Odontogenic Maxillary Sinusopathies: a Radiological Classification.

Purpose: Before implant surgery, a preoperative radiological evaluation is recommended for recognizing maxillary inflammatory conditions. In order to avoid a failure of the dental procedure and prevent medical-legal consequences, it is necessary to treat patients suffering of maxillary sinus pathologies. The classification proposed in our study aims to standardize the reference values for mucosal thickening and to verify their association with the odontogenic or disventilatory causes of sinus pathology. Methods: The maximum mucosal thickness was measured at the level of the maxillary sinus floor: mucosal thickness was present when greater than 1 mm and was classified according to its extension within the sinus cavity. Results: Imaging data of 270 adult patients were included, performed for dental diagnosis and treatment planning, and they were divided into four main classes: Class I (85 pt.), mucosal thickness lesser than 2 mm, not pathological. Class II A (52 pt.), mucosal thickness between 2 and 5 mm, localized to the maxillary sinus floor: it is still considered non-pathological, and a "wait-and-see" approach is recommended. Class II B (46 pt.), mucosal thickness greater than 5 mm but localized at sinus floor: pathological mucosa with odontogenic etiology, requiring dental treatment. Class III A (39 pt.), mucosa thicker than 5 mm and concentric, most likely due to sinus ventilation disfunction: it requires maxillary antrostomy. Class III B (30 pt.), sinonasal manifestations such as nasal polyposis, retention cysts, mucocele, dental foreign body: pathological mucosa to be treated with ESS. Class IV (12 pt.), oroantral fistula: nasal endoscopic or oral approach. Conclusions: Our classification intends to suggest the better therapeutic option, in case of sinus pathology, according to the entity and pathogenesis of the mucosal thickening, in order to reduce complication and failure rate of dental surgery.

Osteotome-Induced Blood Clot and Subsequent Bone Formation with the Use of Collagen Sponge for Integration of Single Dental Implants into the Atrophied Posterior Maxilla: A Retrospective Follow-Up of 36 Implants after 5 to 13 years.

BACKGROUND: Atrophy of the posterior maxilla as a consequence of tooth loss and sinus pneumatization is a frequent condition encountered in the clinical practice. Prosthetic rehabilitation with implants in these patients often requires some kind of bone regeneration procedure to increase the bone volume. AIM: The aim of the present retrospective study is to analyze the survival and success rates of a series of implants placed in the atrophic posterior maxilla with a transcrestal osteotome procedure, without placing a bone grafting material. MATERIALS AND METHODS: From 2006 to 2014, 36 dental implants (Neoss Ltd., Harrogate, UK) were inserted in 36 patients with at least 4 mm of bone below the maxillary sinus using transcrestal osteotome sinus floor elevation and placement of collagen sponge below the sinus membrane. ISQ measurements were made after implant placement and at abutment surgery after 4 to 6 months. The vertical bone height (VBH) was evaluated in intraoral radiographs taken prior to surgery and in radiographs from annual check-up appointments 5 to 13 years after implant placement. In addition, marginal bone loss (MBL) was evaluated. RESULTS: One implant was lost after four years of prosthetic loading. The remaining 35 implants showed no complications and were loaded with single crowns after 4-6 months of healing. All 35 implants showed clinical success after 8.5 ± 2.8 years of prosthetic loading (from 5 to 13 years). The vertical bone height was 5.9 ± 1.4 mm at surgery, 9.7 ± 1.1 mm at second surgery after 4-6 months, and 8.3 ± 1.8 at the follow-up at 8.5 ± 2.8 years (from 5 to 13 years). The implant stability registered was 73.2 ± 6.2 ISQ at the surgery and 75.8 ± 3.9 at the second surgery after 4-6 months. CONCLUSIONS: The present long-term follow-up study showed that the crestal approach for sinus floor bone augmentation without additional bone grafting results in predicable bone formation and high implant survival. The osteotome technique is a valid alternative to the more invasive lateral window technique in single cases with a minimum of 4 mm of VBH below the maxillary sinus.

Phenytoin and gingival mucosa: A molecular investigation.

