Timo Dreiseidler

Prevalence of pathologic findings in the maxillary sinus in cone-beam computerized tomography

OBJECTIVE The aim of this study was to assess the prevalence of pathologic findings in the maxillary sinus by using cone-beam computerized tomography (CBCT). STUDY DESIGN One thousand twenty-nine consecutive CBCT scans were retrospectively inspected for pathologic findings in the maxillary sinus by 3 observers. Findings were differentiated by mucosal thickening, partial opacification with liquid accumulation, total opacification, and polypoidal mucosal thickening. Position and diameter of the maxillary sinus ostium were assessed. Correlations for pathologic findings and the factors of age and gender were calculated. Patients with clinical manifestations of sinusitis or total opacification in either sinus were reevaluated. RESULTS A total prevalence for pathologies in the maxillary sinus of 56.3% was found in this study. The most frequent pathology was mucosal thickening. Patients >60 years of age showed significantly more pathologies in the maxillary sinus (P = .02), and male patients showed significantly more pathologies than female patients (P = .01). Clinical signs of sinusitis could be confirmed on CBCT images for all patients. CONCLUSIONS Pathologies in the maxillary sinus are frequently found in CBCT imaging and have to be treated or followed-up accordingly. CBCT is applicable for diagnosis and treatment planning of clinically present sinusitis.

Accuracy of a newly developed integrated system for dental implant planning

OBJECTIVES To evaluate the accuracy of the first integrated system for cone-beam CT (CBCT) imaging, dental implant planning and surgical template-aided implant placement. MATERIALS AND METHODS On the basis of CBCT scans, a total of 54 implant positions were planned for 10 partially edentulous anatomical patient-equivalent models. Surgical guides were ordered from the manufacturer (SICAT). Two different types of guidance were assessed: for assessment of the SICAT system inherent accuracy vendors titanium sleeves of 2 mm internal diameter and 5 mm length were utilized for pilot drills. The guide sleeves of the NobelGuide system were implemented for fully guided surgery and implant insertion. Deviations perpendicular to the implant axes at the crestal and apical end, as well as the angle deviations between the virtual planning data and the surgical results, were measured utilizing a follow-up CBCT investigation and referential marker-based registration. RESULTS The SICAT system inherent mean deviation rates for the drilled pilot osteotomies were determined to be smaller than 500 mum even at the apical end. Mean angle deviations of 1.18 degrees were determined. Utilizing the NobelGuide sleeve-in-sleeve system for fully guided implant insertion in combination with the investigated template technology enabled to insert dental implants with the same accuracy. Crestal deviations, in general, were significantly lower than the apical deviations. CONCLUSION Although hardly comparable due to different study designs and measurement strategies, the investigated SICAT systems inherent accuracy corresponds to the most favourable results for computer-aided surgery systems published so far. In combination with the NobelGuide surgical set for fully guided insertion, the same accuracy level could be maintained for implant positioning.

Computer-assisted orthognathic surgery: waferless maxillary positioning, versatility, and accuracy of an image-guided visualisation display

There may well be a shift towards 3-dimensional orthognathic surgery when virtual surgical planning can be applied clinically. We present a computer-assisted protocol that uses surgical navigation supplemented by an interactive image-guided visualisation display (IGVD) to transfer virtual maxillary planning precisely. The aim of this study was to analyse its accuracy and versatility in vivo. The protocol consists of maxillofacial imaging, diagnosis, planning of virtual treatment, and intraoperative surgical transfer using an IGV display. The advantage of the interactive IGV display is that the virtually planned maxilla and its real position can be completely superimposed during operation through a video graphics array (VGA) camera, thereby augmenting the surgeons 3-dimensional perception. Sixteen adult class III patients were treated with by bimaxillary osteotomy. Seven hard tissue variables were chosen to compare (ΔT1-T0) the virtual maxillary planning (T0) with the postoperative result (T1) using 3-dimensional cephalometry. Clinically acceptable precision for the surgical planning transfer of the maxilla (<0.35 mm) was seen in the anteroposterior and mediolateral angles, and in relation to the skull base (<0.35°), and marginal precision was seen in the orthogonal dimension (<0.64 mm). An interactive IGV display complemented surgical navigation, augmented virtual and real-time reality, and provided a precise technique of waferless stereotactic maxillary positioning, which may offer an alternative approach to the use of arbitrary splints and 2-dimensional orthognathic planning.

