A comparison of the diagnostic advantages of panoramic radiography and computed tomography scanning for placement of root form dental implants

Mandibular canal assessment in dentate and edentulous ridges of 400 Iraqi Arab and Kurdish populations using cone beam computed tomography

Objectives

This study aims to compare differences in mandibular canal (MC) location between dentate and edentulous ridges, in the second premolar region as well as the first, second, and third molar regions using cone beam computed tomography (CBCT) of Arabic and Kurdish Iraqi populations.

Materials and Methods

CBCT images of 400 subjects (200 Arabs, 200 Kurds) were collected from radiological archives. RadiAnt DICOM software (Medixant, Poland) was used for image analyses. Measurements were performed from MC to buccal and lingual alveolar crests and to buccal, lingual, and inferior aspect of the mandible for both dentate and edentulous ridges. Additionally, distance to the most superior aspect of residual edentulous ridge were performed. Independent t-test and Mann-Whitney U Test were performed utilising SPSS v.26.

Results

Distances from MC to buccal and lingual alveolar crests were consistently lower in edentulous ridge compared to dentate ridge across all teeth regions. Distances to lingual and inferior border of the mandible were higher in edentulous ridge compared to dentate ridge of all teeth regions. Distances to buccal surface of the mandible varies with fluctuations of dentate and edentulous ridges displaying higher measurements. Distance to superior aspect of residual edentulous ridge revealed mean values in the range of 13.45 to 15.69 mm in Arabs and 13.96 to 16.37 mm in Kurds.

Conclusions

Discrepancy in vertical position of MC was observed between dentate and edentulous ridges within Arab and Kurd populations. Horizontal position of MC was unaffected by tooth loss and found to be closer to lingual surface of all molars. The residual alveolar ridge was sufficient to accommodate the common length and width of dental implants.

Clinical significance

The findings could play a crucial role in planning surgical interventions of the mandible, helping to prevent complications that might arise due to inadequate preoperative assessments.

Nasal cavity perforation by implant fixtures: case series with emphasis on panoramic imaging of nasal cavity extending posteriorly

The nasal cavity is an important landmark when considering implant insertion into the anterior region of the maxillary arch. The perforation of implants into the nasal cavity may cause complications, such as implant migration, inflammation, or changes in nasal airflow; thus, precise assessment of the nasal cavity is mandatory.Three cases of nasal cavity perforation by dental implants are presented, including one case of implant fixture migration into the nasal cavity. On panoramic radiographs of the patients, the following common features were observed: the horizontal radiopaque line of the hard palate was observed to be inferior to or similar to that of the antral floor and the bone between the lateral wall of the nasal cavity and the medial wall of the maxillary sinus was emphasized in a triangular shape.When the maxillary sinus is small and alveolar bone resorption is severe, panoramic evaluation may cause overestimation of the available residual bone, particularly in the maxillary canine/premolar region. Therefore, the residual bone should be reevaluated three-dimensionally to measure the exact bony shape and volume.

CBCT for Diagnostics, Treatment Planning and Monitoring of Sinus Floor Elevation Procedures

Sinus floor elevation (SFE) is a standard surgical technique used to compensate for alveolar bone resorption in the posterior maxilla. Such a surgical procedure requires radiographic imaging pre- and postoperatively for diagnosis, treatment planning, and outcome assessment. Cone beam computed tomography (CBCT) has become a well-established imaging modality in the dentomaxillofacial region. The following narrative review is aimed to provide clinicians with an overview of the role of three-dimensional (3D) CBCT imaging for diagnostics, treatment planning, and postoperative monitoring of SFE procedures. CBCT imaging prior to SFE provides surgeons with a more detailed view of the surgical site, allows for the detection of potential pathologies three-dimensionally, and helps to virtually plan the procedure more precisely while reducing patient morbidity. In addition, it serves as a useful follow-up tool for assessing sinus and bone graft changes. Meanwhile, using CBCT imaging has to be standardized and justified based on the recognized diagnostic imaging guidelines, taking into account both the technical and clinical considerations. Future studies are recommended to incorporate artificial intelligence-based solutions for automating and standardizing the diagnostic and decision-making process in the context of SFE procedures to further improve the standards of patient care.

Guided Endodontics as a Personalized Tool for Complicated Clinical Cases

The aim of this paper is to present a technique to individualize root canal localization in teeth with calcified root canals using a digitally planned, 3D-printed endodontic guide. Root canal calcification is characterized by the apposition of tertiary dentin along the canal wall. The endodontic treatment of teeth with calcified canals is often challenging. However, digital dentistry meets these challenges. Merging CBCT images with an intraoral scan allows a clinician to prepare an endodontic guide. This article describes the clinical and digital workflow of the guided endodontic access approach in teeth with difficulties in terms of root canal localization due to post-traumatic pulp canal obliteration (PCO) and canal calcification in elderly patients. The path of entry into the root canal system was planned using cone-beam computed tomography (CBCT). The template was printed on a 3D printer using transparent resin. During root canal treatment (RCT), the endodontic tool was inserted through the sleeve until the desired location was reached. The use of an endodontic guide allowed for minimally invasive RCT, avoiding the excessive loss of tooth structures. Navigated endodontics enables clinicians to perform RCT in a more predictable manner and allows clinicians to avoid iatrogenic complications, which improves the treatment prognosis.

