Guided Zygomatic Implantology for Oral Cancer Rehabilitation: A Case Report.

Oral rehabilitation after maxillary oncological resection is challenging. This case report presents the rehabilitation of a 65-year-old Caucasian male adenoid cystic carcinoma patient using a myo-cutaneous thigh flap, zygomatic implant placement, and an immediate fixed provisional prosthesis made with computer-aided technologies. The patient presented complaints of asymptomatic enlarged swelling of 5-mm on the right hard hemi-palate. There was an oro-antral communication deriving from a previous local excision. Preoperative radiographs showed the involvement of the right maxilla, maxillary sinus, and nose with a suspect involvement of the maxillary division of the trigeminal nerve. Treatment was planned through a fully digital workflow. A partial maxillectomy was performed endoscopically, and maxilla was reconstructed using an anterolateral thigh free flap. Two zygomatic implants were inserted simultaneously. A provisional fix full-arch prosthesis was manufactured preoperatively through a fully digital workflow and was placed in the operating room. Following post-operative radiotherapy, the patient received a final hybrid prosthesis. During the follow-up period of two years, the patient reported good function, aesthetics, and significant enhancement in quality of life. According to the results of this case, the protocol represented can be a promising alternative for oral cancer patients with large defects, and can lead to an improved quality of life.

Zygomatic Implant Insertion in MRONJ: A Case Report with a Follow-Up of 3 Years.

The oral rehabilitation of MRONJ patients represents a challenging situation. Conventional dental implant insertion is not indicated because of the risk of creating a new necrotic area. This case study describes the oral rehabilitation of a 78-year-old female patient, who developed an osteonecrotic lesion in the fourth year of bisphosphonate treatment. The patient underwent a series of surgeries, including resection of the necrotic tissue on the right maxillary region and removal of conventional implants. The patient had a large maxillary defect, and no other treatment modalities such as conventional prosthetic appliances and traditional dental implant insertions were applicable. The patient had a very poor quality of life and as a rehabilitation option, two zygomatic implant insertions were planned and performed as an anchorage for maxillary fixed prosthesis. Radiographic and clinical examination after three years of follow-up indicated that healing was achieved, and healthy tissues formed around zygomatic implants. The patient did not suffer from any additional necrotic tissues or other complications in the oral cavity. According to the results of this case report, zygomatic implantation after resective surgery might be considered as a promising alternative for MRONJ patients with large defects when other treatment alternatives fail or are not applicable.

A Plaster Cast Contact Scan Method to Assess the Accuracy of Full-Arch Computer-Aided Implant Surgery.

PURPOSE: The aim of this study was accuracy assessment of placed implants in full-arch cases using specific software and hardware to perform static computer-assisted implantology and immediately loaded prostheses. The degree of deviation existing between planned and achieved implants was carried out by a new noninvasive measurement procedure of the implant position performed on stone casts. MATERIALS AND METHODS: Fourteen stone casts retrieved from 14 full-arch fully guided implant treatments were selected to perform the study. Each cast, manufactured for the surgical treatment by using a specific laboratory kit, was obtained from the respective surgical guide. A sleeve for each implant was embedded into the guide, which helped the examiners to manufacture a stone cast per guide containing the implant analogs, which was used to recover the final position of the planned implants. A total sample of 60 implants were assessed. The postoperative casts, poured to produce the immediate prostheses, were then processed by a contact (or tactile) scanner, and the generated standard tessellation language (STL) files were overlapped (best-fit alignment) using engineering software that revealed all the measured discrepancies. In terms of accuracy, differences relating to arch, assessed bone quality, implant length, and drill length (prolongation short or long) were reported. RESULTS: The use of a noninvasive tactile scanner revealed mean entry point horizontal deviations of 0.30 mm (SD: 0.39 mm), mean entry point vertical deviations of 0.20 mm (SD: 0.25 mm), mean apical horizontal deviations of 0.50 mm (SD: 0.73 mm), and mean apical vertical deviations of 0.24 mm (SD: 0.28 mm). The frontal and lateral angular deviations were investigated, and corresponding mean values of 1.99 degrees (SD: 2.30 degrees) and 1.80 degrees (SD: 2.44 degrees) were detected. CONCLUSION: The reported results demonstrate that the contact tactile scan is a viable and biologic way to assess implant deviations.

Artificial Intelligence: A New Diagnostic Software in Dentistry: A Preliminary Performance Diagnostic Study.