The role of clinical versus histopathological staging in patients with advanced oral squamous cell carcinoma treated with neoadjuvant radiochemotherapy followed by radical surgery

INTRODUCTION Several studies have questioned the prognostic accuracy of the TNM system for oral cancer since neither patients comorbidity, specific tumor related factors nor multimodal treatment regimens such as preoperative radiochemotherapy (RCT) are incorporated. The present study was performed in order to evaluate the prognostic impact of cTNM and ypTNM in oral cancer patients treated with preoperative RCT and resection. METHODS In this retrospective analysis a total of 139 patients (103 male, 36 female, average age 56.8 years) with oral squamous cell carcinoma (UICC II-IVb) were included. Treatment consisted of concomitant RCT with 39.6 Gy radiations and Carboplatin (cumulative dose 300 mg/m(2)) during the first week of radiation, as well as surgical tumor resection and neck dissection. RESULTS During the mean follow up of 88.9 months 86 patients (61.9%) died. Locoregional recurrences occurred in 41 patients (29.5%). The 5 years overall survival rate was 45.5%. In univariate analysis margin status, ypT, ypN and ypUICC as well as complete pathological response revealed statistical significance on overall survival. In multivariate analysis ypT, ypN and margin status showed independent prognostic impact in our cohort. Neither cT nor cN provided statistical association with overall survival. CONCLUSION Results indicate that the clinical staging status of advanced oral cancer prior to preoperative RCT and resection should be interpreted with caution in terms of prognosis.

The influence of body mass index, age, implants, and dental restorations on image quality of cone beam computed tomography

OBJECTIVE The aim was to determine the influence of patient age, gender, body mass index (BMI), amount of dental restorations, and implants on image quality of cone-beam computerized tomography (CBCT). METHODS Fifty CBCT scans of a preretail version of Galileos (Sirona, Germany) were investigated retrospectively by 4 observers regarding image quality of 6 anatomic structures, pathologic findings detection, subjective exposure quality, and artifacts. Patient age, BMI, gender, amount of dental restorations, and implants were recorded and statistically tested for correlations to image quality. RESULTS A negative effect on image quality was found statistically significantly correlated with age and the amount of dental restorations. None of the investigated image features were garbled by any of the investigated influence factors. CONCLUSIONS Age and the amount of dental restorations appear to have a negative impact on CBCT image quality, whereas gender and BMI do not. Image quality of mental foramen, mandibular canal, and nasal floor are affected negatively by age but not by the amount of dental restorations. Further studies are required to elucidate influence factors on CBCT image quality.

Accuracy of cone beam computed tomography in assessing peri‐implant bone defect regeneration: a histologically controlled study in dogs

OBJECTIVE To assess the accuracy of cone-beam computed tomography (CBCT) in terms of buccal bone-wall configuration and peri-implant bone defect regeneration after guided bone regeneration (GBR). MATERIAL AND METHODS Titanium implants were inserted into standardized box-shaped defects in the mandible of 12 foxhounds. Defects of one side were augmented following the principle of GBR, while the other side was left untreated. Radiological evaluation was performed using CBCT and compared with histomorphometrical measurements of the respective site serving as a validation method. RESULTS Non-augmented control sites providing a horizontal bone width (BW) of<0.5 mm revealed a significantly lower accuracy between the radiological and the histological evaluation of the buccal defect depth (1.93 ± 1.59 mm) compared with the group providing a BW of >0.5 mm (0.7 ± 0.7 mm) (P<0.05, Mann-Whitney U-test). In GBR-treated defects, the subgroup <0.5 mm (1.49 ± 1.29 mm) revealed a significantly higher difference between CBCT and histology compared with >0.5 mm (0.82 ± 1.07) (P>0.05, Mann-Whitney U-test). However, a radiological discrimination between original bone, integrated and non-integrated bone substitute material was not reliable. Additionally, it was found that a minimum buccal BW of 0.5 mm was necessary for the detection of bone in radiology. CONCLUSION The evaluation of peri-implant bone defect regeneration by means of CBCT is not accurate for sites providing a BW of <0.5 mm. Moreover, a safe assessment of the success of the GBR technique is not possible after the application of a radiopaque bone substitute material.

