Ridge Dimensions Research Articles

The validity of different display monitors in the assessment of dental implant site dimensions in cone beam computed tomography images

Objective. To determine if the differing contrast resolution of various LCD monitors affects the reliability or accuracy of measurements of proposed implant sites. Materials and methods. Edentulous areas of human dry skulls were marked with radiopaque markers in order to standardize the plane of the transverse cross-sections of the ridges and path of measurements. The skulls were imaged by a CBCT device and the images stored in proprietary format on the workstation. The data sets were then transferred, with the proprietary reformatting software, to two different laptops using CDs. Transverse cross-sectional images of the ridges were reformatted on all three computers and ridge dimensions were recorded using the linear measurement tool of the proprietary software. Ridge dimensions were recorded directly from the three different monitors by two observers and compared to measurements recorded directly from the bone. The measurement errors and intra- and inter-examiner reliability were calculated for each monitor and compared with each other. Results. Intra- and inter-examiner reliability scores for the measurements recorded from all three devices were very high and ranged between 0.993–0.999. The mean of the absolute errors was 0.55 mm for the workstation, 0.61 mm for laptop 1 and 0.68 mm for laptop 2. The absolute errors were statistically significant for all three monitors (p-value < 0.001), but there was no statistically significant difference between the absolute errors obtained from the three monitors. Conclusions. No differences in the reliability or accuracy of measurements of implant site dimensions were obtained using color LCD monitors with different contrast resolution capabilities.

Uso da membrana de látex em alvéolos de dentes recém-extraídos : relato de caso

The aim of this study was to report a radiographical follow up of the reparation of sockets in recently extracted teeth using latex membranes. A group of systemical healthy patients with indication for extraction of lower right second molar were chosen and latex membrane to stabilize the blood clot on the dental socket were used. These radiographs were taken on pre and post-operative and vertical bone loss was measured. As results a minimization of vertical bone loss was noticed and we conclude that the latex membrane was well tolerated by the patients and helped with the healing and maintenance of the dimensions of the alveolar ridge.

A Prospective, Randomized, Controlled Clinical and Histological Evaluation of Extraction Sites Augmented With Cortical Powder and Cancellous Particulate Allograft

Tooth extraction sites that heal without grafting are often associated with reduction of local bone dimension and volume sometimes leading to implant placement challenges1,2. Although tooth extraction sites heal adequately without intervention, reduction of un-grafted post-extraction ridge dimensions may be problematic for dental implant treatment planning.

A Review on Alveolar Ridge Preservation Following Tooth Extraction

Context The question that clinicians face is whether the use of bone replacement grafts and/or barrier membranes enhance their ability to provide for the future placement of a dental implant or to maximize ridge dimensions following the extraction of a tooth versus no additional treatments.Evidence Acquisition The evidence was obtained by search of Entrez PubMed and manual search of The International Journal of Oral and Maxillofacial Implants, The International Journal of Periodontics & Restorative Dentistry, Clinical Oral Implant Research, The Journal of Periodontology, The Journal of Clinical Periodontology, and The Compendium of Continuing Education in Dentistry. Key search words included Guided Bone Regeneration, Dental Extraction, Tooth Extraction, Bone Replacement Graft, Alveolar Ridge. The years of search included from January 2011 through February 2012.Evidence Synthesis The recurring theme was that there was considerable heterogeneity to study designs, time periods, and methods of evaluation. This created great difficulty in trying to answer with good high-quality evidence questions about the techniques and materials to be used for maximizing regeneration at the time of tooth extraction or in which situations this ought to be used.Conclusions There appears to be consensus from the reviewed literature supporting ridge preservation techniques as a whole. Multiple studies demonstrated less ridge resorption occurring when alveolar ridge preservation procedures were used versus the placement of no graft material in fresh alveolar sockets. The analysis did not show any grafting materials demonstrating a clear benefit over any others or that a barrier membrane is necessary. The evidence is also too premature about whether socket preservation efforts require primary closure. In the emerging area of growth factors, there is no high-quality evidence to either support or refute their use.Background Tooth extraction is one of the most widely performed procedures in dentistry today and it has been historically well documented that this procedure may induce significant dimensional changes of the alveolar ridge. The dilemma that clinicians face is how to manage tooth extractions to provide for the future placement of a dental implant or to maximize ridge dimensions for the fabrication of a fixed or removable prosthesis. If performed inadequately, the resulting deformity can be a considerable obstacle to the esthetic, phonetic, and functional results that both our patients and we clinicians expect at this current time.

