Radiochromic films for dental CT dosimetry: a feasibility study.

Dental CT dose evaluations are commonly performed using thermoluminescent dosimeters (TLD) inside anthropomorphic phantoms. Radiochromic films with good sensitivity in the X-ray diagnostic field have recently been developed and are commercially available as GAFCHROMIC XR-QA. There are potential advantages in the use of radiochromic films such as a more comprehensive dosimetry thanks to the adjustable size of the film samples. The purpose of this study was to investigate the feasibility of using radiochromic films for dental CT dose evaluations. Film samples were cut with a width of 5mm and a length of 25 mm (strips), the same size as the Alderson Rando anthropomorphic phantom holes used in this study. Dental CT dose measurements were performed using simultaneously both TLD and radiochromic strips in the same phantom sites. Two equipment types were considered for dental CT examinations: a 16 slice CT and a cone beam CT. Organ equivalent doses were then obtained averaging the measurements from the sites of the same organ and effective doses were calculated using ICRP 103 weighting factors. The entire procedure was repeated four times for each CT in order to compare also the repeatability of the two dosimeter types. A linear correlation was found between the absorbed dose evaluated with radiochromic films and with TLD, with slopes of 0.930 and 0.944 (correlation r>0.99). The maximum difference between the two dosimeter's measurements was 25%, whereas the average difference was 7%. The measurement repeatability was comparable for the two dosimeters at cumulative doses above 15 mGy (estimated uncertainty at 1 sigma level of about 5%), whereas below this threshold radiochromic films show a greater dispersion of data, of about 10% at 1 sigma level. We obtained, using respectively Gafchromic and TLD measurements, effective dose values of 107 µSv and 117 µSv (i.e. difference of 8.6%) for the cone beam CT and of 523 µSv and 562 µSv (i.e. difference of 7%) for the multislice CT. This study demonstrates the feasibility of radiochromic films for dental CT dosimetry, pointing out a good agreement with the results obtained using TLD, with potential advantages and the chance of a more extensive dose investigation.

Reconstruction of facial morphology from laser scanned data. Part I: reliability of the technique.

OBJECTIVES: The aim of this study was to evaluate the effects of scanning parameters on the precision of the data acquired using a facial laser scanner and to assess the reliability of automatic model recording in humans. METHODS: Data were acquired using a laser scanner (Cyberware 3030RGB); analysis and measurements were performed with Rapid Form 2004 software. A mannequin and six volunteers were scanned to investigate the effects of environmental conditions, positioning, head orientation, and software procedures. Precision and accuracy of the data were evaluated comparing six linear measures calculated on scanned data with those obtained directly. Two sessions with different head inclination were performed. The reliability of repeated scans was also assessed measuring the distance between the surfaces reconstructed from two separate scans of the same subject, at 12 anatomical points, in 5 subjects, during two sessions using a different head inclination. Differences were analysed using paired t-tests or analysis of variance (ANOVA). RESULTS: The accuracy of scanning was +/-0.65 mm. The development of a specific protocol resulted in a mean scanning error of 1-1.2 mm and a recording error of 0.3-0.4 mm on repeated scans of human subjects. CONCLUSIONS: This study indicates that scanning of the human face may be hampered by errors and artefacts, mainly due to movements. While the effect of trembling and involuntary movements during the exam may be minimized using faster scanning devices, comparative observation over time may be affected by unreal differences due to the uncertainty of facial expression. The overall error is, however, in the range useful for most clinical studies.

Transverse maxillary distraction with a bone-anchored appliance: dento-periodontal effects and clinical and radiological results.

In 29 adult patients presenting with maxillary deficiency, a bone-anchored palatal distractor (Surgi-Tec NV, Brugge, Belgium) was applied after osteotomy of the anterolateral walls of the maxillary sinuses, midpalatal suture, and, eventually, separation of the pterygomaxillary sutures. Expansion proceeded at a rate of 0.33-0.66 mm per day and the device was retained for 4-6 months for consolidation. Active orthodontic therapy was started after 8-10 weeks. The increment of arch width and the perimeter were evaluated using dental casts. Tooth thermal sensitivity and the periodontal side effects of treatment were monitored clinically after distraction, at device removal, and after 1 year. Bone healing was also investigated during the procedure using conventional radiological techniques. This experience confirms that transverse maxillary distraction is an effective technique in adult patients, leading to the formation of new bone. There were no noticeable intraoperative complications, but postsurgical periodontal side effects were documented. The procedure offers advantages over traditional teeth-borne appliances in terms of rapidity of treatment and the absence of mechanical forces acting on the teeth. Further evaluation is required to assess the long-term stability and periodontal consequences of this technique.