Free-Hand versus Surgical Guide Implant Placement

One of the most key areas of dentistry is dental implant surgery. The use of digital equipment and software in dentistry has developed considerably in recent years compared to other fields of medicine. Since examining the advantages and disadvantages of each approach, along with case studies, can help physicians make informed decisions, this review study aims to raise the awareness of dentists to make easier decisions about using guided or free-hand surgery. When planning for a dental implant, one of the most challenging questions that doctors face is which method to use (guided surgery or free-hand). Choosing the right method, such as other clinical considerations, will depend on the individual circumstances of each patient and the preference of the treating physician. Free-hand surgery is a cost-effective method in which the flap is reflected, and, according to the doctor's diagnostic information, an implant is placed, which in many cases is a useful method. Guided surgery has the highest level of accuracy and control, in which osteotomy is designed and printed through a digital surgery guide, and depending on the complexity of the case and the patient's anatomy, it has a higher level of value than free surgery. The surgical guide helps the surgeon make the implant surgery more accurate, safer, simpler, at a lower cost, and in less time. In fact, there are patterns that convey information about the position of the tooth to the dentist before the implant is placed.

Atenafu E, Ketabi M. CBCT data relevant in treatment planning for immediate maxillary molar implant placement

Background. This study used CBCT images to evaluate the suitability of maxillary first and second molar sites to receive immediate implants. Buccopalatal and mesiodistal widths of maxillary molar inter-radicular septum were evaluated at three different levels (crestal, middle, and apical), in addition to assessments of the root apex and furcation proximities to the sinus floor and comparisons of these measurements between the first and second upper molar sites before extraction.Methods. A total of 427 dental sites from 223 patients were used to measure the buccopalatal and mesiodistal widths of inter-septal/furcal (IRS) bone of maxillary first and second molars and vertical distances from the furcation and from all the root apices to the sinus floor (SF).Results. Mean coronal-most buccopalatal/mesiodistal IRS widths were 7.33/6.52 mm for the first and 6.86/5.85 mm for the second molars (P=0.008). Corresponding mean FSD (furcation-sinus floor) values were 9.69 mm (range: 2.02-24.68 mm) and 8.84 mm (range: 1.48-25.09 mm). Mean distances from all the root apices to SF were <3 mm. The palatal roots of the first molars had higher sinus intrusion rates (28.85%) than their buccal counterparts, while for the second molars, the mesiobuccal roots showed the highest sinus intrusion (37.65%).Conclusion. In the current patient sample, 61.7% of the first and 34% of the second molars had a sufficiently broad IRS to encase a 5-mm-diameter IMI (immediate molar implant) completely. The mean FSD of 9 mm for both molars indicated that some sinus floor elevation would likely be needed unless short implants were used.

Comparison of the performances of low-crystalline carbonate apatite and Bio-Oss in sinus augmentation using three-dimensional image analysis

BACKGROUND

In locations where the alveolar bone height is low, such as at the maxillary molars, implant placement can be difficult, or even impossible, without procedures aimed at generating new bone, such as sinus lifts. Various types of bone graft materials are used after a sinus lift. In our study, a three-dimensional image analysis using a volume analyzer was performed to measure and compare the volume of demineralized bovine bone mineral (Bio-Oss®) and carbonate apatite (Cytrans®) after a sinus lift, as well as the amount of bone graft material resorption. Patient data were collected from cone-beam computed tomography images taken before, immediately following, and 6 months after the sinus lift. Using these images, both the volume and amount of resorption of each bone graft material were measured using a three-dimensional image analysis system.

RESULTS

The amount of bone resorption in the Bio-Oss®-treated group was 25.2%, whereas that of the Cytrans®-treated group was 14.2%. A significant difference was found between the two groups (P < 0.001).

CONCLUSIONS

Our findings indicate that the volume of bone resorption was smaller in the Cytrans®-treated group than in the Bio-Oss®-treated group, suggesting that Cytrans® is more promising for successful implant treatments requiring a sinus lift.

Efecto de los daños causados por el insecto escudo verde (Palomena prasina L.) en las características cualitativas de la avellana

Este estudio se realizó en 2018 para determinar el efecto del daño del insecto escudo verde (DV) en las propiedades químicas del cultivar de avellana "Tombul". La composición proximal, proteína, lípidos totales (LT), carbohidratos, relación total de cenizas (CT), vitamina E (VE), fenólicos totales, valores de energía (E), color, composición de ácidos grasos, ácidos grasos totales, oxidación de lípidos e índice de calidad nutricional se determinaron en relación con los daños causados por el insecto. Se encontró que el nivel de LT, CT, VE, E, ácidos grasos monoinsaturados (MUFA) y ácidos grasos insaturados/saturados (UFA/SFA) fue menor en los granos de DV que en los granos buenos (GB). Aunque los granos de DV tienen niveles más altos de yodo, acidez, grasa libre y peróxidos, tienen niveles más bajos de la relación ácido oleico/linoleico y de los valores de rancimat. Además, los granos de DV tienen una relación más baja PUFA/SFA y de hipocolesterolémica/hipercolesterolémica, pero tienen valores de índice de aterogenicidad y trombogenicidad más altos.

Comparison of panoramic radiography and cone-beam computed tomography for assessing radiographic signs indicating root protrusion into the maxillary sinus

Purpose

This study investigated correlations between findings on panoramic radiographs and cone-beam computed tomography (CBCT) to assess the relationship between the maxillary sinus floor and the roots of maxillary posterior teeth. In addition, radiographic signs indicating actual root protrusion into the maxillary sinus were evaluated on panoramic radiographs.

Materials and Methods

Paired panoramic radiographs and CBCT images from 305 subjects were analyzed. This analysis classified 2,440 maxillary premolars and molars according to their relationship with the maxillary sinus floor on panoramic radiographs and CBCT images. In addition, interruption of the sinus floor was examined on panoramic radiographs.