도파관 슬롯 배열 안테나용 리지가 장하된 끝이 둥근 소형 슬롯

본 논문에서는 도파관 슬롯 배열 안테나의 요소로서 구형 도파관 광벽에 위치하고 이중 리지가 장하된 끝이 둥근 소형 슬롯을 제안하였다. 리지 치수를 적절히 조절하면 원하는 주파수에서 슬롯의 공진을 얻을 수 있다. 제안된 슬롯의 공진 길이는 공진 주파수에서 약 <TEX>$0.26{\lambda}_0$</TEX>(자유 공간 파장)이다. 제안된 공진 슬롯은 소형이고, 작은 공진 컨덕턴스 그리고 짧으면서도 안정된 공진 길이 등의 장점을 가진다. 부가적으로 슬롯을 도파관 슬롯 배열에 적용할 때 각 슬롯의 특성들이 인접한 슬롯에 의해서 영향을 적게 받는다. 부엽 준위 -20 dB를 가지는 <TEX>$4{\times}1$</TEX> 도파관 슬롯 배열 안테나를 설계, 제작한 후 실험하였다. 측정결과들이 시뮬레이션 결과들과 잘 일치하고, 주파수 9.41 GHz에서 부엽 준위 -15.9 dB, E-평면 반치각 <TEX>$110.2^{\circ}$</TEX>, H-평면 반치각 <TEX>$21.2^{\circ}$</TEX>이다. In this paper, a small round-ended slot loaded by double ridges on the broad wall of a rectangular waveguide is presented as an element for a waveguide slot-array antenna(WSAA). By properly adjusting the ridge dimension, a resonance of the slot at a desired frequency can be achieved. The resonant length of the proposed slot is about <TEX>$0.26{\lambda}_0$</TEX>(free space wave length) at the resonance frequency. The proposed resonant slot has some advantageous properties, such as small size, small resonant conductance, and short and stable resonant slot length. In addition, the characteristics of the slots are slightly affected by the adjacent elements when the slots are arrayed for a waveguide slot antenna. A <TEX>$4{\times}1$</TEX> WSAA with -20 dB side-lobe level(SLL) is designed, fabricated, and tested experimentally. The measured results are well agreed with the simulated ones and have an SLL of -15.9 dB and a half-power beam width of <TEX>$110.2^{\circ}$</TEX> in the E-plane and <TEX>$21.2^{\circ}$</TEX> in the H-plane, respectively, at 9.41 GHz.

Alveolar ridge resorption after tooth extraction: A consequence of a fundamental principle of bone physiology

It is well established that tooth extraction is followed by a reduction of the buccolingual as well as the apicocoronal dimension of the alveolar ridge. Different measures have been taken to avoid this bone modelling process, such as immediate implant placement and bone grafting, but in most cases with disappointing results. One fundamental principle of bone physiology is the adaptation of bone mass and bone structure to the levels and frequencies of strain. In the present article, it is shown that the reduction of the alveolar ridge dimensions after tooth extraction is a natural consequence of this physiological principle.

Biphasic alloplastic graft used to preserve the dimension of the edentulous ridge: an experimental study in the dog