The WEBD project: a research of new methodologies for a distant-learning 3D system prototype.

OBJECTIVES: To create and to spread a new interactive multimedia instrument, based upon virtual reality technologies, that allows both the running simulation of machines and equipment and the reproduction via Web of complex three-dimensional (3D) anatomical models such as the skull. METHODS: There were two main aspects of the project, one of design engineering and the other biomedical engineering, for the creation of "artificial" and anatomical objects. The former were made with 3D Studio Max R4 by Autodesk, San Rafael, CA, while the latter were created starting from real bones scanned with a CT system or a surface scanner and elaborated with different programs (3D Studio Max R4, Scenebuilder by Viewpoint, New York, NY and Spinfire by Actify, San Francisco, CA). The 3D models were to be integrated into web modules and had to respect file limits while preserving a sufficient definition. Two systems of evaluation were used, a questionnaire on a selected sample and an external evaluation by a different university. RESULTS: The Viewpoint format offers the best interactivity and size reduction (up to 96% from the original 3D model). The created modules included production of radiological images, rapid prototyping, and anatomy. The complete "3D Distant Learning Prototype" is available at www.webd.etsii.upm.es. CONCLUSIONS: The software currently available permits the construction of interactive modules. The verification on the selected sample and the evaluation by the University of Naples show that the structure is well organized and that the integration of the 3D models meets the requirements.

Early loading of sandblasted and acid-etched (SLA) implants: a prospective split-mouth comparative study.

Sandblasted and acid-etched (SLA) implants were recently introduced to reduce the healing period between surgery and prosthesis. In this split-mouth study, SLA implants were compared to titanium plasma-sprayed (TPS) implants under loaded conditions one year after placement in 32 healthy patients, with comparable bilateral edentulous sites and no discrepancies in the opposing dentition. The surgical procedure was performed by the same operator and was identical at 68 SLA (test) and 68 TPS (control) sites. Tapping was never performed and primary stability was always achieved. Abutment connection was carried out at 35 Ncm 6 weeks postsurgery for test sites and 12 weeks for the controls, by the same dentist blind to the type of surface of the implant. In 4 of the 68 test sites the implant rotated slightly, patients reported minor pain and connection was not completed. Provisional restoration was fabricated and a new tightening was performed after six weeks. Similar gold-ceramic restorations were cemented on the same type of solid abutments on both sites. No implant was lost. Clinical measures and radiographic changes were recorded by the same operator, blind to the type of surface of the implant, 1 year post surgery. No significant differences were found with respect to presence of plaque (24% vs. 27%), bleeding on probing (24% vs. 31%), mean pocket depth (3.3 mm vs. 2.9 mm) or mean marginal bone loss (0.65 mm vs. 0.77 mm). The results suggest that SLA implants are suitable for early loading at 6 weeks. Limited implant spinning may occasionally be found but, if properly handled, it produces no detrimental effect on the clinical outcome.

Unilateral fibroadipose degeneration of the masticatory muscles.

A unique case of fatty replacement of the masticatory muscles, causing progressive limitation of mouth opening, is presented. Both CT and MRI revealed an almost total substitution of the masticatory muscles with fatty tissue, confirmed by the histopathology at surgery. Myotomy of masseter and internal pterygoid muscles and coronoidotomy improved his symptoms. There is no known cause of fibroadipose replacement of muscle fibres.

[Check of compliance with quality criteria for diagnostic radiographic images in quality control]. / Verifica del rispetto dei livelli diagnostici di riferimento nella radiodiagnostica nell'ambito dei controlli programmati della qualità.

PURPOSE: To devise and implement a programme of measurements to assess the entrance surface dose for a standard-sized patient and to check the compliance with diagnostic reference levels. MATERIAL AND METHODS: Dose evaluation was performed on 40 radiographic instruments. The exposure parameters were collected for the main radiographic procedures (chest, skull, spine, pelvis, abdomen) each performed with instrument on a standard-sized patient. The output of each X-ray tube at 70, 80, 90, 100, 110 and 120 kV was measured with a solid state detector during quality controls. Beam quality and geometric characteristics of the equipment were also determined. The entrance surface dose for a standard patient was assessed for each procedure carried out with the 40 instruments, thus obtaining a total of 155 radiographic techniques. Finally, the method was validated by comparing the values obtained with the solid state and an ionization chamber for X-ray beam detector. RESULTS: The comparison between the solid state detector and the ionisation chamber demonstrated a good agreement. Results show that reference diagnostic levels are respected in most examinations (147/155) even if exposure values do not always comply with those indicated by European guidelines. The measurement programme seems to be applicable in hospital practice where the large number of radiographics instruments and procedures requires the acquisition and processing of a large number of data. CONCLUSIONS: The evaluation of patient dose during quality control is feasible and allows a first check of compliance with reference levels in order to identify which procedures can be optimised by means of more specific measurements and assessments.

Dimensions and volumes of the orbit and orbital fat in posttraumatic enophthalmos.

OBJECTIVES: To estimate from 2D and 3D-CT the anatomical defects that are most likely to be responsible for posttraumatic enophthalmos. MATERIALS AND METHODS: The morphology and dimensions of the orbit and of fat content were investigated in 25 patients 6-12 months after treatment for complex orbital fractures by image analysis and volumetric estimation from 2D and 3D-CT. RESULTS: The shape of orbit was very often changed from conical to more rounded due to enlargement of the posterior segment. The retrobulbar fat appeared fragmented and dislocated posteriorly. No changes were observed in the structural appearance or radiodensity of either the orbital fat or muscles. There was reduced sagittal eye projection, increased width of the orbital rim, downward dislocation of the posteromedial orbital floor, and increased volume in the posttraumatic orbits which was significantly different (P < 0.05). Enophthalmos was correlated with orbital volume and height of the retrobulbar portion of the orbit. The volume of fat did not correlate with enophthalmos. CONCLUSIONS: Posttraumatic enophthalmos appears to be more commonly related to failure in correcting the orbital volume and in reducing the outward dislocation of the posterior orbital floor and not to changes in the fat content.

[Tridimensional ultrasonography. First clinical experience with dedicated devices and review of the literature]. / Ecotomografia tridimensionale. Prime esperienze cliniche con apparecchiatura dedicata e revisione della letteratura.

PURPOSE: We report our preliminary clinical experience with three-dimensional ultrasound (3D US) in abdominal and small parts imaging, comparing the yield of 3D versus 2D US and through a literature review. MATERIAL AND METHODS: We used a Tomtec Echo-Scan 3.1 connected to a Philips P 700 unit with a 3.5 MHz convex probe and to a Toshiba SSA-340 A (equipped with power Doppler) with a 3.5 MHz convex and a 7.5 MHz linear probes. The system consists of: a) a workstation (166 MHz Intel Pentium, 128 Mbytes RAM, 520 Mbytes hard disk, 1.3 Gbyte Magneto-Optical drive); b) a spatial location system (3D Freehand Scanning) whose sensor, attached to the probe, provides spatial coordinates for each US scan in an electromagnetic field created by a transmitter; the software can thus correctly stack 2D US images to make 3D reconstructions of anatomical structures. The technical steps are: 1) setting; 2) image acquisition; 3) image processing and 3D rendering using surface or volume modes; 4) image archiving. 2D US was performed on 50 subjects, namely 20 volunteers and 30 patients with different pathologic conditions and 3D reconstructions were obtained from the best US images. We evaluated which anatomical structures and pathologic conditions are best suited for 3D rendering. RESULTS: The best 3D images were obtained from anatomical structures and pathologic conditions with a liquid content (i.e., bladder and gallbladder; cysts), or those adjacent to them (i.e., uterus and prostate). Major limitations were encountered in the assessment of the parenchyma of liver, kidneys, pancreas, thyroid, testis and breast, due to intrinsic texture low contrast, while intraparenchymal liquid structures (i.e., vessels, urinary cavities) and structures surrounded by liquid (i.e., hydrocele, ascites) were better demonstrated. DISCUSSION: The system permits accurate spatial location, and therefore stacking, of each US scan; this provides good-quality 3D images with fewer artifacts. The system can be connected to any existing US unit and to many kinds of probes. Incorrect processing or rendering may worsen 3D image quality and thus anatomical reconstructions; other drawbacks may come from difficult stacking of reconstructed images or limited field of view. Our personal experience and the review of 3D US literature indicate that the system may be used for the following clinical applications: anatomical assessment of lesions for minimally invasive treatment; targeting areas of interest and adjacent structures during radiotherapy; lesion volume studies during therapy; 3D vascular mapping with power Doppler; 3D reconstructions by intraluminal approach; real-time 3D scanning for US guidance during minimally invasive procedures. CONCLUSIONS: Our preliminary experience suggests that technological progress will soon lead to a widespread use of 3D US and its applications.

