Michael M. Bornstein

Cone beam computed tomography in implant dentistry: recommendations for clinical use

BackgroundIn implant dentistry, three-dimensional (3D) imaging can be realised by dental cone beam computed tomography (CBCT), offering volumetric data on jaw bones and teeth with relatively low radiation doses and costs. The latter may explain why the market has been steadily growing since the first dental CBCT system appeared two decades ago. More than 85 different CBCT devices are currently available and this exponential growth has created a gap between scientific evidence and existing CBCT machines. Indeed, research for one CBCT machine cannot be automatically applied to other systems.MethodsSupported by a narrative review, recommendations for justified and optimized CBCT imaging in oral implant dentistry are provided.ResultsThe huge range in dose and diagnostic image quality requires further optimization and justification prior to clinical use. Yet, indications in implant dentistry may go beyond diagnostics. In fact, the inherent 3D datasets may further allow surgical planning and transfer to surgery via 3D printing or navigation. Nonetheless, effective radiation doses of distinct dental CBCT machines and protocols may largely vary with equivalent doses ranging between 2 to 200 panoramic radiographs, even for similar indications. Likewise, such variation is also noticed for diagnostic image quality, which reveals a massive variability amongst CBCT technologies and exposure protocols. For anatomical model making, the so-called segmentation accuracy may reach up to 200xa0μm, but considering wide variations in machine performance, larger inaccuracies may apply. This also holds true for linear measures, with accuracies of 200xa0μm being feasible, while sometimes fivefold inaccuracy levels may be reached. Diagnostic image quality may also be dramatically hampered by patient factors, such as motion and metal artefacts. Apart from radiodiagnostic possibilities, CBCT may offer a huge therapeutic potential, related to surgical guides and further prosthetic rehabilitation. Those additional opportunities may surely clarify part of the success of using CBCT for presurgical implant planning and its transfer to surgery and prosthetic solutions.ConclusionsHence, dental CBCT could be justified for presurgical diagnosis, preoperative planning and peroperative transfer for oral implant rehabilitation, whilst striving for optimisation of CBCT based machine-dependent, patient-specific and indication-oriented variables.

Three-dimensional radiographic evaluation of root migration patterns 4-8.5 years after lower third molar coronectomy: a cone beam computed tomography study

This prospective study in patients with a follow-up of 4-8.5years aimed to describe the long-term, three-dimensional changes of coronectomized lower third molar roots. Pre- and postoperative cone beam computed tomography (CBCT) scans were compared. The distance of root migration, the direction of root translation and rotation, and the amount of bone regeneration at the adjacent second molar and superficially to the third molar root were recorded. Age, gender, time elapsed following surgery, the status of the retained root including, impaction pattern and depth of impaction were tested to check if they were influencing factors for the above outcomes. A total of 57 coronectomized third molars from 44 patients were included. The distance of the mean root migration was 2.82mm, and they predominantly translated mesially (76.8%). Age negatively correlated with the distance of migration. Root remnants with a soft tissue coverage had less bone regenerated at the adjacent second molar (1.27mm vs. 2.95mm) in comparison to their impacted counterparts. Based on the present radiographic results and the absence of any pathological findings, coronectomy can be recommended for selected cases of third molar removal as a safe procedure with favourable long-term outcomes.

A randomized controlled clinical and histopathological trial comparing excisional biopsies of oral fibrous hyperplasias using CO2 and Er:YAG laser

This study was conducted in order to compare clinical and histopathological outcomes for excisional biopsies when using pulsed CO2 laser versus Er:YAG laser. Patients (nu2009=u200932) with a fibrous hyperplasia in the buccal mucosa were randomly allocated to the CO2 (140xa0Hz, 400xa0μs, 33xa0mJ) or the Er:YAG laser (35xa0Hz, 297xa0μs, 200xa0mJ) group. The duration of excision, intraoperative bleeding and methods to stop the bleeding, postoperative pain (VAS; ranging 0–100), the use of analgesics, and the width of the thermal damage zone (μm) were recorded and compared between the two groups. The median duration of the intervention was 209xa0s, and there was no significant difference between the two methods. Intraoperative bleeding occurred in 100% of the excisions with Er:YAG and 56% with CO2 laser (pu2009=u20090.007). The median thermal damage zone was 74.9xa0μm for CO2 and 34.0xa0μm for Er:YAG laser (pu2009<u20090.0001). The median VAS score on the evening after surgery was 5 for the CO2 laser and 3 for the Er:YAG group. To excise oral soft tissue lesions, CO2 and Er:YAG lasers are both valuable tools with a short time of intervention and postoperative low pain. More bleeding occurs with the Er:YAG than CO2 laser, but the lower thermal effect of Er:YAG laser seems advantageous for histopathological evaluation.