Loss of teeth results in marked qualitative and quantitative alterations of the alveolar process at the edentulous site. It was observed that a graft comprised of bovine bone mineral placed in the fresh extraction socket delayed tissue modeling, but preserved the dimension of the ridge at edentulous sites. To analyze the influence of a biphasic synthetic graft on tissue modeling and remodeling during healing of extraction wounds. Five beagle dogs were used. Two premolars in the maxilla and two in the mandible were included. Full thickness flaps were elevated and the distal roots were removed. An alloplastic graft (BPCAP; α-TCP core coated with nanocrystalline biomimetic hydroxyapatite) embedded in porcine collagen was placed to fill the fresh extraction socket of the premolar sites. Flaps were replaced to cover the entrance of the extraction sockets during early healing. The extraction and grafting procedures were scheduled to allow for the study of 1, 2, and 3 months socket healing. The biopsies from the maxillary sites were decalcified, embedded in paraffin, and stained to allow the study of various aspects of hard tissue formation. The biopsies from the mandibular sites were processed for ground sectioning and used to evaluate alterations of ridge dimensions after 3 months of socket healing. It was documented that the biphasic alloplastic graft did not undergo marked resorption during tissue modeling and remodeling, but allowed large amounts of bone to form within the post-extraction site. Grafting the experimental sites with this biomaterial furthermore counteracted ridge resorption that otherwise occurs following tooth extraction.

A Clinical and Histomorphometric Study of Calcium Sulfate Compared With Freeze‐Dried Bone Allograft for Alveolar Ridge Preservation

Many materials have been found to be effective in ridge preservation. The purpose of this study is to determine whether calcium sulfate (CS) is as effective as freeze-dried bone allograft (FDBA) in preserving postextraction ridge dimensions and to evaluate the amount of new bone formation and graft clearance through histologic analysis. Thirty-one extraction sites were selected. Postextraction clinical measurements were made, and sites were divided randomly into the test group (CS) or the control group (FDBA). After graft placement, all individuals received the same postoperative treatment and instructions. Participants were recalled after 3 months, measurements were made, and sites were re-entered. Bone samples were harvested and analyzed with histologic methodology for new bone formation and remaining residual graft. Thirteen test and 15 control sites were evaluated. There was no significant change in vertical ridge height before or after surgery within the test and control groups (P = 0.57, P = 0.68, respectively). There was a significant decrease in bucco-lingual ridge width for both groups (P = 0.0003, P = 0.0075, respectively), but the difference between groups was not significant (P = 0.11). Histologic analysis revealed an average of 32% new bone formation with 2.5% graft remaining for the test group and 16.7% new bone formation with 21% graft remaining for the control. Results indicate that CS is as effective as FDBA in preserving postextraction ridge dimensions in non-molar extraction sites. There is greater clearance of CS with more new bone formation after ≈3 months compared with FDBA in these sites. This paper received the Maynard K. Hine Award for Excellence in Dental Research presented by the Indiana Section of the American Association for Dental Research and supported by Procter & Gamble.

Effect of exposure time on the accuracy and reliability of cone beam computed tomography in the assessment of dental implant site dimensions in dry skulls

To investigate the accuracy and reliability of implant site measurements, recorded from low-dose cone beam computed tomography (CBCT) images. CBCT reformatted images of five skulls were obtained using 40, 20 and 7s exposure protocols. From these protocols, edentulous ridge dimensions were recorded by two observers and compared with measurements recorded directly from the bone. The measurement errors and intra- and inter-examiner reliability were calculated for each exposure protocol and compared with each other. The mean absolute errors from the 40, 20 and 7s protocols were 0.50, 0.46, and 0.51mm, respectively. The intra-examiner reliability scores were 0.996, 0.995 and 0.998, respectively. The inter-examiner reliability scores were 0.993, 0.998 and 0.994, respectively. There was no significant difference in accuracy or reliability between the three protocols. In imaging of dry skulls, lowering the CBCT exposure time from 40s to 20 or 7s does not affect the reliability or accuracy of implant site measurements.

Bone Healing after Tooth Extraction with or without an Intervention: A Systematic Review of Randomized Controlled Trials