Results

Root protrusion into the maxillary sinus occurred most frequently in the mesiobuccal roots of the second molars. The classification according to panoramic radiographs and CBCT images was the same in more than 90% of cases when there was no contact between the root apex and the sinus floor. When the panoramic radiograph showed root protrusion into the sinus, the CBCT images showed the same classification in 67.5% of second molars, 48.8% of first molars, and 53.3% of second premolars. There was a statistically significant relationship between interruption of the sinus floor on panoramic radiographs and root protrusion into the sinus on CBCT images.

Conclusion

The presence of root protrusion into the sinus on panoramic radiographs demonstrated a moderate ability to predict root protrusion into the maxillary sinus. Interruption of the maxillary sinus floor could be considered an indicator of actual root protrusion into the maxillary sinus.

Factors affecting maxillary sinus pneumatization following posterior maxillary tooth extraction

Purpose

The aims of the present study were 1) to quantitatively evaluate the extent of sinus pneumatization and 2) to determine the factors affecting sinus pneumatization.

Methods

Based on implant treatment records, a list of patients who underwent implant placement on the posterior maxilla was obtained. Among them, patients with pre-extraction and post-extraction (before implant placement) panoramic radiographs were selected. After excluding radiographs with low resolution and image distortion, the radiographs before and after extraction were superimposed using computer software. Subsequently, the extent of sinus pneumatization (the vertical change of the sinus floor) was measured. Simple and multiple mixed models were used to determine the factors affecting sinus pneumatization.

Results

A total of 145 patients were eligible for the present investigation. The average extent of sinus pneumatization was 1.56±3.93 mm at 176 tooth sites. Male sex, single tooth extraction, extraction of an endodontically compromised tooth, a class I root-sinus relationship, and sinus membrane thickening >10 mm favored pneumatization, but without statistical significance. The maxillary second molar presented the greatest pneumatization (2.25±4.39 mm) compared with other tooth types. This finding was confirmed in the multiple mixed model, which demonstrated a statistically significant impact of the extraction of a second molar compared with the extraction of a first premolar.

Conclusions

Maxillary sinus pneumatization was 1.56±3.93 mm on average. The extraction of a second molar led to the greatest extent of pneumatization, which should be considered in the treatment plan for this tooth site.

A Simple and Safe Approach for Maxillary Sinus Augmentation with the Advanced Surgical Guide

Objective: The development of digital dentistry has contributed to the astonishing advancement of implant dentistry. Furthermore, digital technology is expected to be applied extensively to sinus augmentation, which is an advanced technique for implant surgery. This study introduces a simple method for a safer and more precise lateral window opening for sinus augmentation using a navigation program. Methods: Five eligible patients with residual alveolar bone of 4 mm or less are presented, requiring lateral approach for sinus augmentation. Navigation system was opted for the sinus lift with simultaneous implant placement. Virtual planning started with establishing the adequate position of the lateral window based on the radiographic images and the scanned file of the dentition. The position of the window was indicated on the guide within the program. Afterwards, the virtually designed surgical guide was fabricated either with 3D printer or milling machine for the actual surgery. Results: All the patients who underwent surgery with the surgical guide showed no sign of clinical complications including pain, swelling, nausea, epistaxis, or early loss of the implants. Results of radiographic evaluation also showed adequate placement of the implants in a pre-planned position, and the sinus window was also formed in the desired location. Conclusion: Lateral window opening combined with digital navigation system is believed to be a promising technique for a more precise as well as safer sinus augmentation.

Guided implant surgery risks and their prevention

Ideal implant placement may reduce surgical complications, such as nerve injury and lingual cortical plate perforation, and minimize the likelihood of functional and prosthetic compromises. Guided implant surgery (GIS) has been used as the means to achieve ideal implant placement. GIS refers to the process of digital planning, custom-guide fabrication, and implant placement using the custom guide and an implant system-specific guided surgery kit. GIS includes numerous additional steps beyond the initial prosthetic diagnosis, treatment planning, and fabrication of surgical guide. Substantial errors can occur at each of these individual steps and can accumulate, significantly impacting the final accuracy of the process with potentially disastrous deviations from proper implant placement. Pertinent overall strategies to reduce or eliminate these risks can be summarized as follows: complete understanding of the possible risks is fundamental; knowledge of the systems and tools used is essential; consistent verification of both diagnostic and surgical procedures after each step is crucial; proper training and surgical experience are critical. This review article summarizes information on the accuracy and efficacy of GIS, provides insight on the potential risks and problems associated with each procedural step, and offers clinically relevant recommendations to minimize or eliminate these risks.

Accuracy of Computer-Guided Template-Based Implant Surgery: A Computed Tomography-Based Clinical Follow-Up Study

OBJECTIVE

The aim of this clinical study was to analyze the accuracy of computer-guided implant surgery.

MATERIALS AND METHODS

Assisted by computed tomography (CT)-based planning software and navigational templates, 16 patients successfully received 26 dental implants. Each implant parameter (a-d) was calculated based on superimposed preoperative and postoperative cone beam CT scans: (a) deviation at entry point; (b) deviation at apex; (c) angular deviation; and (d) depth deviation.

RESULTS

Mean central deviation at implant entry point and apex was 0.91 mm (standard error [SE] = 0.11 mm; 95% confidence interval [CI]: 0.69-1.13) and 1.22 mm (SE = 0.11 mm; 95% CI: 0.99-1.45), respectively. Mean angulation deviation was 4.11 degrees (SE = 0.52 degrees; 95% CI: 3.04-5.17) and the average depth deviation was 0.65 mm (SE = 0.11 mm; 95% CI: 0.42-0.87). For the total number of implants placed, the maximum error was 2.34 mm at entry point, 2.71 mm at apex, 9.44 degrees in angular deviation, and 2.00 mm in depth deviation.

CONCLUSION

Great accuracy was reached even in advanced cases with prior bone augmentation and complex traumas. This leads to the conclusion that particularly in advanced cases, computer-guided implantation can be beneficial.

Accuracy of computer-guided surgery for dental implant placement in fully edentulous patients: A systematic review

Assess clinical studies regarding accuracy between virtual planning of computer-guided surgery and actual outcomes of dental implant placements in total edentulous alveolar ridges. A PubMed search was performed to identify only clinical studies published between 2011 and 2016, searching the following combinations of keywords: "Accuracy AND Computer-Assisted Surgery AND Dental Implants." Study designs were identified using the terms: Case Reports, Clinical study, Randomized Controlled Trial, Systematic Reviews, Meta-Analysis, humans. Level of agreement between the authors in the study selection process was substantial (k = 0.767), and the study eligibility was considered excellent (k = 0.863). Seven articles were included in this review. They describe the use of bone and muco-supported guides, demonstrating angular deviations cervically and apically ranging from (minimum and maximum means), respectively, 1.85-8.4 (°), 0.17-2.17 (mm), and 0.77-2.86 (mm). Angular deviations obtained most inaccuracy in maxila. For cervical and apical deviations, accuracy was preponderantly lower in maxilla. Despite the similar deviations measurement approaches described, clinical relevance of this study may be useful to warn the surgeon that safety margins in clinical situations.

Real Versus Virtual Position of Single Implants Installed in Premaxilla via Guided Surgery: A Proof of Concept Analyzing Positional Deviations

The aim of this research letter was to report the results of a pilot study designed to compare the real and virtual position of implants placed using computer-guided flapless implant surgery for single restorations in the premaxilla. A total of 8 patients (2 men and 6 women) with a mean age of 40 years old (range: 32-73 years) had a total of 11 implants inserted using a tooth-supported stereolithographic guide. After implant placement, the positions (coronal, central, and apical) and angulation of the implants installed in relation to those planned were determined via the superposition of pre- and postoperative 3-dimensional models using Dental Slice software (Bioparts, Brasília, Brazil). The mean angular deviation was 2.54° ± 0.71°. The deviations found for the coronal, central, and apical positions were 1.3 ± 0.77 mm, 1.49 ± 0.58 mm, and 2.13 ± 1.32 mm, respectively.

Dental implant navigation system guide the surgery future

No study has investigated the effect of learning curves on the accuracy of dental implant navigation systems. This study evaluated the accuracy of the dental implant navigation system and established the learning curve according to operation site and operating time. Each dental model was used for drilling 3 missing tooth positions, and a patient tracking module was created. The same dentist performed the drilling test for 5 sets of dental models. CT back scanning was performed on the dental models. Customized implants based on the drilled holes were inserted. The relative error between the preoperative planning and actual implant was calculated. Using the dental navigation system could help dentists position implants more accurately. Increasing the frequency with which a dentist used the navigation system resulted in shorter operations. Longitudinal and angular deviation were significantly (P < 0.0001 and P = 0.0164). We found that the same level of accuracy could be obtained for the maxilla and mandible implants. The Student's t test demonstrated that the longitudinal error, but not the total or angular error, differed significantly (P = 0.0012). The learning curve for the dental implant navigation system exhibited a learning plateau after 5 tests. The current system exhibited similar accuracy for both maxillary and mandibular dental implants in different dental locations. The one-way ANOVA revealed that the total, longitudinal, and angular errors differed significantly (P < 0.0001, P < 0.0001 and P = 0.0153). In addition, it possesses high potential for future use in dental implant surgery and its learning curve can serve as a reference for dentists.

Accuracy of densitometry of two cone beam computed tomography equipment in comparison with computed tomography

BACKGROUND

The use of oral implants has been growing, and cone beam computerized tomography (CBCT) has become the method of choice for oral and maxillofacial radiology.

OBJECTIVE

To assess the accuracy of bone densitometry in two different CBCT devices in comparison with MDCT (multi-detector CT).

METHODS

Different concentrations of urografin, including 2.5%, 5%, 7.5%, 10%, 12.5%, were prepared, and the Hounsfield unit of these solution was measured by two CBCT devices (SORDEX CRANEX 3D and NEWTOM 5G) and one spiral CT device (SOMATOM SENSATION). Difference of output Hounsfield units in each concentration was compared in three devices. Correlation of devices with increase of urografin dose also was evaluated. Statistical analyses of the data were performed using SPSS18 and Kruskal-Wallis and Mann-Whitney U tests, along with Spearman's correlation coefficient.

RESULTS

The range of gray density for NEWTOM 5G CBCT, SORDEX 3D CBCT, and SOMATOM CT imaging systems was from 781 to 2311, 427 to 1464, and 222 to 994, respectively. There was significant difference between devices in the Hounsfield unit in all urografin concentrations (p<0.001). Also there was a significant correlation between three devices with increasing the urografin dose (p<0.05; r>0.95).

CONCLUSION

Our findings indicated a high correlation and linear relationship between different studied imaging systems. Although utilizing CBCT in the assessment of bone density is useful according to its lower emitted dose and less cost, clinicians should be aware of the issue that the voxel value in CBCT is not as perfect as CT.

Localization of mandibular canal and assessment of the remaining alveolar bone in posterior segment of the mandible with single missing tooth using cone-beam computed tomography: a cross sectional comparative study

Objectives

Localization of the mandibular canal (MC) and measurement of the height and width of the available alveolar bone at the proposed implant site in the posterior segment of the mandible using cone-beam computed tomography (CBCT) in patients with a single missing tooth.