Radiological aspects of osteosarcoma of the jaws.

OBJECTIVES: To categorize the radiological presentation of osteosarcoma of the jaws. METHODS: Conventional radiographs and CT scans of nine patients with histologically proven osteosarcoma were reviewed. RESULTS: Five patients were men and four women, aged between 20 and 51; four lesions were in the maxilla and five in the mandible. Three radiological presentations of osteosarcoma of the jaw were identified. The first was radiolucent, characterized by a total absence of bone formation within the tumour. The second had a mottled appearance with small areas of amorphous ossification separated by non-ossified tumour tissue. The third, with lamellar ossification, was typically characterized by bony plates irradiating from a focus like a 'sunburst'. CONCLUSION: Radiological diagnosis of osteosarcoma of the jaw can be difficult because of its variable appearance. CT is particularly useful.

[Panoramic radiography using an intraoral tube. Method, anatomy, radiography and dosimetry]. / La radiografia panoramica con sorgente endorale. Tecnica, anatomia radiografica e dosimetria.

BACKGROUND: There are two techniques giving a panoramic view of the dental arch: orthopantomography and intraoral tube panoramic radiography. The last one is not very well known because images, with a characteristic and variable deformity if compared with orthopantomography are not useful for routinary use in dentistry. The poor radiographic and pathologic anatomy knowledge of intraoral tube panoramic radiography, and the slight improvements brought to the method particularly in order to reduce the dose, partly depend on the scant attention given to the method by investigators, and partly on the dyshomogeneous anatomic sites enlargement and overlapping with consequent deformity of all of them. With intraoral tube panoramic radiography, X-ray exposition is emitted using a miniaturized cylindrical source placed inside the oral cavity and the radiographic film is in contact with the skin of the face. Based on the orientation of the collimator and the inclination of the tube major axis in the oral cavity, a central technique (exposition of either superior or inferior dental arch) and a lateral technique (simultaneous exposition of the two hemiarches of the same side) are recognized. The aim of this study is to give a significative contribution to maxillo-facial characteristic appearance and dosimetry knowledge in intraoral tube panoramic radiography. METHODS: It consists of: a) a "laboratory" part concerning the evaluation of the enlargement, deformation and visibility of different structures, obtained by positioning about fifty different markers in different maxillary and mandibular anatomic sites, and b) an in vivo dosimetry part obtained with intraoral and extraoral termoluminiscent dosimeters. An original dispositive allowed the right positioning of the film and its adherence to the screen. Deformity characteristics are analitically described and discussed in relation with the different sites. RESULTS AND CONCLUSIONS: The use of intensifying screens allowed a good reduction of dose, (mean absorbed doses ranging from 25 microGy in the intraoral sites to 1936 microGy in the extraoral sites) without reducing the image quality thanks to the device performed "ad hoc".

The use of replicate resin models in the treatment of maxillary sinus augmentation patients.

The elevation of the floor of the maxillary sinus is becoming a routine surgical procedure to develop the site for dental implants. This delicate procedure is best performed with diagnostics of the highest magnitude. To this point, computer tomographic scans provide valuable information, especially when defining the location and extension of septae transversing the sinus. Additional useful information is provided by a replicate resin model that is constructed from a magneto-optical disk compatible with a personal computer. The image data is then converted to a DOS format. Bone structures of interest are thresholded in each slice based on single-pixel gray levels. Object profiles with linear interpolation and their elaboration generate the three-dimensional surface of the object. Finally, the physical resin model is fabricated.

Hyperplasia of the mandibular coronoid process: long-term follow-up after coronoidotomy.