To assess whether the use of a graft and/or membrane post-tooth extraction improves healing of the site dimensionally, radiographically, and/or histologically. MEDLINE and EMBASE and the Cochrane Central register of controlled trials (CENTRAL) were searched up until August 2011. Randomized controlled trials that included and compared healing post-tooth extraction between a control (no intervention) and a graft and/or membrane (test) were selected. Titles and abstracts of 2,861 papers were screened. A total of 42 papers were selected for full text reading. Nine papers met the eligibility criteria and were selected for further analysis. Because of the varying graft materials used and the different methods of investigation, as well as the variation in follow-up times, a meta-analysis was not possible. The present review found that clinically, there was a range in loss of width in the control sites of 2.46 mm (SD 0.4 mm) to 4.56 mm (SD 0.33 mm) compared to 1.14 mm (SD 0.87 mm) to 2.5 mm (SD 1.2 mm) in the test sites. The range in loss of height in control sites was 0.9 mm (SD 1.6 mm) to 3.6 mm (SD 1.5 mm) compared to a gain of 1.3 mm (SD 2 mm) to a loss of 0.62 mm (SD 0.51 mm) in test sites. Radiographically a range of change in bone height of between 0.51 mm (No SD) to 1.17 mm (SD 1.23 mm) was noted in control sites compared to a change of between 0.02 mm (SD 1.2 mm) and 1 mm (SD 1.4 mm) in test sites. There is limited data regarding the effectiveness of alveolar ridge preservation therapies when compared to the control. Overall the socket intervention therapies did reduce alveolar ridge dimensional changes post-extraction, but were unable to prevent resorption. Histology did demonstrate a large proportion of residual graft material that may account for some of the difference in alveolar ridge dimensions at follow up.

Histologic Comparison of Healing After Tooth Extraction With Ridge Preservation Using Mineralized Versus Demineralized Freeze‐Dried Bone Allograft

Allografts, such as demineralized freeze-dried bone allograft (DFDBA) and mineralized freeze-dried bone allograft (FDBA) are commonly used by clinicians for ridge preservation procedures. The primary objective of this study is to histologically evaluate and compare the healing of non-molar extraction sockets grafted with DFDBA versus FDBA for ridge preservation. The secondary aim of this study is to compare dimensional changes in ridge height and width after grafting with these two materials. Forty patients were randomly divided into two groups of 20. Extraction sockets were filled with either FDBA or DFDBA. To minimize variables associated with the organ donor and with tissue processing, all of the graft material was procured from a single donor; the only difference in the two materials was the percentage mineralization of the final bone graft. A 2-mm-diameter core biopsy was taken from each grafted site ≈19 weeks after grafting. Histomorphometric analysis was performed to determine percentage of vital bone, residual graft particles, and connective tissue (CT)/other non-bone components. There were no significant differences when comparing changes in alveolar ridge dimensions of the two groups. There was no significant difference in percentage CT/other between groups. DFDBA had a significantly greater percentage of vital bone at 38.42% versus FDBA at 24.63%. The DFDBA group also had a significantly lower mean percentage of residual graft particles at 8.88% compared to FDBA at 25.42%. This study provides the first histologic and clinical evidence directly comparing ridge preservation with DFDBA versus FDBA in humans and demonstrates significantly greater new bone formation with DFDBA.

Histologic Comparison of Healing After Ridge Preservation Using Human Demineralized Bone Matrix Putty With One Versus Two Different‐Sized Bone Particles

Ridge preservation can minimize the loss of alveolar bone subsequent to tooth extraction in preparation for implant therapy. The purpose of this study is to histologically and clinically compare human demineralized bone matrix (DBM) putty with one size of bone particles (SPS) to human DBM putty with two different sizes of bone particles (multiple particle sizes [MPS]) in ridge preservation after molar extractions. Molar tooth extraction and ridge preservation were performed in 20 participants for each treatment group. Approximately 20 weeks after grafting, core biopsies were obtained during implant placement and analyzed under light microscopy. Specimens were analyzed for the percentage area of vital bone, residual graft particles, and non-mineralized structures (connective tissue/other non-mineralized tissue [CT]). Changes in alveolar ridge dimensions were also determined. Sixteen participants in the SPS group and 14 in the MPS group completed the study. The SPS group had a mean of 49% vital bone, 8% residual graft, and 43% CT. The MPS group had 53%, 5%, and 42%, respectively. Patients in both groups lost a mean of <1 mm alveolar height on the buccal and lingual aspects and <1.5 mm of total ridge width. There were no statistically significant differences between the two groups for any clinical or histologic parameters. The results of this study suggest that addition of larger bone particles to DBM putty does not offer additional benefit in the preservation of alveolar bone after the extraction of molar teeth.