Materials and Methods

A cross-sectional study was performed where CBCT scans of the patients with a single missing tooth in the posterior segment of the mandible—premolar, I (1st) molar, and II (2nd) molar were used. The scans were assessed using OnDemand3D software (version 1.0; CyberMed Inc., Seoul, Korea) for localization of the MC asnd remaining alveolar bone both vertically (from the superior position of the MC to the crest of the alveolar ridge) and horizontally (buccolingual, 3 mm below the crest of the alveolar ridge). The findings were statistically analyzed using independent t-test.

Results

A total of 120 mandibular sites (40 sites for each of the three missing premolar, I molar, and II molar) from 91 CBCT scans were analyzed. The average heights (from the alveolar crest to the superior margin of the MC) at the premolar, I molar, and II molar areas were 15.19±2.12 mm, 14.53±2.34 mm, and 14.21±2.23 mm, respectively. The average widths, measured 3 mm below the crest of the alveolar ridge, at the premolar, I molar, and II molar areas were 6.22±1.96 mm, 6.51±1.75 mm, and 7.60±2.08 mm, respectively. There was no statistically significant difference between males and females regarding the vertical and horizontal measurements of the alveolar ridges.

Conclusion

In the study, the measurements were averaged separately for each of the single missing teeth (premolar, I molar, or II molar), giving more accurate information for dental implant placement.

Clinical and 3-Dimensional Radiographic Evaluation of Autogenous Iliac Block Bone Grafting and Guided Bone Regeneration in Patients With Atrophic Maxilla

PURPOSE

To evaluate the rate of graft resorption in autogenous iliac bone grafting (IBG) and guided bone regeneration (GBR) in patients with atrophic maxillae.

MATERIALS AND METHODS

We performed a retrospective study involving patients requiring implant placement who underwent IBG or GBR. Volumetric changes of the graft sites were evaluated by imaging studies. The primary predictor and outcome variables were augmentation technique and rate of volumetric resorption, respectively. Secondary outcome variables included bone gain, success of grafting, insertion torque of implants, and requirement for vestibuloplasty.

RESULTS

The sample comprised 39 patients (21 with GBR and 18 with IBG). One patient in the IBG group had temporary sensory disturbance at the donor site, and one patient in the GBR group had late exposure of the nonresorbable membrane. The average values of percent volume reduction in the GBR and IBG groups were 12.26% ± 2.35% and 35.94% ± 7.94%, respectively, after healing and 15.87% ± 1.99% and 41.62% ± 6.97%, respectively, at last follow-up. The IBG group exhibited a significantly higher reduction in bone volume than the GBR group at both time points (P = .001). The mean values of horizontal and vertical bone gain after healing in the IBG group were significantly higher than those in the GBR group (P = .006 and P = .001, respectively). The mean implant torque during implant placement in the GBR group was significantly higher than that in the IBG group (P = .024). There was no significant difference in the requirement for vestibuloplasty between the two groups (P > .05).

CONCLUSIONS

Although both hard tissue augmentation approaches provide an adequate volume of bone graft for implant insertion, IBG results in greater graft resorption at maxillary augmented sites than GBR. Clinicians should consider the differences in the extent of graft resorption between the two methods while choosing the treatment approach.

Evaluation of Volumetric Changes of Augmented Maxillary Sinus With Different Bone Grafting Biomaterials

Extensive alveolar bone resorption because of pneumatized maxillary sinus is a common problem that limits dental implant placement. Maxillary sinus floor augmentation (MSFA) is an accepted treatment protocol that provides sufficient bone volume. The aim of this study was to evaluate the percentage of graft volume reduction following MSFA using cone beam computed tomography. In this retrospective study, cone beam computed tomography scans of MSFA were measured to evaluate the volume of the grafted sinus with deproteinized bovine bone (DBB), mineralized allograft (MA), or a mixture of MA and demineralized allograft as a composite. The volumetric changes in sinus augmentation between 2 weeks (T-I) and 6 months (T-II) after operation were analyzed. Thirty-nine patients were included in this study. The average percent volume reduction was 8.14 ± 3.76%, 19.38 ± 9.22%, and 24.66 ± 4.68% for DBB, MA, and composite graft, respectively. A significant graft volume reduction was found between T-I and T-II for all groups (P < 0.01). The DBB group showed the least volume reduction (P < 0.01). Biomaterials can influence the bone graft volume change before implant placement. Deproteinized bovine bone may offer greater volume stability during healing than mineralized and composite allografts.

Marginal and apical bone stability after staged sinus floor augmentation using bone condensing implants with variable-thread design: a two-dimensional analysis

Studies on the vertical stability of augmented bone after sinus lifting differ substantially. In addition, long healing periods are usually advocated prior to implant installation. The purpose of this case series study was to evaluate the changes in bone height after sinus lifting with a bovine-derived xenograft and to evaluate the clinical outcome of bone condensing implants installed after a short healing period. Patients treated during the years 2010-2013 were re-examined using peri-apical radiographs to evaluate the changes in augmented bone height (BH) and marginal bone loss (BL). Fifty-seven of 70 eligible subjects (28 male and 29 female, mean age 56 years) attended for reassessment. Data were available for 53 sinus lifts and 105 implants installed after a mean healing period of 4.6±1.5 months. Implant survival was 99% after a mean time in function of 19±9 months. Baseline BH, BH at implant placement, and final BH were on average 3.87±1.74mm, 13.75±2.12mm, and 13.11±2.12mm, respectively (P<0.001). Mean BL was 0.51±0.65mm. Only limited resorption is to be expected after sinus lifting in the short term. A bone condensing implant can be used in the early healing phase with successful outcomes in terms of implant survival and bone adaptation.

Distortion of digital panoramic radiographs used for implant site assessment

Aims:

This study is conducted to determine the amount of distortion of digital panoramic radiographs.

Materials and Methods:

Panoramic radiographs of all patients who received dental implants in the years 2012 and 2013 were selected from the records at the faculty of dentistry, King Abdulaziz University. Radiographs were analyzed using the R4 Kodak Software for linear measurements of implants length and width. The measurements were compared to the actual size of the implant, and the amount of distortion was calculated.

Results:

A total of 169 implants were analyzed. Horizontally, there was a statistically significant increase of 0.4 mm in width in the radiographic measurement compared to the actual size in the incisor region. Vertically, the sample overall exhibited a decrease by 0.4 mm compared to the actual size. Incisors had the highest difference with a decrease of 1.7 mm in the radiographic measurements compared to actual size. The highest distortion was found in the incisor region for both diameter and length (1.1 and 0.86), respectively.

Conclusion:

Digital panoramic radiographs show minimal to no distortion. The highest distortion is found in the anterior area.

Assessment of the Anterior Loop of the Mental Nerve Using Cone Beam Computerized Tomography Scan

The purpose of this study is to use cone-beam computerized tomography (CBCT) scans with oblique-transverse reconstruction modality to measure and compare the anterior loop length (AnLL) of the mental nerve between gender and age groups and to compare the difference between the right and left sides. Sixty-one female and 61 male CBCT scans were randomly selected for each age group: 21–40, 41–60, and 61–80 years. Both right- and left-side AnLLs were measured in each subject using i-CATVision software to measure AnLLs on the oblique transverse plane using multiplanar reconstruction. The anterior loop was identified in 85.2% of cases, with the mean AnLL of the 366 subjects (732 hemimandibles) being 1.46 ± 1.25 mm with no statistically significant difference between right and left sides or between different gender groups. However, the mean AnLL in the 21–40 year group (1.89 ± 1.35 mm) was larger than the AnLL in the 41–60 year group (1.35 ± 1.19 mm) and the 61–80 year group (1.13 ± 1.08 mm). In conclusion, when placing implants in close proximity to mental foramina, caution is recommended to avoid injury to the inferior alveolar nerve. No fixed distance anteriorly from the mental foramen should be considered safe. Using CBCT scans with the oblique-transverse method to accurately identify and measure the AnLL is of utmost importance in avoiding and protecting its integrity.

Accuracy of computer-guided surgery: A comparison of operator experience

STATEMENT OF PROBLEM

Even though high-precision technologies have been used in computer-guided implant surgery, studies have shown that linear and angular deviations between the planned and placed implants can be expected.

PURPOSE

The purpose of this study was to evaluate the effect of operator experience on the accuracy of implant placement with a computer-guided surgery protocol.

MATERIAL AND METHODS

Ten surgically experienced and 10 surgically inexperienced operators participated in this study. Each operator placed 1 dental implant (Replace Select) on the partially edentulous mandibular model that had been planned with software by following a computer-guided surgery (NobelGuide) protocol. Three-dimensional information of the planned and placed implants were then superimposed. The horizontal and vertical linear deviations at both the apex and platform levels and the angular deviation were measured and compared between the experienced and inexperienced groups with the independent t test with Bonferroni adjustment (α=.01). The magnitude and direction of the horizontal deviations were also measured and recorded.

RESULTS

No significant differences were found in the angular and linear deviations between the 2 groups (P>.01). Although not statistically significant (P>.01), the amount of vertical deviation in the coronal direction of the implants placed by the inexperienced operators was about twice that placed by the experienced operators. Overall, buccal apical deviations were most frequent and of the highest magnitude.

CONCLUSIONS

When a computer-guided protocol was used, the accuracy of the vertical dimension (depth of implant placement) was most influenced by the operator's level of experience.

Does cone-beam CT alter treatment plans? Comparison of preoperative implant planning using panoramic versus cone-beam CT images

PURPOSE

The present study was performed to compare the planning of implant placement based on panoramic radiography (PAN) and cone-beam computed tomography (CBCT) images, and to study the impact of the image dataset on the treatment planning.

MATERIALS AND METHODS

One hundred five partially edentulous patients (77 males, 28 females, mean age: 46 years, range: 26-67 years) seeking oral implant rehabilitation were referred for presurgical imaging. Imaging consisted of PAN and CBCT imaging. Four observers planned implant treatment based on the two-dimensional (2D) image datasets and at least one month later on the three-dimensional (3D) image dataset. Apart from presurgical diagnostic and dimensional measurement tasks, the observers needed to indicate the surgical confidence levels and assess the image quality in relation to the presurgical needs.

RESULTS

All observers confirmed that both imaging modalities (PAN and CBCT) gave similar values when planning implant diameter. Also, the results showed no differences between both imaging modalities for the length of implants with an anterior location. However, significant differences were found in the length of implants with a posterior location. For implant dimensions, longer lengths of the implants were planned with PAN, as confirmed by two observers. CBCT provided images with improved scores for subjective image quality and surgical confidence levels.

CONCLUSION

Within the limitations of this study, there was a trend toward PAN-based preoperative planning of implant placement leading towards the use of longer implants within the posterior jaw bone.

Space closure in the maxillary posterior area through the maxillary sinus

A common dilemma in adult orthodontic treatment is deciding how best to treat missing posterior teeth. One treatment option is to orthodontically close the space. But closure can be difficult, especially if the open space is in the maxillary posterior area, because tooth movement through the maxillary sinus is limited. The increased difficulty of moving teeth in the maxillary sinus is similar to moving a tooth in the atrophic posterior mandibular ridge. If space closure is selected as a treatment method, proper mechanics and light forces should be applied. In this article, we report movement of teeth through the maxillary sinus and discuss various implications related to orthodontic treatment in the maxillary sinus.

