Abstract Statement of problem As digital impressions become more common and more digital impression systems are released onto the market, it is essential to systematically and objectively evaluate ...their accuracy. Purpose The purpose of this in vitro study was to evaluate and compare the trueness and precision of 6 intraoral scanners and 1 laboratory scanner in both sextant and complete-arch scenarios. Furthermore, time of scanning was evaluated and correlated with trueness and precision. Material and methods A custom complete-arch model was fabricated with a refractive index similar to that of tooth structure. Seven digital impression systems were used to scan the custom model for both posterior sextant and complete arch scenarios. Analysis was performed using 3-dimensional metrology software to measure discrepancies between the master model and experimental casts. Results Of the intraoral scanners, the Planscan was found to have the best trueness and precision while the 3Shape Trios was found to have the poorest for sextant scanning ( P <.001). The order of trueness for complete arch scanning was as follows: 3Shape D800 >iTero >3Shape TRIOS 3 >Carestream 3500 >Planscan >CEREC Omnicam >CEREC Bluecam. The order of precision for complete-arch scanning was as follows: CS3500 >iTero >3Shape D800 >3Shape TRIOS 3 >CEREC Omnicam >Planscan >CEREC Bluecam. For the secondary outcome evaluating the effect time has on trueness and precision, the complete- arch scan time was highly correlated with both trueness (r=0.771) and precision (r=0.771). Conclusions For sextant scanning, the Planscan was found to be the most precise and true scanner. For complete-arch scanning, the 3Shape Trios was found to have the best balance of speed and accuracy.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The development of 3D technology and the trend of increasing the use of intraoral scanners in dental office routine lead to the need for comparisons with conventional techniques.
To determine if ...intra- and inter-arch measurements from digital dental models acquired by an intraoral scanner are as reliable and valid as the similar measurements achieved from dental models obtained through conventional intraoral impressions.
An unrestricted electronic search of seven databases until February 2015.
Studies that focused on the accuracy and reliability of images obtained from intraoral scanners compared to images obtained from conventional impressions.
After study selection the QUADAS risk of bias assessment tool for diagnostic studies was used to assess the risk of bias (RoB) among the included studies.
Four articles were included in the qualitative synthesis. The scanners evaluated were OrthoProof, Lava, iOC intraoral, Lava COS, iTero and D250. These studies evaluated the reliability of tooth widths, Bolton ratio measurements, and image superimposition. Two studies were classified as having low RoB; one had moderate RoB and the remaining one had high RoB. Only one study evaluated the time required to complete clinical procedures and patient's opinion about the procedure. Patients reported feeling more comfortable with the conventional dental impression method.
Associated costs were not considered in any of the included study.
Inter- and intra-arch measurements from digital models produced from intraoral scans appeared to be reliable and accurate in comparison to those from conventional impressions. This assessment only applies to the intraoral scanners models considered in the finally included studies. Digital models produced by intraoral scan eliminate the need of impressions materials; however, currently, longer time is needed to take the digital images.
PROSPERO (CRD42014009702).
None.
Genetic and environmental factors are essential in occlusal variations and malocclusion and have been of considerable interest to orthodontists. Studies on twin pairs are one of the most effective ...methods for investigating genetically determined occlusal variables. Many studies have focused on distances between first molars or between canines but malocclusions can also occur in other regions of the dental arch. Aim: To evaluate the characteristics of the dental arch between pairs of Monozygotic (MZ) and Dizygotic (DZ) twins from Southern India. Methods: A random sample of 51 twin pairs (12–18years old) participated in this study. The zygosity of twin pairs was recorded by facial appearance. The occlusion of the first permanent molars was recorded according to Angle’s classification. Study models were prepared to assess dental arch characteristics (i.e., arch form, arch perimeter, arch length; intercanine, intermolar width, and teeth size discrepancy). The obtained data was statistically analyzed using SPSS software 19.0. The student’s t-test (two-tailed, independent) and Chi-square test was used to determine the significance of studied parameters. Results: Angle’s Class I molar relation was more commonly observed followed by the Class II molar relationship among twins. The measured dental arch dimensions did not show a statistically significant difference among twin pairs. The ovoid arch form was commonly observed among Monozygotic and Dizygotic Twins. There was a similarity among MZ and DZ twins in the anterior and overall Bolton’s ratio. Conclusion: There were similar occurrences of measured parameters among twins, which showed genetic predominance in the expression of measured dental arch traits.
•An automatic reconstruction method for high-contrast panoramic image from dental CBCT data is proposed.•The thickness detection of the dental arch effectively overcomes the inaccuracy of the manual ...setting and reduces the non-interesting tissues in panoramic image reconstruction.•The method proposes a new synthesis algorithm that can effectively improve the contrast of panoramic images.•An image enhancement algorithm is applied to improve the detail contrast of the final panoramic image.•The method could automatically and reliably improve the global and detail contrast of the panoramic image generated from dental CBCT data.
Panoramic images reconstructed from dental cone beam CT (CBCT) data have been effectively used in dental clinics for disease diagnosis. Panoramic images generally have low contrast because excessive non-interest tissues participate in the reconstruction, which may affect the diagnosis. In this study, we developed a fully automatic reconstruction method to improve the global and detail contrast of panoramic images.
The proposed method consists of dental arch thickness detection, image synthesis, and image enhancement. First, the dental arch thickness is detected from an axial maximum intensity projection (MIP) image generated from the axial slices containing the teeth to reduce non-interest tissues in panoramic image reconstruction. Then, a new synthesis algorithm is proposed at image synthesis stage to reduce the effect of non-interest tissues on image contrast. Finally, an image enhancement algorithm is applied to the synthesized image to improve the detail contrast of the final panoramic image.
A total of 129 real clinical dental CBCT data sets were used to test the proposed method. The panoramic images generated by three methods were subjectively scored by three experienced dentists who were blinded to the generated method. The evaluation of image contrast included the maxillary, mandible, teeth, and particular region (root canal, crown reconstruction, implants, and metal brackets). The overall image contrast score revealed that the proposed method scored the highest of 11.03 ± 2.46, followed by the ray sum and x-ray methods with corresponding scores of 6.4 ± 1.65 and 5.35 ± 1.56. The results of expert subjective scoring indicated that the image contrast of the panoramic image generated by the proposed method is higher than those of existing methods.
The proposed method provides a quick, effective and robust solution to improve the global and detail contrast of the panoramic image generated from dental CBCT data.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To analyze the buccal bone thickness, bone depth, and cortical bone depth of the mandibular buccal shelf (MBS) to determine the most suitable sites of the MBS for mini-screw insertion.
The sample ...included cone-beam computed tomographic (CBCT) records of 30 adult subjects (mean age 30.9 ± 7.0 years) evaluated retrospectively. All CBCT examinations were performed with the i-CAT CBCT scanner. Each exam was converted into DICOM format and processed with OsiriX Medical Imaging software. Proper view sections of the MBS were obtained for quantitative and qualitative evaluation of bone characteristics.
Mesial and distal second molar root scan sections showed enough buccal bone for mini-screw insertion. The evaluation of bone depth was performed at 4 and 6 mm buccally to the cementoenamel junction. The mesial root of the mandibular second molar at 4 and 6 mm showed average bone depths of 18.51 mm and 14.14 mm, respectively. The distal root of the mandibular second molar showed average bone depths of 19.91 mm and 16.5 mm, respectively. All sites showed cortical bone depth thickness greater than 2 mm.
Specific sites of the MBS offer enough bone quantity and adequate bone quality for mini-screw insertion. The insertion site with the optimal anatomic characteristics is the buccal bone corresponding to the distal root of second molar, with screw insertion 4 mm buccal to the cementoenamel junction. Considering the cortical bone thickness of optimal insertion sites, pre-drilling is always recommended in order to avoid high insertion torque.
The study aimed to compare the trueness and precision of five intraoral scanners (Emerald S, iTero Element 5D, Medit i700, Primescan, and Trios 4) and two indirect digitization techniques for both ...teeth and soft tissues on fresh mandibular and maxillary cadaver jaws.
The maxilla and mandible of a fully dentate cadaver were scanned by the ATOS industrial scanner to create a master model. Then, the specimens were scanned eight times by each intraoral scanner (IOS). In addition, 8 polyvinylsiloxane (PVS) impressions were made and digitized with a Medit T710 desktop scanner. Stone models were then poured and again scanned with the desktop scanner. All IOS, PVS, and stone models were compared to the master model to calculate the mean absolute surface deviation for mandibular teeth, maxillary teeth, and palate.
For mandibular teeth, the PVS trueness was only significantly better than the Medit i700 (p < 0.001) and Primescan (p < 0.05). In maxillary teeth, the PVS trueness was significantly better than all IOSs (p < 0.05-0.001); the stone trueness was significantly better than Emerald S (p < 0.01), Medit i700 (p < 0.001) and Primescan (p < 0.01). In the palate, PVS and stone trueness were significantly lower than the iTero Element 5D (p < 0.01) and Trios 4 (p < p < 0.01). Stone trueness was significantly lower than the Medit i700 (p < 0.05). The precision in the palate was significantly lower for PVS and stone than for Emerald S (p < 0.01, p < 0.05), iTero Element 5D (p < 0.01, p < 0.01), Primescan (p < 0.001, p < 0.001), and Trios 4 (p < 0.001, p < 0.01). Significant differences in trueness between the IOSs were observed only in the mandibular teeth. The Medit i700 performed worse than Emerald S (p < 0.01) and iTero Element 5D (p < 0.01). For mandibular teeth, the Medit i700 was significantly more precise than Primescan (p < 0.01) and the Emerald S (p < 0.05). The Trios 4 was significantly less precise than Emerald S (p < 0.05). The precision of Medit i700 was significantly worse than iTero Element 5D (p < 0.01) for maxillary teeth, as well as the Primescan (p < 0.01) and Trios 4 (p < 0.05) for the palate.
In general, indirectly digitized models from PVS impressions had higher trueness than IOS for maxillary teeth; precision between the two methods was similar. IOS was more accurate for palatal tissues. The differences in trueness and precision for mandibular teeth between the various techniques were negligible.
All investigated IOSs and indirect digitization could be used for complete arch scanning in mandibular and maxillary dentate arches. However, direct optical digitization is preferable for the palate due to the low accuracy of physical impression techniques for soft tissues.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Introduction Surgically assisted mandibular arch expansion is an effective treatment modality for alleviating constriction and crowding. However, only mandibular symphyseal osteotomy is recommended ...for mandibular arch expansion. No relevant studies have compared the biomechanical responses of different corticotomy designs on mandibular expansion. Therefore, the aim of this study was to evaluate the effect of different corticotomy approaches and modes of loading on the expansion of adult mandibles using biomechanics. Methods Nine finite element models including 2 novel corticotomy designs were simulated. Stress, strain, and displacement of crown, root, and bone were calculated and compared under different corticotomy approaches and loading conditions. Results The biomechanical response seen in the finite element models in terms of displacement on the x-axis was consistent from anterior to posterior teeth with parasymphyseal step corticotomy and tooth-borne force application. In addition, the amount of displacement predicted by parasymphyseal step corticotomy in the tooth-borne mode was greater compared with other models. Conclusions These results suggest that parasymphyseal step corticotomy with tooth-borne force application is a viable treatment option for true bony expansion in an adult mandible.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Purpose: This study was conducted to investigate the dental and palatal arch dimensions of male and female siblings in relation to gender and age, using three-dimensional (3D) digital casts.Methods: ...This study involved 54 subjects (27 pairs) of male-female siblings aged 15 to 45 years. Dental casts were digitized and analyzed for tooth size (TS), arch width (AW), arch length (AL), arch length discrepancy (ALD), and palatal arch dimensions (PAD). The data obtained were subjected to t-tests, and the palatal curvature (PC) was modeled using a fourth-order polynomial.Results: Significant differences (P < 0.05) between the sexes were found in the mesiodistal TS, particularly in all canines, as well as 16, 36, 46, and 41. Maxillary AW and AL were also significantly (P < 0.05) influenced by sexes. Most arch parameters were more prominent in male siblings, and the effect of age on PC differed between the sexes. In addition, the PC of adolescent females was mostly superimposed on adult females relative to males.Conclusion: Among siblings, males were found to have significantly larger dental arch dimensions than females. Furthermore, PC showed some differences between the sexes in both the frontal and sagittal planes.
ABSTRACT
Background: The quality of bone is an important factor in the successful implant treatment, and it is evident that higher implant failure is more likely in poor quality of bone. The primary ...stability of oral implants related to resistance to micromotion during healing is influenced by bone quality, surgical technique, and implant design.
Purposes: The aims of this biomechanical study were to explore the effect of bone quality on initial intraosseous stability of implants, and to determine the correlations between the bone quality and implant stability parameters.
Materials and Methods: Twenty‐four implants (Neoss Ltd., Mölnlycke, Sweden) were placed into anterior and posterior regions of three human cadaver mandibles. The bone densities of implant recipient sites were preoperatively determined using computerized tomography (CT) in Hounsfield unit (HU). The maximum insertion torque values were recorded, and primary implant stability measurements were noninvasively performed by means of resonance frequency analysis (RFA).
Results: The bone density values ranged from −267 HU to 553 HU. It was found that mean bone density, insertion torque, and RFA values were 113 ± 270 HU, 41.9 ± 5 Ncm, and 70 ± 7 implant stability quotient (ISQ), respectively. Statistically significant correlations were found between bone density and insertion torque values (r = 0.690, p < .001); bone density and ISQ values (r = 0.557, p < .05); and insertion torque and ISQ values (r = 0.853, p < .001).
Conclusion: CT is a useful tool to assess bone quantity and quality in implant recipient sites, and bone density has a prevailing effect on implant stability at placement.
Full text
Available for:
BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