BACKGROUND: Artificial intelligence (AI) has taken hold in public health because more and more people are looking to make a diagnosis using technology that allows them to work faster and more accurately, reducing costs and the number of medical errors. METHODS: In the present study, 120 panoramic X-rays (OPGs) were randomly selected from the Department of Oral and Maxillofacial Sciences of Sapienza University of Rome, Italy. The OPGs were acquired and analyzed using Apox, which takes a panoramic X-rayand automatically returns the dental formula, the presence of dental implants, prosthetic crowns, fillings and root remnants. A descriptive analysis was performed presenting the categorical variables as absolute and relative frequencies. RESULTS: In total, the number of true positive (TP) values was 2.195 (19.06%); true negative (TN), 8.908 (77.34%); false positive (FP), 132 (1.15%); and false negative (FN), 283 (2.46%). The overall sensitivity was 0.89, while the overall specificity was 0.98. CONCLUSIONS: The present study shows the latest achievements in dentistry, analyzing the application and credibility of a new diagnostic method to improve the work of dentists and the patients' care.

Use of Intraoral Scanners for Full Dental Arches: Could Different Strategies or Overlapping Software Affect Accuracy?

OBJECTIVES: The use of digital devices is strongly influencing the dental rehabilitation workflow both for single-crown rehabilitation and for full-arch prosthetic treatments. METHODS: In this study, trueness was analyzed by overlapping the scan dataset made with Medit I-500 (by using two different tips and two different scan strategies) with the scan dataset made with lab scanning, and the values of the (90°-10°)/2 method were reported. Precision was evaluated by using the same values of trueness coming from the intra-group overlapping (scan dataset made with an IOS overlapped and compared to each other). Moreover, two different software programs of overlapping were used to calculate accuracy values. RESULTS: The mean difference of trueness was 26.61 ± 5.07 µm with the suggested strategy of intraoral scanning and using a new design of the tip, 37.99 ± 4.94 µm with the suggested strategy of intraoral scanning and using the old design of the tip, and 51.22 ± 6.57 µm with a new strategy of intraoral scanning and using the old design of the tip. The mean difference of precision was 23.57 ± 5.77 µm with the suggested strategy of intraoral scanning and using a new design of the tip, 38.34 ± 11.39 µm with the suggested strategy of intraoral scanning and using the old design of the tip, and 46.93 ± 7.15 µm with a new strategy of intraoral scanning and using the old design of the tip. No difference was found in the trueness and precision data extracted using the two different programs of superimposition Geomagic Control X and Medit Compare. CONCLUSIONS: The outcomes of this study showed that the latest version of I-Medit 500 with the use of a new tip seems to be promising in terms of accuracy when a full arch needs to be scanned. Moreover, Medit Compare, which is an application of Medit IOS software, can be used to calculate IOS accuracy.

A 4 mm-Long Implant Rehabilitation in the Posterior Maxilla with Dynamic Navigation Technology: A Case Report after a Three-Years Post-Loading Follow-Up.

The use of short (<8 mm long) and ultra-short (<6 mm long) implants allows the prosthetic rehabilitation of the posterior ridges of the jaws avoiding reconstructive procedures. Nevertheless, this approach requires vast experience to ensure the primary stability of the fixture in a correct position. Computer-aided implantology (CAI) achieves better results than the free-hand one in terms of placement accuracy, reducing the surgical risks and the operative timings. Dynamic navigation (DN) allows the surgeon to track the position and movements of the drill in real-time on the CT imaging data set. It is more versatile than the computed static system, enabling the operator to change the guidance coordinates according to the intra-operative feedbacks. A mono-edentulous upper right first molar site was rehabilitated with a four mm-long implant to avoid reconstructive techniques, drastically rejected by the patients. The case was managed within a DN protocol considering the minimal available bone and the prosthetic demands. The phases of this procedure were strictly documented up to a 3-year follow-up. No intra-operative problems occurred, and adequate primary stability of the implant was obtained. The prosthetic loading was carried out within only six weeks without any complications. No variation of the baseline clinical scenario as evidenced clinically and radiographically at the end of follow-up. No similar cases are reported in the literature.

Digital Approach for the Rehabilitation of the Edentulous Maxilla with Pterygoid and Standard Implants: The Static and Dynamic Computer-Aided Protocols.

A full-arch rehabilitation of the edentulous upper jaw without grafting procedures exploits the residual alveolar or the basal bone, with the necessity of long implants placed with a particular orientation. The precision in planning and placing the fixtures is fundamental to avoid clinical problems and to allow an acceptable connection with the prosthesis. The computer-aided implantology resulted in more accuracy than the traditional one, with a high standard of correspondence between the virtual project and the real outcome. This paper reports about the two different digital protocols, static and dynamic, as support to implant-borne prosthetic rehabilitation of edentulous maxillae. Two pterygoid and two/four anterior standard implants were seated in both cases by two different operators, without flap raising, and immediately loaded. This approach avoided the posterior cantilever by-passing the maxillary sinus and was adequately planned and realized without any surgical or prosthetic error. The two digital flow-charts were described step by step, underlining each other's advantages and drawbacks compared to a free-hand approach.