Application of Real-Time Surgical Navigation for Zygomatic Implant Insertion in Patients With Severely Atrophic Maxilla

PURPOSEnComputer-aided treatment technology has extended its applications to oral implantology. This report describes the authors initial clinical experience on the application of a commercially available navigation system (VectorVision) in zygomatic implant (ZI) insertion in the severely atrophic maxilla.nnnMATERIALS AND METHODSnThis was a retrospective longitudinal study. Eligible patients with maxillary edentulism who were treated with ZI placement were enrolled. Treatment planning was performed on the computer based on previously obtained 3-dimensional imaging data. The surgical procedure was carried out under the guidance of a surgical navigation system. The outcome variable was safety and additional variables were ZI survival rate and radiologic bone-to-implant contact (rBIC) area in the zygoma. Statistical analysis was performed with SPSS 16.0 for Windows (SPSS, Inc, Chicago, IL).nnnRESULTSnFifteen patients (8 men, 7 women; age range, 30 to 69xa0yr; average age, 43xa0±xa03.5xa0yr) were eligible for the study and were enrolled from May 2015 through September 2016. Of the included patients, each of 4 patients received 1 ZI on each side of the zygomatic bone and 2 to 4 standard implants in the edentulous anterior maxilla; the other 11 received a ZI quad approach without standard implant insertion. All ZIs were anchored in the site of the maxillary alveolar process and zygomatic bone, and no critical anatomic structure injuries occurred during insertion and postoperative radiographic examination. All ZIs achieved osseointegration, for an overall survival rate of 100% after early healing. The overall rBIC area of ZIs in the study was 4.1 to 24.7xa0mm (average, 14.5xa0±xa04.6xa0mm).nnnCONCLUSIONnFor the limited clinical cases treated in this study, the procedure for ZI placement was feasible and reliable with the guidance of the surgical navigation system. In addition, the potential risk of complications was minimized and ZIs were placed to make the best possible use of the available bone volume.

Diagnosis of tooth ankylosis using panoramic views, cone beam computed tomography, and histological data: a retrospective observational case series study

ObjectivesnThe aim of this study was to determine whether cone beam computed tomography is a reliable radiological method to diagnose tooth ankylosis.nnnMaterials and methodsnA series of teeth clinically diagnosed as ankylosed were collected after extraction in a private practice from 2009 to 2015 and analyzed retrospectively. Inclusion criteria comprised permanent molars extracted due to failed tooth eruption in the absence of any visible mechanical obstruction, existing panoramic view (PV), and cone beam computed tomography (CBCT) and histological sections of sufficient quality. The CBCT scans and PVs were evaluated twice for signs of ankylosis by two independent observers using the following score: clear signs, possible signs, and no signs. The histological sections were evaluated and graded similarly to the radiographs by a specialist blinded to the radiographs and treatment.nnnResultsnOut of an initial group of 22 patients, 9 subjects with 10 affected teeth were included for final evaluation. The age ranged from 8.3 to 17 years. No agreement was seen in comparing the PV scores to the histological sections. Fair to moderate agreement was seen in comparing the CBCT scores to the histological sections. All histologically confirmed ankylosis were detected in CBCT by both observers but some false positive results were found.nnnLimitationnOnly a small sample size was available as the disorder is rare. It is difficult to distinguish ankylosis from primary failure of eruption.nnnConclusionnCBCT images can be a useful adjunctive diagnostic tool to diagnose ankylosed teeth, but cannot be recommended as a single diagnostic modality as false positive results were found.

Frequency, location, and association with dental pathology of mucous retention cysts in the maxillary sinus. A radiographic study using cone beam computed tomography (CBCT)

ObjectivesThe purpose of the present study was to evaluate the frequency, locations, and dimensions of mucous retention cysts of the maxillary sinus and analyze potential associated dental pathology.Materials and methodsA total of 156 cone beam computed tomography (CBCT) scans were included in the analysis, resulting in an evaluation of 310 maxillary sinuses. The presence of mucous retention cysts (MRC) manifesting as dome-shaped radiopacities in the sinus was diagnosed. Their locations were recorded, and dimensions (mm) were measured in coronal and sagittal/axial slices. The patients were grouped into (a) patients/sinuses with MRCs (test), and (b) patients/sinuses with healthy or any other changes (control) for further comparison and evaluation.ResultsThere were 40 sinuses (12.9%) with a presence of a total of 56 MRCs. The mean age of involved patients was 29.0xa0years. The analysis showed that gender, age, sinus side, status of dentition, endodontic status, and periodontal status did not have a significant influence on the presence of MRCs when compared between test and control groups. Age and endodontic status exhibited a significant association with cyst location.ConclusionsMost of the sinuses analyzed (79.5%) did not present any MRC, and only 28.6% of the cysts diagnosed were found on the floor of the maxillary sinus. The mean dimension of the MRCs measured 6.28xa0±xa02.93xa0mm. No influencing factors on the presence or absence of MRCs were found in the present study.Clinical relevanceMost MRCs were not located on the floor of maxillary sinus. Future studies should assess their impact on surgical interventions in the sinus.