Salivary calculus diagnosis with 3-dimensional cone-beam computed tomography

OBJECTIVE The objective of this study was to evaluate cone-beam CT (CBCT) diagnoses of sialoliths in the major salivary glands. STUDY DESIGN Twenty-nine CBCT images containing salivary calculi were retrospectively evaluated for image quality and artifact influence. Additionally, the reproducibility of calculus measurement and the differences between CBCT measurements and ultrasonography (US) and histomorphometry (HM) measurements were determined. Diagnostic sensitivity and specificity calculations were based on the observations of 3 masked clinicians, who reviewed a total of 58 CBCT volumes. RESULTS Salivary calculi were sufficiently visualized in all patients. Metal artifacts were detected in images of 7 patients, and movement artifacts in 2. CBCT calculi measurements were highly reproducible, with mean differences of less than 350 microm. Mean CBCT measurements of calculi diameters differed from mean US measurements by approximately 500 microm and differed from mean HM measurements by approximately 1 mm. For calculus diagnoses, the mean sensitivity and specificity were both 98.85%. CONCLUSION Although poor image qualities and artifacts can reduce diagnostic information, salivary calculi can be evaluated adequately with CBCT. CBCT measurements of calculi are highly reproducible and differ little from measurements made with US and HM. Diagnostic sensitivity and specificity levels with CBCT are as high as or higher than those obtained with other diagnostic methods. Because of its high diagnostic-information-to-radiation-dose ratio, CBCT is the preferable imaging modality for salivary calculus diagnosis.

Computer-aided manufacturing technologies for guided implant placement.

Implant treatment increasingly focuses on the reduction of treatment time and postoperative impairment. The improvement of 3D dental diagnosis by ConeBeam computed tomography allows detailed preparation for the surgical placement of dental implants under prosthetic considerations. While the first generation of implant planning software used high-contrast multislice computed tomography, software that has been specifically designed for ConeBeam computed tomography is now available. Implant placement can be performed using surgical guides or under the control of optical tracking systems. Surgical guides are more commonly used in private office owing to their availability. The accuracy for both techniques is clinically acceptable for achieving implant placement in critical anatomical indications. When using prefabricated superstructures and in flapless surgery, special abutments or an adjusted workflow are still necessary to compensate misfits of between 150 and 600 µm. The proposition to ensure proper implant placement by dentists with limited surgical experience through the use of surgical guides is unlikely to be successful, because there is also a specific learning curve for guided implant placement. Current and future development will continue to decrease the classical laboratory-technician work and will integrate the fabrication of superstructures with virtual treatment planning from the start.

Combined-modality treatment in advanced oral squamous cell carcinoma: Primary surgery followed by adjuvant concomitant radiochemotherapy.