Several distinct classes of drugs, such as anticonvulsants, immunosuppressants, and calcium channel blockers, caused gingival overgrowth. One of the main drugs associated with the gingival overgrowth is the anti-epileptic such as phenytoin, which affects gingival tissues by altering extracellular matrix metabolism. In our study, we evaluate the effect of phenytoin, a drug whose active substance is phenytoin, on gingival fibroblasts of healthy volunteers. Gene expression of 29 genes was investigated in gingival fibroblasts' cell culture treated with phenytoin compared with untreated cells. Among the studied genes, only 13 genes (CXCL5, CXCL10, CCR1, CCR3, CCR5, CCR6, IL-1A, IL-1B, IL-5, IL-7, IL-6R, BMP-2, and TNFSF-10) were statistically significant. All but one gene resulted downregulated after 24 h of treatment with phenytoin. BPM2 was the only, although weakly, up-expressed gene. Probably, we have not highlighted overexpression of the other inflammatory molecules because the study was performed on healthy people. Many studies show that phenytoin induces the overexpression of these cytokines but, probably, in our study, the drug does not have the same effect because we used gingival fibroblasts of healthy people.

The use of a new chemical device based on silver and cationic surfactants as a new approach for daily oral hygiene: A preliminary study on a group of periodontal patients.

The aim of this study was to evaluate the abatement power of oral microbial loading of a new gel formulation based on the complex silver-2-mercaptobenzoate, chlorhexidine digluconate and didecyldimethylammonium chloride (named ADC) through polymerase chain reaction (PCR). The study sample consists of a group of 20 patients with chronic periodontal disease. Patients were over 25 years of age and did not undergo surgical or non-surgical periodontal treatment in the previous 6 months. The study sample was allotted into two groups of 10 patients each, homogeneous by age and sex. The test group received a bottle containing ADC gel, while the control group received an identical one containing placebo, similar to ADC in consistence, colour, taste and odour. Sub-gingival samples of four sites, one in each quadrant, of greatest probing depth in each patient were used. Microbiological analyses were performed at baseline and at day 15. Paired t test was performed to detect statistical significant reduction in total bacterial loading and oral pathogens in the study groups. The analysis showed a statistically significant reduction in the total bacterial loading evaluated pre- and post-treatment (P = 0.029) in the study groups. In the control group, the decrease in total bacterial loading was not significant (P = 0.279). Clinically, ADC gel does not have any side effects and discomfort such as pain, burning, tingling sensation or numbness and produces no adverse reactions in time. Our study aimed to evaluate the efficacy of a new chemical formulation with antibacterial properties to use for daily oral hygiene with a preliminary study. Our results showed a statistically significant reduction in total bacterial loading after treatment, but the limitations of our study do not allow us to demonstrate the clinical efficacy of the ADC gel.

Skeletal changes after rapid maxillary expansion in children with obstructive sleep apnea evaluated by low-dose multi-slice computed tomography.

OBJECTIVE: The objective of this study was to evaluate the skeletal effects of rapid maxillary expansion (RME) therapy performed using teeth as anchors, in obstructive sleep apnea (OSA) children, by low-dose computed tomography (CT) of the midpalatal suture opening, maxillary base width, nasal cavities width, first molar angulation and, unlike most studies in the literature, on the pterygoid processes distance. METHODS: Fourteen children (mean age 8.68 years) with OSA presenting a malocclusion characterized by upper-jaw contraction had 16-Multislice CT (MSCT) scans taken before (T0) and after (T1) RME. All exams were performed using a rigid protocol to ensure reproducibility of image collection over time, with a 16-row MSCT scanner equipped with a Dentascan reconstruction program. Scanning parameters were as follows: scout view in the anteroposterior (AP) and laterolateral (LL); 1.25-mm slice thickness with 0.6-mm collimation from the dentoalveolar and basal areas of the maxilla up to the nasal cavity, parallel to the palatal plane; 80 kV, 100 mA with an 11.25-mm table speed/rotation, rotation time 0.6 s. Matrix size was 512 × 512. RESULTS: Opening of the midpalatal suture was demonstrated in all cases. The results showed statistically significant T0 to T1 increments in all treated cases and clear imaging findings. CONCLUSION: Use of three-dimensional (3D)-CT for follow-up studies requires a very rigid protocol to maintain reproducible positions in the scanner over time. The images confirm the real remodeling of craniofacial structure. However, to be valid such an imaging approach needs great attention to reproducibility of anatomic images over time. The changes in volume of the UA, even with a rigid protocol, cannot be affirmed with 3D-CT. There is a need to improve the definition of markers using this imaging approach when performing longitudinal studies; currently this issue is unresolved.

Histological and Histomorphometrical Analysis on a Loaded Implant With Platform-Switching and Conical Connection: A Case Report.

The association of Morse taper implant-abutment design with the use of a smaller abutment diameter (platform switching) may improve dental implant success rate and prevent peri-implant bone loss. The aim of the present study was to histologically and histomorphometrically evaluate the behavior of peri-implant tissues around an implant with a conical connection associated with platform switching. A platform-switched Morse-cone connection implant was inserted in the left posterior mandible of a 61-year-old patient. The implant was inserted at the level of the alveolar crest. After 11 months from placement and 6 months of loading, the implant was retrieved for psychological reasons and processed for histological evaluation. The retrieved implant was wholly surrounded by bone tissue, except for a small area in the apical portion. At higher magnification, in the coronal portion of the implant, it was possible to observe bone directly at the implant platform level. No resorption of the coronal bone was present, except for 0.2 mm on the vestibular aspect. Crestally, bone remodeling with areas of newly formed bone was detected; the bone-implant contact was 73.9%. Apposition of bone was detected even upon the platform. Peri-implant crestal bone preservation can be achieved with the combination of Morse taper conical internal implant-abutment connection with the use of a smaller abutment diameter (platform-switching).

Effects of Repeated Screw Tightening on Implant Abutment Interfaces in Terms of Bacterial and Yeast Leakage in Vitro: One-Time Abutment Versus the Multiscrewing Technique.

Screw loosening can damage the interfaces of implant components, resulting in susceptibility to contamination of the internal parts by microorganisms. The aim of this study was to investigate the impact of abutment screw retightening on the leakage of two different types of bacteria, Streptococcus sanguinis and Fusobacterium nucleatum, and of the yeast Candida albicans. Two types of implant-abutment systems with tube-in-tube interfaces were tested. Groups A and B each used a different type of system that consisted of 20 different pieces that were assembled according to the manufacturer's torque recommendations; four samples in each group were closed just one time, four samples three times, four samples five times, four samples seven times, and four samples nine times. The implants of groups A and B were contaminated with 0.1 µL of microbial solution just before being assembled for the last time to minimize the possibility of contamination. Results showed a direct correlation between the number of colony-forming units grown in the plates and the closing/opening cycles of the implant-abutment systems. Within the limitations of this study, the results indicate the possibility that repeated closing/opening cycles of the implant-abutment unit may influence bacterial/yeast leakage, most likely as a consequence of decreased precision of the coupling between the abutment and the internal part of the dental implant. These findings suggest that a one-time abutment technique may avoid microbiologic leakage in cases of implant-abutment systems with tube-in-tube interfaces.

Expression of Pattern Recognition Receptors in Epithelial Cells Around Clinically Healthy Implants and Healthy Teeth.

BACKGROUND: Gingival epithelial cells have a pivotal role in the recognition of microorganisms and damage-associated molecular pattern molecules and in the regulation of the immune response. The investigation of the behavior of Toll-like receptors (TLRs) and nucleotide oligomerization domain (NOD) like receptors (NLRs) around a healthy implant may help to address the first step of periimplantitis pathogenesis. PURPOSE: To investigate by quantitative real-time polymerase chain reaction, the mRNA expressions of TLR2, TLR3, TLR4, TLR5, TLR6, TLR9, NOD1, NOD2, and NLRP3 from gingival epithelial cells of the sulcus around healthy implants and around healthy teeth. MATERIALS AND METHODS: Two types of implant-abutment systems with tube-in-tube interface were tested. After 6 months of implant restoration, gingival epithelial cells were obtained from the gingival sulcus around the implants and around the adjacent teeth of 10 patients. RESULTS: Our results did not reach statistical significance among the mRNA expressions of TLR2, TLR3, TLR4, TLR5, TLR6, TLR9, NOD1, NOD2, and NLRP3 in epithelial cells around the implant versus around natural teeth. CONCLUSION: This study shows that the implant-abutment systems tested did not induce an immune response by the surrounding epithelial cells at 6 months since their positioning, as well as in the adjacent clincally healthy teeth.

Comparative evaluation of osseointegrated dental implants based on platform-switching concept: influence of diameter, length, thread shape, and in-bone positioning depth on stress-based performance.

This study aimed to investigate the influence of implant design (in terms of diameter, length, and thread shape), in-bone positioning depth, and bone posthealing crestal morphology on load transfer mechanisms of osseointegrated dental implants based on platform-switching concept. In order to perform an effective multiparametric comparative analysis, 11 implants different in dimensions and in thread features were analyzed by a linearly elastic 3-dimensional finite element approach, under a static load. Implant models were integrated with the detailed model of a maxillary premolar bone segment. Different implant in-bone positioning levels were modeled, considering also different posthealing crestal bone morphologies. Bone overloading risk was quantified by introducing proper local stress measures, highlighting that implant diameter is a more effective design parameter than the implant length, as well as that thread shape and thread details can significantly affect stresses at peri-implant bone, especially for short implants. Numerical simulations revealed that the optimal in-bone positioning depth results from the balance of 2 counteracting effects: cratering phenomena and bone apposition induced by platform-switching configuration. Proposed results contribute to identify the mutual influence of a number of factors affecting the bone-implant loading transfer mechanisms, furnishing useful insights and indications for choosing and/or designing threaded osseointegrated implants.

Microbiological evaluation of bacterial and mycotic seal in implant systems with different implant-abutment interfaces and closing torque values.

OBJECTIVE: The aim of this study was to evaluate the possible leakage of 3 species of bacteria (Streptococcus sanguinis, Fusobacterium nucleatum, and Actinomyces odontolyticus) and of Candida albicans and Candida glabrata in osseointegrated implants with different implant-abutment interface (IAI) geometry. MATERIALS AND METHODS: Two groups of implants, (1) implant-abutment unit with a tube-in-tube interface and (2) implant-abutment unit with a flat-to-flat interface closed with different torque values, were compared in the study. In the first phase, the implants were assembled and cultured in vitro for 7 days. The implants and abutments were disconnected and samples were taken and cultured. In the second phase, the internal part of each implant was inoculated with 0.1 µL of microbial broth and then connected to the respective abutments. Afterward, medium samples were taken and cultured. RESULTS: The group 1 implants were more resistant to colonization than those of group 2 (P < 0.05). The intragroup difference was significant between the implant-abutment units assembled with the recommended torque values and those with lower torque values (P < 0.01) for both the groups. CONCLUSION: IAI geometry influences both bacterial and yeast colonization inside the implants as well as the torque value used to connect abutments to implants.

Implant-bone load transfer mechanisms in complete-arch prostheses supported by four implants: a three-dimensional finite element approach.

STATEMENT OF PROBLEM: Complete-arch restorations supported by fewer than 5 dental implants can induce unbalanced load transfer and tissue overloading, leading to excessive bone resorption and possible clinical failure. This is primarily affected by the cantilever length, the implant design and positioning, and the morphology and properties of the bone. PURPOSE: The purpose of this study was to compare 2 different restorative techniques for complete-arch rehabilitations supported by 4 implants. The primary purpose was to highlight the possible risks of excessive stress and unbalanced load transfer mechanisms and to identify the main biomechanical factors affecting loading transmission. MATERIAL AND METHODS: Three-dimensional (3D) numerical models of edentulous maxillae and mandibles restored with 2 techniques using 4 implants were generated from computed tomography (CT) images and analyzed with linear elastic finite-element simulations with 3 different static loads. The first technique used 2 vertical mesial implants and 2 tilted distal implants (at a 30 degree angle), and the second used vertical implants that fulfilled platform switching concepts. Bone-muscle interactions and temporomandibular joints were included in the mandibular model. Complete implant osseous integration was assumed and different posthealing crestal bone geometries were modeled. Stress measures (revealing risks of tissue overloading) and a performance index (highlighting the main features of the loading partition mechanisms) were introduced and computed to compare the 2 techniques. RESULTS: Dissimilar load transfer mechanisms of the 2 restorative approaches when applied in mandibular and maxillary models were modeled. Prostheses supported by distally tilted implants exhibited a more effective and uniform loading partition than all vertical implants, except in the simulated maxilla under a frontal load. Tilted distal implants reduced compressive states at distal bone-implant interfaces but, depending on bone morphology and loading type, could induce high tensile stresses at distal crests. Overloading risks on mesial periimplant bone decreased when the efficient preservation of the crestal bone through platform switching strategies was modeled. CONCLUSIONS: Numerical simulations highlighted that the cantilever length, the implant design and positioning, and the bone's mechanical properties and morphology can affect both load transmission mechanisms and bone overloading risks in complete-arch restorations supported by 4 implants. Distally tilted implants induced better loading transmission than vertical implants, although the levels of computed stress were physiologically acceptable in both situations.

Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis.