Patient-reported outcome measures of edentulous patients restored with implant-supported removable and fixed prostheses: A systematic review

OBJECTIVEnThe aim of this systematic review was to compare patient-reported outcomes measures (PROMs) of implant-supported fixed complete dentures (IFCDs) and overdentures (IODs).nnnMATERIAL AND METHODSnPubMed, Cochrane Library, EMBASE, Scopus and Web of Science were searched, complemented by manual search. Studies published in English up to November 2016 comparing removable with fixed implant-supported prosthesis on fully edentulous patients were included. The review focused on impact on patients oral health-related quality of life (OHRQoL), satisfaction or other patient-reported outcomes measures.nnnRESULTSnOf 1,563 initially screened articles, 13 studies including 8 prospective and 5 retrospective studies fulfilled the inclusion criteria. OHRQoL and patient satisfaction were the most common PROMs. When evaluating the levels of evidence, five of thirteen studies were graded as level III and seven reached level II. The only randomized control trial was rated as Ib. The methods used to evaluate PROMs were heterogeneous among studies, and there was a lack of standardization in the measurements employed. In general, IFCD and IOD showed no significant differences when compared for PROMs, with a slight trend of IFCD being superior to IOD in most included studies. However, conflicting results were observed in many aspects such as chewing function, phonetics-related function, overall satisfaction and aesthetics.nnnCONCLUSIONSnInconsistent results were observed in PROMs when comparing IFCD and IOD for fully edentulous patients. A guideline for standardizing the assessment of PROMs in clinical research is needed in order to produce more meaningful evidence-based information.

The nasopalatine canal, a limiting factor for temporary anchorage devices: a cone beam computed tomography data study

ObjectivesnThere is only little knowledge on topographical predispositions of the nasopalatine canal as a limiting factor for insertion of mid-palatal temporary anchorage devices (TAD). The purpose of the study was to assess the course of the nasopalatine canal, the adjacent vertical bone quantity, and whether it might differ among vertical facial types, using pre-existing cone beam computed tomography (CBCT) scans.nnnMaterial and MethodsnOut of a consecutive sample collected from April 2008 to August 2012, only patient data depicting both upper and lower jaw completely were evaluated retrospectively. The linear measurements were taken on the respective midsagittal view perpendicular to the palate at the level of 1st molar/2nd premolar (5/6), 2nd premolar/1st premolar (4/5), and 1st premolar/canine (3/4). Screen-prints were used to measure the inclination of the nasopalatine canal in relation to the maxillary jaw base. Maxillary and mandibular divergence was assessed on rendered lateral cephalograms.nnnResultsnOut of 3869 pre-existing consecutive CBCT scans, data from 398 patients met the inclusion criteria and could be extracted. The mean vertical bone was 4.09 mm at the 5/6 level, 5.22 mm at the 4/5 level, and 3.14 mm at the 3/4 level, respectively. A statistically significant negative correlation exists between jaw divergence and the canal angulation with regard to the maxillary base. A statistically significant negative correlation exists between the canal angulation and vertical bone measurements at the 4/5 and 3/4 levels.nnnConclusionsnVertical bone volume is sufficient at 4/5 level for TAD placement, and bares only a small risk for neuro-sensory impairment. Therefore, only in rare cases a CBCT is justified for palatal implant placement. The course of the nasopalatine canal is negatively correlated with the vertical skeletal facial pattern pointing to the fact that in hypodivergent patients a TAD might be placed in a more distal or paramedian region.

Patent nasopalatine ducts: an update of the literature and a series of new cases

PurposeThe objective of this review is to present an update and summary of clinical findings of cases with a patent nasopalatine duct (NPD) reported in the literature from 1881 to 2016.MethodsPrevious articles and reviews about patent NPDs were studied and copies of all original publications were obtained for data verification. Furthermore, a literature search was conducted. In addition, the study sample was complemented with four cases recently seen in our institution.ResultsTen out of 67 published cases were to be excluded for this analysis due to misinterpretation or misreporting in previous articles. Overall, 57 cases with NPD patency could be analyzed. Males outnumbered females in a ratio of 2:1. The mean age (when this information was available) was 34.1u2009±u200917.6xa0years (range 6–69xa0years). NPDs were located bilaterally (60%), unilaterally (20%) or centrally (20%). Complete or partial patency was reported in 73.9 and 26.1%, respectively. 74.1% of patients presented a variety of clinical signs and symptoms. The ability of the patient to produce a squeaky or whistling sound was the most frequent clinical finding (23.8%).ConclusionsCaution must be exercised when reading review articles about NPD patency since wrong data have been copied in several subsequent publications. Since epidemiological data are missing with regard to patent NPDs, age and gender predilections are not warranted. Bilateral occurrence and full patency were prevailing features in the evaluated case reports of patent NPDs.

CBCT Imaging of Sinonasal Disease

In dental and maxillofacial cone beam computed tomographic (CBCT) imaging of the mid-facial region, it is highly likely that clinicians will observe various radiologic findings involving the paranasal sinuses. Dentists using CBCT are responsible for interpreting not only the radiologic findings needed for a specific dental task (e.g., implant treatment planning, detect periapical pathologies of posterior teeth in the maxilla) but also the structures, anatomic variability, and common diseases associated with the maxillary sinus. The purpose of this Chapter is to describe specific radiologic patterns indicative of sinonasal pathology, recommend CBCT specific imaging and display protocols, and provide guidelines for systematic interpretation of the paranasal sinuses on CBCT.