The aim of this study was to evaluate long-term results of treatment by intraoral coronoidotomy and prolonged physiotherapy in five patients with mandibular coronoid process hyperplasia. Five consecutive cases of coronoid process hyperplasia were studied (two unilateral and three bilateral) at the Department of Maxillo-facial Surgery of the University of Turin during the period 1985-1990. All patients were treated by intraoral coronoidotomy and given physiotherapy from the third postoperative day. This continued for an entire year. A clinical and radiological follow-up (average 39.4 months), in three cases over a 5-year period, was completed. Three months after the operation, all patients had achieved satisfactory improvement in mandibular interincisal opening. The mean value for mouth opening at the end of follow-up was 42 mm. Radiographic follow-up showed the presence of a coronoid process almost the size of the original, apparently united with the mandibular ascending ramus, with moderate dislocation and inclination posterior to the body of the zygomatic bone. The results of this study indicate that treatment of coronoid process hyperplasia by intraoral coronoidotomy, when combined with prolonged postoperative physiotherapy, gives satisfactory and stable long-term results in the correction of coronoid-malar interference.

[Niobium filtration in dental radiology. Effects on image quality and on dosage]. / Filtrazione al niobio nella radiologia dentale. Effetti sulla qualità dell'immagine e sulla dose.

UNLABELLED: The necessity of reducing the radiation dose to the patient in diagnostic radiology according to the ALARA guideline established by the ICRP has stimulated the research on additional filtration systems capable of removing the low-energy photons increasing the dose and worsening image quality. Very few literature studies deal with the effects of niobium filtration on image quality in dental radiography with the use of modulation transfer function (MTF) and square wave response function (SWRF). Only one study has considered those effects measuring dose absorption in an anthropomorphic phantom. THE AIMS OF OUR STUDY WERE: 1) to study the effects of a 30 microns additional niobium filter on image quality using the SWRF; 2) to compare the doses absorbed in vivo during a complete radiographic survey of the mouth, both with and without niobium filtration. Qualitative studies led us to conclude that niobium filtration does not significantly worsen radiographic image quality. The following doses were measured in the exposures with niobium filtration: 1678 microGy to 6000 microGy (intraoral doses) and 75 microGy to 3643 microGy (skin doses). The comparison with the doses measured during the exposures made with conventional filtration indicates that dose reduction is not significantly advantageous relative to risk reduction. In conclusion, additional niobium filtration is not advisable in dental radiology, also because of the filter cost and of the increased wear of the unit.

["Empty cysts" of the jaws]. / Le "cisti vuote" dei mascellari.

BACKGROUND: The extensive use of orthopantomography contributed to the occasional discovery of the so called empty cysts (EC) also defined as traumatic or hemorrhagic, which are benign mainly asymptomatic lesions. There are different opinions on empty cysts (even on the proper term to define them) particularly regarding their epidemiology, etiopathology, and clinical and radiological aspect. The purpose of this study is to compare the literature and personal experience and to underline the peculiar aspects not only from a semantic point of view, but also from a more elaborate perspective. MATERIALS AND METHODS: Forty-five osteolytic lesions, which can be considered as empty cysts, taken out of a group of 30,000 patients in a period of 5 years have been examined retrospectively. Radiologic documentation included: orthopantomography, occlusal radiographs, intraoral periapical radiographs, intraoral tube panoramic radiographs and TC in 4 cases. Several parameters among which: trauma, symptoms, location, dimension and the radiological aspect of the lesion were taken into account. RESULTS: The authors concluded: trauma in 4 cases, location of 44 out of 45 empty cysts in the mandible, 67% of which distal to canines; displacement of adjacent teeth in four cases, without root resorbtion. The major axis of empty cysts varied from a minimum of 18 to a maximum of 80 mm. The morphology was oval or round, 37 cysts were monolocular, 8 were plurilocular. In 17 cases the authors noticed a reduction and a displacement of the corticals, but never discovered a pathological fracture. During the observed period an increase in growth of lesions was not found in the follow-up of 14 out of 44 patients. CONCLUSIONS: The personal data were compared to those of the literature where the authors found a larger incidence of patients with symptoms and a history of trauma and cementofibrousdysplasia. The authors suggested that the real incidence of empty cysts is higher than that of the literature. On the basis of personal experience empty cysts are very stable. Therefore, it is questionable if oral surgery should be avoided when radiological picture is certain.

Parosteal osteosarcoma of the maxilla.

We describe the case of a 47-year-old female who presented with a small nodule in the buccal sulcus in the left maxillary incisor region. Clinical and radiographic examination revealed a small sclerotic neoplasm with a short pedicle. Histopathological examination confirmed a diagnosis of parosteal osteosarcoma. The contribution of CT to the diagnosis and management is discussed.

[The validation of stereolithographic anatomical replicas: the authors' own experience and a review of the literature]. / Convalida delle repliche anatomiche stereolitografiche: esperienza personale e revisione della letteratura.

The visual three-dimensional (3D) reconstruction of CT findings has been used since the Seventies to design and plan complex surgical procedures. The availability of such models and the development of computer science have permitted, since the mid-Eighties, the medical use of rapid prototyping for anatomical modelling. We studied the technical steps of CT data processing for rapid prototyping and the dimensional and structural accuracy of replicas of skeletal components relative to the originals. A dried mandible and an arthrotic hip joint were compared with their stereolithographic replicas using the measurements made on CT images. The 3D graphic models were processed with a commercially available software and replicated with an SLA 250 stereolithographer (3D System Inc, Valencia CA, USA). Satisfactory morphologic agreement was found between the original and its replica. The mandibular replica exhibited dimensional errors ranging 0 to 4.03%, z-axis shortening and an increase in gonial angle, but with a reliable reproduction of details. The hip replica exhibited dimensional errors ranging .2% to 8.53%; it appeared to be less affected than the mandibular replica by geometrical distortion but it was less accurate in the reproduction of cancellous bone and arthrosis. The accuracy of the solid replicas depends, in the different manufacturing steps, on several factors, namely: during data acquisition, the accuracy and suitability of original data, depending in turn on equipment and examination parameters--especially the algorithm, acquisition time, gantry tilt and slice thickness; image thresholding and manipulation procedures during graphic model creation; data transfer, creation of the necessary supports and replica finishing during manufacturing; residual polymerization affected by environmental agents and preservation conditions during maintenance.

[The role of the traditional radiological methods in conservative therapy and endodontics]. / Ruolo delle metodiche radiologiche tradizionali in terapia conservativa ed endodontica.

The traditional radiographic examinations used in restorative dentistry and endodontics are: intraoral radiograph performed in the beta-wing or the paralleling technique, the partial extraoral radiograph (rotational narrow beam), the panoramic radiography and the periapical radiographs with the bisecting technique which is particularly suitable for visualization of the apex. Radiology is a valuable diagnostic means to evaluate the extension of primary caries, to identify secondary and interproximal initial decays and if required let the therapist measure the biological width. Several factors influence the radiographic interpretation of caries: cervical burnout, mach band effect, internal and external resorption, restorative materials for fillings and sub-bases, abrasions and/or erosions. Radiology allows the diagnosis of developmental and acquired abnormalities of the teeth which can have an influence on the treatment itself. Examples are: variations in the shape of the crown and root, dens in dente, enamel hypoplasia, dentinogenesis imperfecta. Radiograms are of major importance in the evaluation of restorative dentistry results: precision of the margins, congruous contact points, fractures. Moreover, it provides the endodontic procedures with useful diagnostic data and permits the measurements during the treatment, supplying the immediate and long term checks too.

[Radiological considerations of malpractice in dentistry]. / Considerazioni radiologiche sulla "malpractice" in odontoiatria.

Several branches of competence are needed to evaluate malpractice in dentistry: first a complete case history, secondly careful clinical observation and finally a correct procedure of radiographic documentation. This latter is able to prove existence of the treatment and its evolution, moreover it shows the bone, the dental components underneath the surface and the treatment becomes appraisable by different observers. In restorative dentistry, radiological findings allow us to demonstrate overcontoured restorations in approximal sites and, if necessary, identify the biological width. In endodontics the insufficient filling or the overfilling of the root channel can be demonstrated along with the material used for the filling and the presence of fractured instruments inside the channel. In prosthodontics, on the other hand, the quality of the abutments, fractured roots and/or prosthesis, symptoms of inadequate charge on the bone and overcontours with the subsequent periodontal damage can be seen. In orthodontics one can assess the appearance of infrabone pockets, reabsorptions and horizontal recessions. In extractive surgery it is again possible to identify through radiographic documentation small root fragments in the maxillary sinus (possible sinusitis associated) and maxillary fractures as a consequence of extractions. In the field of implantology, damage to noble structures due to inadequate case planning can be highlighted.