Analysis of quadruple corner-cut ridged square waveguide using a scaled boundary finite element method

This paper describes the development of an efficient semi-analytical method, namely scaled boundary finite-element method (SBFEM) for a quadruple corner-cut ridged square waveguide. Thinking about its symmetry, only a quarter of its cross-section needs to be considered and divided into a few sub-domains. Only the boundaries of the sub-domains are discretized with line elements leading to great flexibility in mesh generation. The singularities in the re-entrant corners are represented analytically by locating the scaling center in those points. Variational principle approach is presented to formulate the basis SBFE equations for the sub-domains. Then, an equation of the ‘stiffness matrix’ on the discretized boundary is established. Finally, by using the continued-fraction solution and introducing auxiliary variables, a generalized eigenvalue equation with respect to the cutoff wave number is obtained without introducing an internal mesh. Numerical results are presented to verify the accuracy and efficiency of the present technique. Variations of the cutoff wave numbers of the dominant and higher-order modes for both TE and TM cases with the corner-cut ridge dimensions are investigated in details. Simple approximate equations are found to accurately predict the cutoff wave number of TE20U, TE22, TM11 and TM13L modes. The single mode bandwidth of the waveguide is also calculated.

Porcine‐Derived Xenograft Combined with a Soft Cortical Membrane versus Extraction Alone for Implant Site Development: A Clinical Study in Humans

An adequate alveolar crest is essential for implant placement in terms of esthetics and function. The objective of this randomized clinical trial was to compare the preservation of the alveolar ridge dimensions following tooth extraction using porcine-derived xenograft combined with a membrane versus extraction-alone (EXT) sites. Fifteen patients who required double extraction of contralateral premolars and delayed implant placement were randomly selected to receive both ridge-preservation procedure and EXT. The test sites (alveolar ridge preservation [ARP]) included 15 sockets treated using a corticocancellous porcine bone xenograft (OsteoBiol® Gen-Os; Tecnoss srl, Giaveno, Italy) associated with a soft cortical membrane (OsteoBiol® Lamina; Tecnoss srl), while the corresponding control sites (EXT) were left without grafting for EXT. Horizontal and vertical ridge dimensions were recorded at baseline and 6 months after extractions. After 6 months, the EXT sites showed a significantly greater reabsorption of the buccolingual/palatal dimension of the alveolar ridge (3.7 ± 1.2 mm) compared with the ARP sites (1.8 ± 1.3 mm). The mean vertical ridge height reduction in the control sockets was 3.1 ± 1.3 mm at the buccal sites and 2.4 ± 1.6 mm at the lingual sites compared with 0.6 ± 1.4 and 0.5 ± 1.3 mm, respectively, in the test sockets. The differences between test and control sockets were not significant for the mesial and distal measurements. The placement of a porcine xenograft with a membrane in an extraction socket can be used to reduce the hard tissue reabsorption after tooth extraction compared with EXT.

Fate of autologous and fresh‐frozen allogeneic block bone grafts used for ridge augmentation. A CBCT‐based analysis

To evaluate dimensional changes in autologous (AT) and fresh-frozen allogeneic (AL) block bone grafts 6months after alveolar ridge augmentation. Twenty-six partially or totally edentulous patients treated either with fresh-frozen AL bone or AT bone onlay block grafts prior to implant placement (13 patients in each group), were included in this analysis. Patients received CBCT (i-CAT Classic) examinations prior to surgery and 14days and 6months after grafting. Differences in alveolar ridge area among the various observation times were evaluated by planimetric measurements on two-dimensional CBCT images of the grafted regions. Nineteen grafted blocks from each group were evaluated. Significant increase in alveolar ridge dimensions, allowing implant placement, was obtained with both types of grafts 6months after grafting; no significant differences in alveolar ridge area were observed between the groups at the various observation times. However, graft resorption in the AL group was significantly larger compared to that in the AT group at 6months. Larger bone graft resorption was seen in patients treated with fresh-frozen AL bone than in those treated with AT bone 6months following alveolar ridge augmentation.