AbstractBackgroundThe efficacy of adjuvant radiochemotherapy (RCT) in patients with advanced stage head and neck carcinoma has been proven in prospective randomized trials. However, these trials focused on different head and neck sites. Specific analyses for treatment effects in squamous cell carcinoma of the oral cavity (OSCC) are missing. We evaluated our experiences with adjuvant concomitant RCT in advanced OSCC to compare the results with other treatment schemes using adjuvant RCT.Patients and MethodsA total of 183 patients with OSCC of UICC stages II–IVb were reviewed retrospectively. All patients were treated with radical surgery followed by adjuvant, conventional fractionated concomitant RCT using carboplatin. Overall survival was plotted by Kaplan–Meier analysis. Prognostic factors were identified through univariate and multivariate analysis.ResultsUnivariate analysis showed a significant impact of T, N, and UICC stage, histopathologic grading, surgical margins, extracaspular spread (ECS), and lymphangiosis carcinomatosa on overall survival (Table 3). Patients with stage IVa had a higher 5-year overall survival rate (42.8%) than patients with stage IVb (25.0%) (Figure 1). The differences were significant in multivariate analysis (p = 0.033) (Table 4).ConclusionAdjuvant concomitant RCT is an effective treatment in patients with advanced stage OSCC. However, it remains unclear, which patients should be treated with adjuvant RCT. For patients with stage IVb, adjuvant RCT yields poor results. Prospective randomized trials are needed to confirm which patients should be treated with adjuvant RCT.ZusammenfassungHintergrundDie Wirksamkeit der adjuvanten Radiochemotherapie bei fortgeschrittenen Kopf-Hals-Karzinomen wurde in prospektiven randomisierten Studien nachgewiesen. Jedoch bezogen sich diese Untersuchungen auf alle Regionen des Kopf-Hals-Bereiches. Spezielle Untersuchungen zur Wirksamkeit bei Plattenepithelkarzinomen der Mundhöhle fehlen. Wir haben unsere Erfahrungen mit adjuvanter Radiochemotherapie bei oralen Plattenepithelkarzinomen ausgewertet und mit anderen Behandlungsprotokollen mit adjuvanter Radiochemotherapie verglichen.Methoden183 Patienten mit oralen Plattenepithelkarzinomen der Stadien II–IVb wurden retrospektiv ausgewertet. Alle Patienten wurden mit einer radikalen Resektion, gefolgt von einer konventionell fraktionierten simultanen Radiochemotherapie mit Carboplatin behandelt. Das Gesamtüberleben wurde mit dem Kaplan-Meier-Verfahren ermittelt. Prognostische Faktoren wurden univariat und multivariat analysiert.ErgebnisseUnivariat zeigte sich ein signifikanter Einfluss von T-, N- und UICC-Klassifikation, von histopathologischen Gradings, Resektionsrändern, von extrakapsulärem Wachstum und Lymphangiosis carcinomatosa auf das Gesamtüberleben (Tabelle 3). Patienten im Stadium IVa hatten eine höhere 5-Jahres-Überlebensrate (42,8%) als Patienten im Stadium IVb (25,0%) (Abbildung 1). Die Unterschiede waren multivariat signifikant (p = 0,003) (Tabelle 4).SchlussfolgerungAdjuvante Radiochemotherapie ist eine effektive Behandlungsmethode bei fortgeschrittenen oralen Platten epithelkarzinomen. Es ist jedoch nicht klar, welche Patienten eine adjuvante Radiochemotherapie erhalten sollen. Für Patienten im Stadium IVb zeigten sich schlechte Ergebnisse. Prospektive randomisierte Studien werden benötigt, um zu identifizieren, welche Patienten mit einer adjuvanten Radiochemotherapie behandelt werden sollen.

Registration accuracy of three‐dimensional surface and cone beam computed tomography data for virtual implant planning

OBJECTIVE Virtual wax-ups based on three-dimensional (3D) surface models can be matched (i.e. registered) to cone beam computed tomography (CBCT) data of the same patient for dental implant planning. Thereby, implant planning software can visualize anatomical and prosthetic information simultaneously. The aim of this study is to assess the accuracy of a newly developed registration process. MATERIAL AND METHODS Data pairs of CBCT and 3D surface data of 16 patients for dental implant planning were registered and the discrepancy between the visualized 3D surface data and the corresponding CBCT data were measured on 64 teeth at seven points by two investigators in two iterations with a total of 1792 measurements. RESULTS All data pairs were matched successfully and mean distances between CBCT and 3D surface data were between 0.03(±0.33) and 0.14(±0.18) mm. At two of seven measuring points, statistically significant correlations were determined between the measured error and the presence and type of restorations. Registration errors in maxilla and mandible were not statistically significantly different. CONCLUSION According to the results of this study, registration of 3D surface data and CBCT data works reliably and is sufficiently accurate for dental implant planning. Thereby, barium-sulfate scanning templates can be avoided and dental implant planning can be accomplished fully virtual.