X-ray micro-tomography (micro-CT) is a miniaturized form of conventional computed axial tomography (CAT) able to investigate small radio-opaque objects at a-few-microns high resolution, in a non-destructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure). Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues.

The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis.

STATEMENT OF PROBLEM: Load transfer mechanisms and possible failure of osseointegrated implants are affected by implant shape, geometrical and mechanical properties of the site of placement, as well as crestal bone resorption. Suitable estimation of such effects allows for correct design of implant features. PURPOSE: The purpose of this study was to analyze the influence of implant diameter and length on stress distribution and to analyze overload risk of clinically evidenced crestal bone loss at the implant neck in mandibular and maxillary molar periimplant regions. MATERIAL AND METHODS: Stress-based performances of 5 commercially available implants (2 ITI, 2 Nobel Biocare, and 1 Ankylos implant; diameters of 3.3 mm to 4.5 mm, bone-implant interface lengths of 7.5 mm to 12 mm) were analyzed by linearly elastic 3-dimensional finite element simulations, under a static load (lateral component: 100 N; vertical intrusive component: 250 N). Numerical models of maxillary and mandibular molar bone segments were generated from computed tomography images, and local stress measures were introduced to allow for the assessment of bone overload risk. Different crestal bone geometries were also modelled. Type II bone quality was approximated, and complete osseous integration was assumed. RESULTS: Maximum stress areas were numerically located at the implant neck, and possible overloading could occur in compression in compact bone (due to lateral components of the occlusal load) and in tension at the interface between cortical and trabecular bone (due to vertical intrusive loading components). Stress values and concentration areas decreased for cortical bone when implant diameter increased, whereas more effective stress distributions for cancellous bone were experienced with increasing implant length. For implants with comparable diameter and length, compressive stress values at cortical bone were reduced when low crestal bone loss was considered. Finally, dissimilar stress-based performances were exhibited for mandibular and maxillary placements, resulting in higher compressive stress in maxillary situations. CONCLUSIONS: Implant designs, crestal bone geometry, and site of placement affect load transmission mechanisms. Due to the low crestal bone resorption documented by clinical evidence, the Ankylos implant based on the platform switching concept and subcrestal positioning demonstrated better stress-based performance and lower risk of bone overload than the other implant systems evaluated.

Unusual evolution of a residual dental cyst: a giant rhinolith.

Rhinoliths are calcareous concretions, consisting mainly of calcium and magnesium carbonates and phosphates. They can vary in size and shape, from small bodies to massive growths, and may invade adjacent structures. A 75-year-old female with a history of purulent discharge, nasal obstruction, and headache was observed in the ENT Department, University of Rome "Tor Vergata". Clinical examination revealed a giant rhinolith completely obstructing the right nasal cavity. Curiously, a dental CT scan showed a bony destruction area related to a residual dental cyst that had migrated superiorly into the maxilla. A transnasal, surgical approach was performed, and the rinolith was completely removed under local anaesthesia. The authors suggest that the giant rhinolith could have an odontogenic origin and that it could be an unusual complication of residual dental cyst.

Paroxysmal positional vertigo as a complication of osteotome sinus floor elevation.

Paroxysmal positional vertigo (PPV) is a high prevalence, vestibular end organ disorder due to the detachment of the utricular otoconia floating in the posterior or lateral semicircular canal. Even though in the majority of cases the etiology of PPV is unknown, it may follow viral infection, vascular disorders and head trauma after different surgical procedures. The aim of this study was to investigate the correlation between PPV and the surgical trauma induced by the vibratory and percussive forces on the upper maxilla during the osteotome sinus floor elevation procedure. We performed a complete otoneurological examination on 146 patients affected by atrophic ridges before and after upper maxilla surgery. Four patients showed a PPV of the posterior semicircular canal controlateral to the implanted side 1 or 2 days after the surgical procedure, which promptly was solved with the Epley re-positioning maneuver. We hypothesize that the surgical trauma, and specifically the pressure exerted by the osteotomes, determines the detachment of the otoliths from the utricular macula while the patient head position, hyper-extended and tilted opposite to the side where the surgeon is working, favors the entry of these free-floating particles in the posterior semicircular canal of the implanted side. Although this disease is rather frequent in the normal population and it is a benign, self-limiting peripheral disorder, it should be considered by the oral surgeon as a possible complication of pre-prosthetic upper maxilla surgery, and the patient should be informed before undergoing surgery.