Predictive value of ridge dimensions on autologous bone graft resorption in staged maxillary sinus augmentation surgery using Cone‐Beam CT

No studies are available that provide predictive parameters regarding the expected amount of resorption after maxillary sinus augmentation surgery using autologous bone grafts. Therefore, the aim of this study was to determine parameters influencing the outcome of the bone graft resorption process. In 20 patients, three-dimensional analysis of alveolar ridge dimensions and bone graft volume change in the atrophic posterior maxilla was performed by Cone-Beam Computerized Tomography imaging. Ridge dimensions were assessed before maxillary sinus augmentation surgery. Bone graft volumes were compared after maxillary sinus floor augmentation surgery and a graft healing interval of several months. To analyze the relation between bone volume changes with the independent variables, patients' gender, age, alveolar crest height and width, and graft healing time interval, a multi-level extension of linear regression was applied. A residual bone height of 6.0mm (SD=3.6mm) and 6.2mm (SD=3.6mm) was found at the left and right sides, respectively. Moreover, alveolar bone widths of 6.5mm (SD=2.2mm) and 7.0mm (SD=2.3mm) at the premolars, and 8.8mm (SD=2.2mm) and 8.9mm (SD=2.5mm) at the molars regions were found at the left and right site, respectively. Bone graft volume decreased by 25.0% (SD=21.0%) after 4.7months (SD=2.7, median=4.0months) of healing time. The variables "age" (P=0.009) and mean alveolar crest "bone height" (P=0.043), showed a significant influence on bone graft resorption. A decrease of 1.0% (SE=0.3%) of bone graft resorption was found for each year the patient grew older, and an increase in bone graft resorption of 1.8% (SE=0.8%) was found for each mm of original bone height before sinus floor augmentation. Graft resorption occurs when using autologous bone grafts for maxillary sinus augmentation. Alveolar crest bone height and patient age have a significant effect on graft resorption, with increased resorption for higher alveolar crest bone height and decreased resorption for older patients. Consequently, patient characteristics that affect the process of bone graft resorption should be given full consideration, when performing sinus augmentation surgery.

Analysis of quadruple corner‐cut ridged elliptical waveguide by scaled boundary finite element method

SUMMARYThe scaled boundary FEM (SBFEM) is a novel semi‐analytical approach, which combines the advantages of the FEM and BEM with appealing features of its own. In this paper, the method is applied to analyse the quadruple corner‐cut ridged elliptical waveguide. A quarter of the waveguide is adopted and divided into a few subdomains. SBFEM only discretizes the surface boundaries of the subdomains in the sense of FEM, and no discretization of side‐face boundaries is needed, leading to great flexibility in mesh generation with very few nodes. It transforms the governing PDEs to ODEs of the radial parameter by the variational principle. The radial differential equation is then solved fully analytically without adoption of any numerical scheme, which brings out the inherent advantage for solving a singularity problem. Based on the SBFEM governing equation and introducing the dynamic stiffness of waveguide, a generalised eigenvalue equation with respect to cut‐off wave number is formulated by a continued fraction solution without introducing an internal mesh. The numerical example demonstrates the simplicity, excellent computation accuracy and efficiency of the present SBFEM approach. Influences of corner‐cut ridge dimensions on the cut‐off wave numbers of modes are examined in detail. Therefore, these results provide an extension to the existing design data for ridged waveguides and are considered helpful in practical applications. Copyright © 2011 John Wiley &amp; Sons, Ltd.

A comparative study of the accuracy and reliability of multidetector CT and cone beam CT in the assessment of dental implant site dimensions: Author response

A comparative study of the accuracy and reliability of multidetector CT and cone beam CT in the assessment of dental implant site dimensions: Author response

A comparative study of the accuracy and reliability of multidetector CT and cone beam CT in the assessment of dental implant site dimensions