Conventional radiography and cross-sectional imaging when planning dental implants in the anterior edentulous mandible to support an overdenture: a systematic review

The objectives for this systematic review were to determine if the pre-operative availability of cross-sectional imaging, such as cone beam CT, has a diagnostic impact, therapeutic impact or impact on patients' outcome when placing two dental implants in the anterior mandible to support an overdenture. The Cochrane Oral Health Group's Trials Register (CENTRAL), MEDLINE® and Embase were searched up to, and including, February 2013. Studies were considered eligible for inclusion if they compared the impact of conventional and cross-sectional imaging when placing dental implants in sites including the anterior mandible. An adapted quality assessment tool was used for the assessment of the risk of bias in included studies. Pooled quantitative analysis was not possible and, therefore, synthesis was qualitative. Of 2374 potentially eligible papers, 5 studies were included. Little can be determined from a synthesis of these studies because of their small number, clinical diversity and high risks of bias. Notwithstanding, it may be tentatively inferred that cross-sectional imaging has a therapeutic impact in the more challenging cases. In terms of impact, this review has found no evidence to support any specific imaging modality when planning dental implant placement in any region of the mouth. Therefore, those who argue that cross-sectional imaging should be used for the assessment of all dental implant sites are unsupported by evidence.

Investigation of bone conditions for orthodontic anchorage plates in the anterior mandible

OBJECTIVES

The clinical success of orthodontic anchorage plates depends on the stability of the miniscrews used for fixation. For good stability, the application site must provide bone of good quantity and quality. This study was performed to analyze bone quantity for orthodontic anchorage plates in the anterior mandible.

PATIENTS AND METHODS

A total of 51 computed tomography (CT) scans of fully dentate patients (mean age 24.0±8.1 years; 27 men and 24 women) were evaluated. Measurements were taken to analyze the total orovestibular and vestibular cortical thickness of the mandibular jawbone at different anterior locations and levels.

RESULTS

Vestibular cortical thickness is generally thinnest within the incisor area on the apex level. Its thickness increases in basal and distal directions. The total orovestibular thickness is also the least on the level of the anterior mandibular apices, becoming thicker toward more basal levels and the posterior teeth.

CONCLUSION

We can reasonably assume that the stability of anchorage plates can be optimized by selecting a position well basal to the apices of the lower incisors, as this area offers enhanced cortical and total jawbone thickness.

Accuracy of linear vertical measurements in posterior mandible on panoramic view

Background:

One of the most frequent concerns encountered in dental implant treatments is inadequate pre-operative planning. Panoramic radiographs are readily accessible and cost efficient. The aim of this study is to assess the accuracy of vertical measurements in mandibular molar and premolar region on panoramic radiography.

Materials and Methods:

Panoramic radiographs were made of a partially edentulous sheep mandible mounted in acryl. Measurements collected from the computer-generated images were compared to measurements made directly on the cross-sectioned hemi-mandibles using t-test. P < 0.05 was considered significant.

Results:

The results show that panoramic image is overestimated in predicting the linear measurements in posterior mandible. By applying the magnification factor of 1.29 the difference became insignificant.

Conclusion:

It seems rational to use panoramic radiography for pre-surgical implant assessment of posterior mandible if a true magnification factor is applied.

How does an error in positioning the template affect the accuracy of implants inserted using a single fixed mucosa-supported stereolithographic surgical guide?

Computer-aided implantology using a single fixed stereolithographic surgical guide involves a sequence of diagnostic and therapeutic events, and errors can creep in at different stages. Taken together, these can be termed the 'total error'. A positioning of the surgical guide on the support surface different to that of the diagnostic template may generate an error that reoccurs with all the implants inserted, and this error can be termed the 'guide positioning error'. The aim of the present study was to measure the deviation between the planned and inserted implants due to this guide positioning error, to evaluate if this error was statistically significant, and concurrently, to assess the influence of the type of arch (upper vs lower jaw) and mucosal thickness on the guide positioning error. Twenty-four subjects were treated and 172 implants inserted. Preoperative and postoperative computed tomography images were compared using Mimics software to determine the total error and guide positioning error. Quantitative data were described; the t-test and Pearson correlation coefficient were used. The guide positioning error was found to affect the accuracy, but was statistically significant only for global coronal deviation (P = 0.038). Arch of support and mucosa thickness did not affect the guide positioning error.

Identification of the mental neurovascular bundle: a comparative study of panoramic radiography and computer tomography

OBJECTIVES

To compare the images of the mental canal in panoramic radiography (PR) and computed tomography (CT) by analyzing the concordance with diagnostic tests and examiners.

MATERIAL AND METHODS

The position of the mental foramen (MF), distance to the lower mandibular border, anterior length of the mental loop (ML), agreement between examiners and diagnostic concordance were registered in 50PR and 50CT.

RESULTS

ML was identified (34.5/41%, PR/CT). PR magnification was 36.6% higher than in CT. The anterior extension and distance to the inferior border of the MF was higher for PR (2-6.2 mm). Inter-examiner agreement on CT was good (κ = 0.628) and very good on PR (κ = 0.845).

CONCLUSION

There is a magnification (36.6%) of the images in PR with respect to the CT. Identification of MF and ML is not related to the bone quality. Inter-examiner agreement is better on PR.

Reliability of two different presurgical preparation methods for implant dentistry based on panoramic radiography and cone-beam computed tomography in cadavers

PURPOSE

Special care is necessary to avoid invading important anatomic structures during surgery when presurgical planning is made based on radiographs. However, none of these types of radiography represents a perfect modality. The purpose of this study was to determine the reliability of presurgical planning based on the use of two types of radiographic image (digital panoramic radiography [DPR] and cone-beam computed tomography [CBCT]) by beginner dentists to place implants, and to quantify differences in measurements between radiographic images and real specimens.