Dynamic Navigation for Zygomatic Implants: A Case Report about a Protocol with Intraoral Anchored Reference Tool and an Up-To-Date Review of the Available Protocols.

Dynamic Navigation is a computer-aided technology that allows the surgeon to track the grip instruments while preparing the implant site in real time based on radiological anatomy and accurate pre-operative planning. The support of this technology to the zygoma implant placement aims to reduce the risks and the errors associated with this complex surgical and prosthetic treatment. Various navigation systems are available to clinicians currently, distinguished by handling, reliability, and the associated economic and biological benefits and disadvantages. The present paper reports on the different protocols of dynamic navigations following a standard workflow in correlation with zygomatic implant supported rehabilitations and describes a case of maxillary atrophy successfully resolved with this technology. An innovative and minimally invasive dynamic navigation system, with the use of an intraoral anchored trust marker plate and a patient reference tool, has been adopted to support the accurate insertion of four zygomatic implants, which rapidly resolved maxillary atrophy from a 75-year-old male system. This approach provided an optimal implant placement accuracy reducing surgical invasiveness.

Precision of Dynamic Navigation to Perform Endodontic Ultraconservative Access Cavities: A Preliminary In Vitro Analysis.

INTRODUCTION: Ultraconservative access cavities (UCACs) have been proposed to reduce crown weakening, but there is no consensus about their design and size and about their advantages and disadvantages, which are also related to how differently they are performed. The purpose of the present study was to evaluate the possible use of a novel Dynamic Navigation System (DNS) in planning and executing UCACs and its precision in vitro, compared with a manual approach (MA) without any guide. METHODS: Twenty radiopaque, artificial teeth replicas were randomly divided into 2 identical groups and scanned using cone-beam computed tomography. In the first group (MA) MB1 canal orifice was reached, starting from the central part of the molar occlusal surface, using a micro endodontic bur. In the second group, DNS allowed to plan and execute a more direct, straight-line truss access. After cavity preparation, teeth were scanned again, and cone-beam computed tomography images were compared. Data were statistically analyzed with analysis of variance test. RESULTS: Significant differences (P < .05) were found in the tested parameters between the 2 groups. The DNS group was significantly more precise, showing smaller mean values in the angulation (4.8°) and in the maximum distance from the ideal position (0.34 mm), when compared with MA group (mean values, 21.2° and 0.88 mm, respectively). CONCLUSIONS: Hence, we may conclude that the use of DNS increased the benefits of UCACs by minimizing the potential risk of iatrogenic weakening of critical portions of the crown and reducing negative influences to shaping procedures.

Factors Influencing the Soft Tissue Changes Around Single Laser Microtextured Implants-Abutments in the Anterior Maxilla: A 5-Year Retrospective Study.

PURPOSE: The aim of this study was to evaluate the possible factors that influenced the periimplant soft tissue changes around single implants-abutments with laser-microtextured surface (LMS) in the esthetic zone. MATERIALS AND METHODS: Thirty-nine units, formed by implant-abutment with LMS were studied. Variables possibly associated with the periimplant soft tissue changes were obtained from clinical measurements (plaque [present/absent], periimplant biotype [thin/thick], and probing depth); intrasurgical measurements (vertical height in millimeters of the keratinized gingiva in the vestibular part of the implant site vestibular keratinized gingiva [VKG], implant vestibular crestal exposition, vestibular crestal level, and vestibular bone width); cast models (implant position [buccal/palatal], implant abutments angle); periapical radiographs (distance from the contact point to the interproximal bone crest of the adjacent tooth [CP-BC], distance from the contact point to the implant platform [CP-P], distance from the contact point to the first bone to implant contact [CP-IB]); and digital clinical photographs. Fisher exact test was used to determine the influence of each factor on the papilla level and on the facial marginal mucosal level. RESULTS: The papillae level at the implant sites was significantly associated with the distance from the contact point to the alveolar bone crest, whereas no association was found with other variables. Periimplant biotype, differences in the VKG, CP-BC, and CP-IB were found associated with the different facial marginal mucosal level groups. CONCLUSIONS: This study showed that the papilla level at single-tooth implants-abutments with LMS in the anterior maxilla was mainly influenced by the interproximal bone crest level of the adjacent tooth, whereas the marginal mucosal level was affected by periimplant biotype, facial bone crest level, and crestal implant exposition.

Clinical, Radiographic, and Histologic Evaluation of Maxillary Sinus Lift Procedure Using a Highly Purified Xenogenic Graft (Laddec(®)).