Free AccessLetter to the editorA comparative study of the accuracy and reliability of multidetector CT and cone beam CT in the assessment of dental implant site dimensionsK Kamburoğlu and S YükselK KamburoğluSearch for more papers by this author and S YükselSearch for more papers by this authorPublished Online:28 Jan 2014https://doi.org/10.1259/dmfr/30789406SectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail AboutWe read the article written by AA Al-Ekrish and M Ekram, “A comparative study of the accuracy and reliability of multidetector CT and cone beam CT in the assessment of dental implant site dimensions”,1 with great interest.We would like to congratulate the authors for their effort in the preparation of the manuscript. According to the mentioned study, measurements recorded for both modalities showed high intra and interexaminer reliability. Although cone beam CT (CBCT) measurements were significantly more accurate than those of multi-detector CT (MDCT), both systems showed clinically and statistically significant errors.In this research, the measurements were recorded by two observers. As stated by the authors, CBCT measurements are highly operator dependent and this may explain the lower interexaminer reliability calculated for CBCT compared with MDCT. Interestingly, no specific information was given concerning the specialty and experience of the observers with tomographic slices. When presenting the results (Tables 1–3), which observer was taken into account? Did the authors calculate any intra and interobserver agreement? It is our belief that these agreement calculations should be done and then the results could be presented by evaluating these agreements.The authors had presented the intra and interobserver reliability using correlation and Cronbach's alpha. However, while assessing agreement between two measurement techniques, it is not appropriate to use the correlation analysis. For those types of studies, Bland-Altman2 is a better method of choice. Also, for the evaluation of reliability, Cronbach's alpha is not an appropriate coefficient; Cronbach's alpha is used to rate the internal consistency or the correlation of the items in a test and it is generally used to evaluate the scales. It is appropriate to use intraclass correlation coefficient (ICC) instead of Cronbach's alpha. ICC is used to measure inter-rater reliability for two or more raters.Another drawback of the study design is the wrongly chosen voxel resolution for the Iluma CBCT scanner (Imtek Imaging, 3M Company, St Paul, MN) which was set at 0.3 mm. A similar research article published 2 years earlier, conducted by the authors of the present “letter to the editor”, used the same CBCT unit.3 We found that the accuracy of measurements of various distances surrounding the mandibular canal was highly comparable with that of digital caliper measurements. Our results were obtained from Iluma CBCT scanner images reconstructed at 0.2 mm voxel and two trained oral radiologists served as observers. It would be interesting to know the effects of different voxels in the implant site measurement accuracy.The authors also mentioned in the last paragraph of their discussion that “recording of the ridge dimensions for implant site assessment and placement of implants should be performed by the same operator”. We do not have objection to this idea as long as an oral and maxillofacial radiologist consultation is provided.We believe that the way the authors present their statistical analysis, the sole selection of a 0.3 mm voxel size and the obscure observer performance may mislead the readership with regard to the accuracy of assessment of dental implant site dimensions with CBCT.We hope the authors will consider our constructive comments in their future work.References1 Al-Ekrish AA , Ekram M . A comparative study of the accuracy and reliability of multidetector computed tomography and cone beam computed tomography in the assessment of dental implant site dimensions. Dentomaxillofac Radiol 2011;40:67–75. Link ISI, Google Scholar2 Bland JM , Altman DG . Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307–310. Crossref Medline ISI, Google Scholar3 Kamburoğlu K , Kılıç C , Özen T , Yüksel SP . Measurements of mandibular canal region obtained by cone-beam computed tomography: a cadaveric study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107:e34–e42. Crossref Medline, Google Scholar Previous article Next article FiguresReferencesRelatedDetailsCited byComparison of in situ cone beam computed tomography scan data with ex vivo optical scan data in the measurement of root surface areaOral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, Vol. 128, No. 5 Volume 40, Issue 7October 2011Pages: 403-470 2011 The British Institute of Radiology History Published onlineJanuary 28,2014 Metrics Download PDF

Wound healing of extraction sockets

The extraction of a tooth initiates a series of reparative processes involving both hard tissue (i.e. alveolar bone) and soft tissues (periodontal ligament, gingiva). The biological events occurring during the healing of an extraction socket and their chronological sequence have been evaluated in different animal and human studies. In the present review, the healing process of a tooth extraction wound was described. Factors affecting the histological aspects of the healing phase as well as the post extraction alterations of the ridge dimensions were also considered. Additionally, the healing of an extraction socket where a dental implant has been placed immediately after tooth removal was described in details. Finally, the histological and clinical outcomes of the application of different reconstructive technologies to the post‐extraction socket was evaluated.