METHODS

Ten fresh cadavers without posterior teeth were used, and twelve practitioners who had no experience of implant surgery performed implant surgery after 10 hours of basic instruction using conventional surgical guide based on CBCT or DPR. Two types of measurement error were evaluated: 1) the presurgical measurement error, defined as that between the presurgical and postsurgical measurements in each modality of radiographic analysis, and 2) the measurement error between postsurgical radiography and the real specimen.

RESULTS

The mean presurgical measurement error was significantly smaller for CBCT than for DPR in the maxillary region, whereas it did not differ significantly between the two imaging modalities in the mandibular region. The mean measurement error between radiography and real specimens was significantly smaller for CBCT than for DPR in the maxillary region, but did not differ significantly in the mandibular region.

CONCLUSIONS

Presurgical planning can be performed safely using DPR in the mandible; however, presurgical planning using CBCT is recommended in the maxilla when a structure in a buccolingual location needs to be evaluated because this imaging modality supplies buccolingual information that cannot be obtained from DPR.

Pre- and postoperative assessment of sinus grafting procedures using cone-beam computed tomography compared with panoramic radiographs

OBJECTIVES

The present study evaluated the clinical validity of cone-beam computed tomography (CBCT) scans in comparison to panoramic radiographs regarding preoperative implant planning in combination with sinus grafting procedures.

MATERIALS AND METHODS

Preoperative assessment of the maxillary sinuses and implant planning using panoramic radiographs and CBCT scans was performed on 16 sinuses (13 patients) and comprised choice of treatment, timing of implant placement, sinus morphology, level of confidence, complication prediction and graft volume assessment. Six examiners were involved in the study.

RESULTS

In the majority of cases there was a concordance between the treatment type based on either panoramic radiographs or CBCT. If any difference was found, this was due to an overestimation of bone quantity and quality on panoramic radiographs. The assessment of sinus morphology showed a significantly higher detection rate of sinus mucosal hypertrophy on CBCT. The most appealing result is a significant increase in surgical confidence and a significantly better prediction of complications when using CBCT.

CONCLUSIONS

A preoperative planning based on CBCT seems to improve sinus diagnostics and surgical confidence.

The effects of location of alveolar crest on the vertical bone heights on panoramic radiographs

OBJECTIVES

This study aimed to show that the horizontal relationship between the mandibular canal and the alveolar crest can influence the available bone height (ABH) measurement on panoramic radiographs.

METHODS

92 mandibular edentulous sites of panoramic computed radiographs and reformatted CT images of 77 patients were used. Selected CT images were categorized into four types according to the relative location of the peak of the alveolar crest to the mandibular canal. One oral and maxillofacial radiologist measured the ABH twice on both imaging modalities with an interval of 7 days and compared the measurement differences according to the type.

RESULTS

The absolute average value of the differences in measurement between the values of ABHs on panoramic images and CT images was 0.97 mm. Significant difference was found only between the mean values of ABHs for Type 1 (0.60 mm), where the alveolar crest is located in the buccal side or central area with respect to the mandibular canal, and Type 4 (1.46 mm), where the alveolar crest is in the lingual side to the mandibular canal (p < 0.05).

CONCLUSIONS

The relative horizontal location of the alveolar crest with respect to the mandibular canal affected the ABH measurement on panoramic radiographs. In particular, ABH is overestimated when there has been resorption of the buccal aspect of the ridge, moving the alveolar crest lingually.

Evaluation of the accuracy of panoramic radiography in linear measurements of the jaws

BACKGROUND/OBJECTIVE

Panoramic radiography has a great place among imaging techniques because of its enormous advantages. One of the characteristics of an ideal imaging technique is to supply precise measurement. The purpose of the current study was to evaluate the accuracy of linear measurements of the jaws on panoramic radiographs.

PATIENTS AND METHODS

In this study, the vertical distances between the metal markers were measured by panoramic radiography in seven sites of two skulls in various head positions. Then the radiographic measurements were compared with the actual values.

RESULTS

Eighty three percent of the measurements were underestimated, 8.5% were overestimated on panoramic radiography and 8.5% of the measurements had no difference with the real measurements. Overestimation was not greater than 1 mm. The difference between actual and radiographic measurements was less in the posterior areas and in the mandible . In all head positions, the greatest difference between actual and radiographic measurements occurred in the anterior area.

CONCLUSION

Based on the results of this study, linear measurements on panoramic radiography are more reliable in the posterior areas and may be used in early clinical measurements.

Computer-guided surgery in implantology: review of basic concepts

The aim of the present study was to conduct a critical literature review about the technique of computer-guided surgery in implantology to highlight the indications, purposes, immediate loading of implants and complications, protocol of fabrication, and functioning of virtual planning software. This literature review was based on OLDMEDLINE and MEDLINE databases from 2002 to 2010 using the key words "computer-guided surgery" and "implant-supported prosthesis." Thirty-four studies regarding this topic were found. According to the literature review, it was concluded that the computer-assisted surgery is an excellent treatment alternative for patients with appropriate bone quantity for implant insertion in complete and partially edentulous arches. The Procera Nobel Guide software (Nobel Biocare) was the most common software used by the authors. In addition, the flapless surgery is advantageous for positioning of implants but with accurate indication. Although the computer-guided surgery may be helpful for virtual planning of cases with severe bone resorption, the conventional surgical technique is more appropriate. The surgical guide is important for insertion of the implants regardless of the surgical technique, and the success of immediate loading after computer-guided surgery depends on the accuracy of clinical and/or laboratorial steps.