OBJECTIVES: The aim of this study was to evaluate the clinical, radiographic and histologic results when a highly purified xenogenic bone (Laddec(®)) was used as grafting material in maxillary sinuses. MATERIAL AND METHODS: In fifteen patients requiring unilateral maxillary sinus augmentation, the grafting procedure was performed with Laddec(®). Forty-two implants were installed after a 6 month healing period. The height of the augmented sinus was measured radiographically immediately after augmentation and postoperatively up to 36 months. At the time of implant placement, a bone core was harvested in each patient for histological examination. RESULTS: The cumulative implant survival rate was 97.6%. The original height was 3.65 (SD 0.7) mm and the augmented sinus height was 13.8 (SD 1.4) mm after the surgery. The reduced height of grafted xenogenic material (RDL) at the implant insertion was 0.83 (SD 0.38) mm, and at the final postoperative visit was 0.91 (SD 0.25) mm, showing no significant correlation with the follow-up periods by Spearman's test (P = 0.118). In addition, no significant difference in the RDL was observed according to the site of implantation (P = 0.682). The mean implant marginal bone loss was 0.38 (SD 0.24) mm. Histological analysis showed the bone cores were composed of 64.72 (SD 3.44)% newly formed bone, 17.41 (SD 2.02)% connective tissue, 16.93 (SD 2.83)% residual graft particles, and 0.94 (SD 0.11)% inflammatory cells. CONCLUSIONS: According to our data, the highly purified xenogenic bone (Laddec(®)), used as graft material in the sinus lift procedure, may create adequate bone volume, and appropriate osseointegration of dental implants.

Accuracy of positioning of implants inserted using a mucosa-supported stereolithographic surgical guide in the edentulous maxilla and mandible.

PURPOSE: The aim of this study was to evaluate the accuracy of implants inserted using a mucosa-supported stereolithographic surgical guide and to determine the influence of surgical management of the guide (fixed or unfixed), arch (maxilla or mandible), and smoking habit (normal or hyperplastic mucosa) on accuracy. MATERIALS AND METHODS: In completely edentulous subjects, preoperative computed tomography (CT) was performed, and the images were used to plan implant positions. After the implants were placed, CT was performed again, and the presurgical and postoperative images were compared. With computer software, the jaw contours from the two CT scans were matched and the deviations between the planned and actual implant positions were evaluated. Surgical technique, arch, and smoking habit were examined as independent variables, and their influence on accuracy was evaluated with a t test. RESULTS: Twenty-eight surgical guides (225 implants) were included in this study. Deviations between planned and actual positions were seen in the global coronal (mean±SD: 1.68±0.6 mm), global apical (2.19 ± 0.83 mm), and angular (4.67 ± 2.68 degrees) dimensions. Fixation of surgical guides (fixed: 4.09 degrees; not fixed: 5.62 degrees) and use of the guide in the maxilla (4.36 degrees; mandible: 5.46 degrees) resulted in statistically significantly less angular deviation (ie, better accuracy). Nonsmoking patients showed statistically significantly better accuracy in global coronal (nonsmokers: 1.54 mm; smokers: 1.83 mm) and global apical (nonsmokers: 2.08 mm; smokers: 2.27 mm) deviations. CONCLUSION: The greater supporting surface of the maxilla and fixation of the surgical guide improved the accuracy of the guides. The reduced mucosa thickness in nonsmokers decreased global coronal and global apical deviation.

How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study.

PURPOSE: Recently, cone beam computed tomography (CBCT) has become widely used for oral and maxillofacial imaging. Twenty dry mandibles were CBCT and conventional multislice CT scanned to evaluate if there is a statistically significant difference between the bone density values they produce, defined as gray density values, and to determine any correlation between them. MATERIALS AND METHODS: Using software and a radiographic template, the CT and CBCT scan images were overlapped, and two data sets were created, each one giving the respective gray values (voxel value [VV] or Hounsfield unit [HU]) of the same area with the same spatial coordinates. For the statistical analysis, t-test, Pearson's correlation, and Pearson's r were used. RESULTS: The differences between the CBCT (VV) and CT (HU) gray density values were statistically significant (p ≤ .05), whereas the Pearson's correlation coefficients and Pearson's r-values demonstrated a statistically significant linear correlation between VV and HU gray density values. CONCLUSION: The lower radiation dose and reduced costs of CBCT make this a useful substitute for CT; however, this study has shown that, in order to more accurately define the bone density with CBCT, a conversion ratio needs to be applied to the VV.

Platelet Rich Fibrin (P.R.F.) in reconstructive surgery of atrophied maxillary bones: clinical and histological evaluations.

INTRODUCTION: Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin) was tested for the first time in France by Dr. Choukroun. Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss), as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss) was used as reconstructive material. MATERIALS AND METHODS: 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a) Bio-Oss and b) amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times. RESULTS: 72 sinus lifts were performed with subsequent implants insertions.We want to underline how the histological results proved that the samples collected after 106 days (Early protocol) with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized. CONCLUSIONS: The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading.