedDate not supplied

Stereo-photogrammetry for the determination of patient surface geometry.

A stereo-photographic system has been developed with which surface contours of a human subject may be obtained rapidly and objectively. Nonmetric cameras are used and the results are obtained from direct measurements of the photographs. Software has been developed for interpretation of the photographic data with the assistance of a small computer and desk-top digitizer such as those routinely used in radiotherapy treatment planning. With the system the coordinates of a point on the subject may be determined with an accuracy of +/- 1-2 mm.

Computers↗
PubMed1979

Photogrammetry of the optic disc in glaucoma and ocular hypertension with simultaneous stereo photography.

Stereophotogrammetric evaluations of the optic cup were performed for normal, ocular hypertensive, and glaucomatous eyes. Average volume, area, and depth measurements were progressively larger from normal to ocular hypertensive to glaucomatous eyes, although the distributions of individual values exhibited considerable overlap among the three groups. Similar results were obtained for volume, area, and depth asymmetry between each pair of eyes. None of these measurements was able to distinguish accurately between normal and glaucomatous optic cups. However, normal eyes showed a high correlation (r = +0.85) between area and depth of the optic cup, whereas this area/depth relationship was reduced in ocular hypertensives (r = +0.63) and completely broke down for glaucomatous eyes (r = +0.04). Approximately 89% of the glaucomatous eyes and 47% of the ocular hypertensive eyes were beyond the range of normal area/depth correlation values. These findings represent an improvement over most previous attempts to quantitatively differentiate between normal and glaucomatous eyes on the basis of optic disc measurements alone, and support the hypothesis that optic disc damage usually precedes visual field loss in glaucoma. With further technical refinements such as computer image processing, stereophotogrammetry of the optic cup may become a valuable differential diagnostic technique for glaucoma.

Glaucoma↗
PubMed1978

Applied X-ray photogrammetry in neurosurgery.

The introduction of X-ray stereophotogrammetry into neurosurgery permits the exact localisation of metal-dense foreign bodies, the spatial representation of cerebral tumours and their blood supply. The determination of the target point in stereotactic operations is carried out after adjustment of the reference points on the X-ray picture directly by the computer, the seat of the probe can be seen in the X-ray picture in its spatial relations. For intracranial aneurysms, the position, the size, and the topographic situation of the neck of the aneurysm can be determined, and thus the placing of the clip during the operation can be pre-planned and made simpler and safer. A description of the photographic technique and the interpretation by means of the new stereocomparator of Messrs. Zeiss is given.

Humans↗
PubMed1979

[Comparative clinical and photogrammetric studies on the marginal periodontium after the use of dentifrices].

A suggestion was made for testing the therapeutic effect of certain substances on gingival inflammation. Gingivitis was induced in 60 subjects by discontinuing of all forms of oral hygiene. Three tooth pastes, one of which was a placebo, were used for the study. Regression of the inflammation was determined with the periodontal indexes and photogrammetry. Photogrammetry appears to be well suited for objective evaluation of the therapeutic value of certain substances.

Dental Plaque↗
PubMed1978

Calculation of surface area and volume of human erythrocytes from scanning electron micrographs.

This article demonstrates that surface and volume measurements of individual human erythrocytes with varying shapes can be obtained from scanning electron micrographic stereopairs using an approach based on established principles of photogrammetry. Instead of calculating the coordinates of several hundred points plotted for each cell, a procedure that proves tedious and time-consuming, we show that a reasonable approximation of cell surface and volume can be achieved from simple geometrical models constructed with a small number of carefully measured points and angles, using a stereocomparator. The values obtained for two normal erythrocytes and for two distorted red cells from a patient with congenital pyruvate kinase deficiency haemolytic anaemia are consistent with available information on the geometry of these cells. Because scanning electron microscopy requires extensive manipulation of the cells, the values obtained cannot be applied to fresh living material, but appear fairly accurate for the purpose of comparison between cells prepared in the same manner.

Anemia, Hemolytic, Congenital↗
PubMed1977

Comparative reproducibility of the digital photogrammetric procedure utilizing three methods of stereophotography.

The reproducibility of digital photogrammetry of optic nervehead photographs taken with the Zeiss fundus camera with Allen stereoseparator, the Donaldson fundus camera, and the Zeiss fundus camera with twin-prism separator were evaluated. Reproducibility of the various quantitative factors was significantly better when the two types of simultantic cups. Larger per cent errors were encountered with shallower optic cups. Substantial improvements in parameter reproducibility were obtained when finer sampling intervals were used during film digitization.

Computers↗
PubMed2026

Effect of Global Postural Re-Education in Individuals With Text Neck Syndrome: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: This study investigated the effect of Global Postural Re-Education (GPR) versus conventional physical therapy in text neck syndrome (TNS). A prospective, single-blinded, parallel-group randomized controlled trial design was used. METHODS: Sixty participants with TNS (aged 18-40&#xa0;years) were randomly assigned to either conventional treatment or GPR plus conventional treatment. Both groups received supervised therapy for three sessions per week over 4&#xa0;weeks. Outcome measures included craniovertebral and shoulder angles assessed by photogrammetry, pain intensity via Visual Analog Scale, and Cervical Range of Motion via a smartphone application (Clinometer). Measured before and after the intervention. RESULTS: Within-group analyses showed significant improvements in pain and CROM in both groups (p&#xa0;<&#xa0;0.001). However, the between-group analysis revealed no superiority of GPR for pain or CROM (p&#xa0;>&#xa0;0.05). In contrast, GPR demonstrated statistically significant superiority in postural correction, with greater improvements in craniovertebral angle (MD: 2.14&#xb0;; 95% CI: 0.69-3.59; p&#xa0;=&#xa0;0.005) and shoulder angle (MD: 3.2&#xb0;; 95% CI: 0.33-6.07; p&#xa0;=&#xa0;0.03), exceeding MCID thresholds and indicating clinically meaningful benefits. However, these findings should be interpreted with caution because of the longer session duration in the GPR group. DISCUSSION: Incorporating Global Postural Reeducation (GPR) into conventional treatment provided significant additional benefits for postural parameters (craniovertebral and shoulder angles) in individuals with text neck syndrome. However, GPR demonstrated no added superiority over conventional treatment alone regarding pain intensity and cervical range of motion outcomes.

Humans↗
PubMed1976

The effect of oral physiotherapy on dilantin gingival hyperplasia.

Gingival hyperplasia was studied in 13 boys with epilepsy living in a state hospital. Boys were selected on the basis of having gingival hyperplasia, having all teeth between cuspids (upper and lower), having no occlusal abnormality and being cooperative. After gingivectomy, regrowth of gingiva was compared around lateral incisors on one side of the mouth having operator-assisted oral hygiene with that around lateral incisors on the other side of the mouth without operator-assisted oral hygiene. Regrowth of tissue was documented by precise photogrammetry. Oral hygiene, gingival inflammation and crevicular fluid were monitored. Less inflammation, less crevicular fluid and less regrowth of gingival tissues occurred around teeth subjected to good oral hygiene. Precise periodic photographic documentation of the clinical status of patients during studies such as this is considered very valuable.

Adolescent↗
PubMed1978

Multiple-slit illumination of the optic disc.

A modification to a photo slit-lamp illuminator adds detail to the human optic disc surface by projecting onto it a pattern of fine parallel lines. These stripes curve as they traverse the disc, and its surface contour is revealed. Application of this technique may improve the reliability of methods used to quantitate disc topography.

Evaluation Studies as Topic↗
PubMed1978

Classification of human cataracts.

A stereoscopic system of lens photography was developed and was applied in the classification of different forms of cataract. Lenses, after surgical extraction, can be classified by a technician, independent of ophthalmological collaboration. This system meets the needs of the laboratory scientist and has been adopted by the Cooperative Cataract Research Group.

Cataract↗
PubMed1979

Optic disc parameters and onset of glaucomatous field loss. I. Methods and progressive changes in disc morphology.

Serial stereoscopic fundus photographs taken in known relationship to the onset of glaucomatous visual field loss on 12 eyes were intermixed with those from 206 age- and race-matched controls and analyzed in randomized masked fashion. Progressive changes in the size, shape, or contour of the disc, and a newly described parameter, thickness of the nerve fiber layer as it crosses the disc rim, were readily apparent by the time of onset of glaucomatous field loss in all but two abnormal eyes (one case). In the latter instance, direct comparison of stereophotos indicated progressive pallor of the remaining disc tissue. Serial stereophotographs appear superior to fundus drawings for anticipating glaucomatous field loss.

Glaucoma↗
PubMed1979

Optic disc parameters and onset of glaucomatous field loss. II. Static screening criteria.

Stereoscopic fundus photographs of 17 abnormal eyes, taken in known temporal relationship to the onset of glaucomatous visual field loss, and 206 eyes of age- and race-matched controls were examined in randomized masked fashion. Width of the narrowest remaining disc rim, size of the vertical and horizontal physical cups, contour of the temporal and nasal slopes (vertical ovalness), and a newly described parameter, thickness of the nerve fiber layer as it crosses the disc rim, were all useful for distinguishing patients with impending or established visual field loss. None, however, was as effective as defects in the nerve fiber layer, the only parameter displaying sufficient promise as a clinical screening tool to warrant initiation of large-scale prospective evaluation.

Glaucoma↗