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Language Medicina oral, patología oral y cirugía bucal. Ed inglesa. 2015. Vol. 20, no. 1
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- Odontogenic myxofibroma: a concise review of the literature with emphasis on the surgical approach(2015) Meleti, Marco; Giovannacci, Ilaria; Corradi, Domenico; Manfredi, Maddalena; Merigo, Elisabetta; Bonanini, Mauro; Vescovi, PaoloPurpose : The aim of this work is to report a review of the literature concerning epidemiology, clinical and radiographic features as well as treatment of odontogenic myxofibroma (MF). Methods : The PubMed database was searched using the following keywords: “odontogenic myxofibroma”, “odontogenic fibromyxoma”, “myxofibroma of the jaw” and “fibromyxoma of the jaw”. Results : Fifteen articles reporting the experience with 24 patients were identified. Male/female ratio was 1:1.4 and the average age was 29.5 years. The most frequent location was the mandible. In 66.7% of the cases the radiographic appearance was a multilocular radiolucency. Swelling was observed in 13 patients (92.86%), varying degrees of pain in 5 (35.71%) and paresthesia in only one patient (7.14%). Six out of 24 patients (26.09%) were treated with radical surgery and 17 (73.91%) with a conservative approach. In two out of 21 cases (9.52%) a recurrence was reported. Conclusions : MF is an extremely rare tumor and no agreement exists on the causes of its development. According to the present review, the choice of treatment should depend on variables such as localization, presence of a primary or of a recurrent lesion, age, general medical conditions and aesthetic needs of the patient
- Morphologic outcome of bimaxillary surgery–An anthropometric appraisal(2015) Raschke, Gregor-Franziskus; Rieger, Ulrich M.; Peisker, Andre; Djedovic, Gabriel; Gomez Dammeier, Marta; Guentsch, Arndt; Schaefer, Oliver; Schultze Mosgau, StefanObjectives: To adequately perform orthognathic surgery procedures, it is from basic interest to understand the morphologic changes caused by orthognathic surgery. Anthropometric analyses of standardized frontal view and profile photographs could help to investigate and understand such changes. Study Design: We present a pre- to postoperative evaluation of orthognathic surgery results based on anthropometric indices described by Farkas and cephalometric measurements. 30 Class III patients undergoing maxillary advancement by Le Fort I Osteotomy and mandibular setback by bilateral sagittal split osteotomy were evaluated. Preoperative as well as three and nine months postoperative lateral cephalograms as well as standardized frontal view and profile photographs were taken. On the photographs 21 anthropometric indices given by Farkas were evaluated. In cephalograms SNA and SNB angle as well as Wits appraisal were investigated. Results: The investigated anthropometric indices showed a significant increase of the vertical height of the upper lip without changing the relation of the upper vermilion to the cutaneous upper lip. The lower vermilion height increased relatively to the cutaneous lower lip without vertical changes in the lower lip. Due to maxillary advancement the upper face height increased meanwhile the lower face height decreased due to mandibular setback. SNA and SNB angle and Wits appraisal showed typical changes related to surgery. Conclusions: The investigated photo-assisted anthropometric measurements presented reproducible results related to bimaxillary surgery.
- A randomized clinical trial compared the effect of intra-alveolar 0.2 % Chlorohexidine bio-adhesive gel versus 0.12% Chlorohexidine rinse in reducing alveolar osteitis following molar teeth extractions(2015) Abu-Mostafa, Nedal; Alqahtani, Abdullah; Abu Hasna, Mohammed; Alhokail, Ahmed; Aladsani, AmmarObjectives: To evaluate socket healing, incidence of acute alveolar ostieitis (AO) and associated pain following single molar tooth extraction in patients who receive intra-alveolar 0.2% chlorhexidine (CHX) gel, and those who rinsed with 0.12 % CHX rinse. Study Design: A prospective randomized clinical trial was conducted on two parallel groups of patients. Group1 (141 patients): Rinsed with 0.12 % CHX rinse from the second postoperative day, two times daily for a week. Group2 (160 patients): Who had direct intra-alveolar application of 0.2% CHX gel and day 3 post-operatively. The socket was evaluated 3 and 7 day postoperatively for the presence of AO by checking probing tenderness in the socket, empty socket, food debris, halitosis and pain assessment by VAS. Results: Forty-eight AO cases were diagnosed out of 301 extractions (15.9%). In Group1, 25 cases were found (17.7%) while 23 cases were found in Group2 (14.4%). The difference was not statistically significant ( p =0.428). Presence of empty socket and food debris in Group1 were higher than in Group2 but the difference was not sta - tistically significant ( p = 0.390 & p = 0.415). Occurrence of halitosis in Group2 was more than Group1, but the difference was not significant ( p = 0.440). Statistical significance was found between AO in extraction done by root separation (29%) and those routinely extracted (12.3 %) ( p =0.001). Conclusions: Postoperative evaluation of molar extraction sockets that received direct intra-alveolar application of 0.2% CHX gel showed insignificant less occurrence of AO when compared with 0.12 % CHX rinse
- Effect of intra-alveolar placement of 0.2% chlorhexidine bioadhesive gel on the incidence of alveolar osteitis following the extraction of mandibular third molars. A double-blind randomized clinical trial(2015) Rubio Palau, Josep; García Linares, Jordi; Hueto Madrid, Juan Antonio; González Lagunas, Javier; Raspall Martín, Guillermo; Mareque Bueno, JavierAlveolar osteitis (AO) is a common complication after third molar surgery. One of the most studied agents in its prevention is chlorhexidine (CHX), which has proved to be effective. Objectives: The aim of this randomized double-blind clinical trial was to evaluate the efficacy of 0.2% bioadhesive chlorhexidine gel placed intra-alveolar in the prevention of AO after the extraction of mandibular third molars and to analyze the impact of risk factors such as smoking and oral contraceptives in the development of AO. Study Design: The study was a randomized, double-blind, clinical trial performed in the Ambulatory Surgery Unit of Hospital Vall d’Hebron and was approved by the Ethics Committee. A total of 160 patients randomly received 0.2% bioadhesive gel (80 patients) or bioadhesive placebo (80 patients). Results: 0.2% bioadhesive chlorhexidine gel applied in the alveolus after third molar extraction reduced the incidence of dry socket by 22% compared to placebo with differences that were not statistically significant. Smoking and the use of oral contraceptives were not related to higher incidence of dry socket. Female patients and the difficulty of the surgery were associated with a higher incidence of AO with statistically significant differences. 0.2% bioadhesive chlorhexidine gel did not produce any of the side effects related to chlorhexidine rinses. Conclusions: A 22% reduction of the incidence of alveolar osteitis with the application of 0.2% bioadhesive chlorhexidine gel compared to placebo with differences that were not statistically significant was found in this clinical trial. The lack of adverse reactions and complications related to chlorhexidine gel supports its clinical use specially in simple extractions and adds some advantages compared to the rinses in terms of duration of the treatment and reduction of staining and taste disturbance-
- Evaluation of osteoblastic activity in extraction sockets treated with platelet-rich fibrin(2015) Baslarli, Ozgur; Tumer, Celal; Ugur, Omer; Vatankulu, BetulObjective: The aim of this study was to determine whether the use of platelet rich fibrin (PRF) improved the healing of extraction sockets. Study Design: A total of 20 patients with bilateral soft tissue impacted mandibular third molars were included in this study. The left and right third molars were extracted during the same session. Subsequently, the PRF membrane was randomly administered to one of the extraction sockets, whereas the contralateral sockets were left without treatment. On postoperative 30. and 90. days, panoramic images and bone scintigrams were taken to evaluate the bone healing between PRF-treated and non-PRF-treated sockets. Also, periodontal evaluation was performed in the same control sessions. Dependent group t test for paired samples was used for statistical analysis. Results: The average increase in technetium-99m methylene diphosphonate uptake as an indication of enhanced bone healing did not differ significantly between PRF-treated and non-PRF- treated sockets 30 and 90 days postoperatively. Radioopacity that can show the bone healing on panoramic images were measured by Image J programme and they did not differ significantly. Also periodontal values did not differ significantly. Conclusions: PRF might not lead to enhanced bone healing in impacted mandibular third molar extraction sockets 30 and 90 days ater surgery. It is thought that PRF has the potential characteristics of an autologous fibrin matrix and can accelerate the healing. To better understand the effects of PRF on healing, further research is warranted with larger sample sizes
- Granular cell tumor of the oral cavity: a case series including a case of metachronous occurrence in the tongue and the lung(2015) Loo, Sander van de; Thunnissen, Erik; Postmus, Pieter E.; Van der Waal, IsaäcThe granular cell tumor (GCT) is a rare, benign tumor that most commonly occurs in the oral cavity, particularly in the anterior part of the tongue. In this study the experience with 16 patients with a GCT observed in a single Institution will be discussed. Although no radicality has been obtained in most cases, recurrences are rare. In one patient, a recurrence was noted four years after excision of the primary. In the same patient a pulmonary lesion occurred five years after excision of the recurrence in the oral cavity, most likely representing an example of metachronous occurrence and not a distant metastasis. Since recurrences and metachronous lesions are rare, as are distant metastases, routine follow-up does not seem warranted in patients treated for a granular cell tumor of the oral cavity.
- Odontogenic tumors: a collaborative study of 218 cases diagnosed over 12 years and comprehensive review of the literature(2015) Sekerci, Ahmet Ercan; Nazlim, Sinan; Etoz, Meryem; Denız, Kemal; Yasa, YasinObjectives: The objective of this study was to analyze the frequency and distribution of odontogenic tumors (OTs) in the Cappadocia region of Turkey, and to compare the findings with those reported in the literature. Study Design: The records of the Oral and Maxillofacial Surgery and Pathology Departments at Erciyes University, with histologic diagnosis of odontogenic tumors (based on the World Health Organization classification, 2005), over a 12-year period, were analyzed. The relative frequency of different types of tumors was also analyzed and compared with the literature. Results: OTs in the present study constituted 2.74% of all the 7,942 registered biopsies. A total of 218 cases of OTs were collected and reviewed. Of these, (94.04%) were benign and (5.96%) were malignant. The mandible was the most commonly affected anatomic location, with 170 cases (77.9%). Ameloblastoma with a predilection for the posterior mandible was the most frequent odontogenic tumor (30.28%), followed by keratocystic odontogenic tumor (19.5%), odontoma (13.4%), and odontogenic myxoma (8.5%). Conclusions: OTs are rare neoplasms and appear to show geographic variations in the world. In Cappadocia, Turkey, they are more common in the mandible, with ameloblastoma followed by keratocystic odontogenic tumors with the incidences observed in the present study being similar to those of previous studies from Asia and Africa, and in contrast to those reported from American countries.
- Optimization of buffer solutions to analyze inflammatory cytokines in gingival crevicular fluid by multiplex flow cytometry(2015) Ríos Lugo, María Judith; Martín, Conchita; Alarcón, Jose Antonio; Esquifino Parras, Ana Isabel; Barbieri, Germán; Solano, Patricia; Sanz Alonso, MarianoObjective: the aim of this study was to test two buffer solutions in order to attain a reliable and reproducible analysis of inflammatory cytokines (IL-1β, IL-6, TNF-α, OPG, OPN and OC), in gingival crevicular fluid (GCF) by flow cytometry. Material and Methods: GCF samples from healthy volunteers were collected with perio-paper strips and diluted either in phosphate buffered saline (PBS) or Tris-HCl buffer, with and without protease inhibitors (PI). Cytokine immunoassays were carried out by flow cytometry (Luminex Xmap 200 ) generating standard curves. Results: standards curves generated with the use of phosphate-buffered saline (PBS) demonstrated best adjustment for cytokines IL-1ß, IL-6 and TNF- α levels, when using Tris-HCl ( p <0.05). Conclusions: The use of PBS buffer with the addition of PI provided reliable measurements of inflammatory biomarkers in GCF samples of healthy volunteers.
- Transition from glass to digital slide microscopy in the teaching of oral pathology in a Brazilian dental school(2015) Fonseca, Felipe Paiva; Santos Silva, Alan Roger; Lopes, Márcio Ajudarte; Almeida, Oslei Paes de; Vargas, Pablo AgustínObjectives: Several medical and dental schools have described their experience in the transition from conventional to digital microscopy in the teaching of general pathology and histology disciplines; however, this transitional process has scarcely been reported in the teaching of oral pathology. Therefore, the objective of the current study is to report the transition from conventional glass slide to virtual microscopy in oral pathology teaching, a unique experience in Latin America. Study Design: An Aperio ScanScope® scanner was used to digitalize histological slides used in practical lectures of oral pathology. The challenges and benefits observed by the group of Professors from the Piracicaba Dental School (Brazil) are described and a questionnaire to evaluate the students’ compliance to this new methodology was applied. Results: An improvement in the classes was described by the Professors who mainly dealt with questions related to pathological changes instead of technical problems; also, a higher interaction with the students was described. The simplicity of the software used and the high quality of the virtual slides, requiring a smaller time to identify microscopic structures, were considered important for a better teaching process. Conclusions: Virtual microscopy used to teach oral pathology represents a useful educational methodology, with an excellent compliance of the dental students.
- Mechanical behavior of provisional implant prosthetic abutments(2015) Agustín Panadero, Rubén; Serra Pastor, Blanca; Roig Vanaclocha, Ana; Román Rodríguez, Juan Luis; Fons Font, AntonioIntroduction: Implant-supported prostheses have to overcome a major difficulty presented by the morphology and esthetics of peri-implant tissues in the anterior sector. Diverse therapeutic techniques are used for managing the mucosa adjacent to the implant and the most noteworthy is immediate/deferred fixed provisionalization. Objectives: In vitro testing of strength and deformation of implant prosthetic abutments made from different materials (Titanium/PEEK/methacrylate). Material and Methods: Forty Sweden&Martina ® implant prosthetic abutments (n=40) were divided into five groups: Group MP: methacrylate provisional abutments with machined titanium base; Group PP: Polyether ether ketone (PEEK) provisional abutments; Group TP: titanium provisional abutments; Group TAD: titanium anti- rotational definitive abutments; Group TRD: titanium rotational definitive abutments. Their mechanical behavior under static loading was analyzed. Samples were examined under a microscope to determine the type of fracture produced. Results and Conclusions: Definitive anti-rotational titanium abutments and definitive rotational titanium abutments achieved the best mean compression strength, while PEEK resin provisional abutments obtained the lowest. The group that showed the greatest elastic deformation was the group of titanium provisional abutments.
- The clinical significance of CDK1 expression in oral squamous cell carcinoma(2015) Chen, Xin; Zhang, Feng-He; Chen, Qiao-Er; Wang, Yuan-Yin; Wang, Yin-Long; He, Ia-cai; Zhou, JianObjectives: To evaluate the clinical significance of cyclin-dependent kinase 1 (CDK 1 ) in 77 oral squamous cell carcinomas (OSCC) using immunohistochemical methods. Study Design: Immunohistochemical expression of CDK 1 was compared with various clinicopathological features in 77 OSCC and 60 controlled epithelia adjacent to the tumours. In addition, correlation of CDK 1 expression and prognostic and the 5-year accumulative survival rate of OSCC were investigated. Results: The CDK 1 protein was expressed in 52 cases of 77 tumor tissues (67.5%), compared with 21 cases of 60 controlled (35.0%). The expression of CDK 1 was significantly correlated with the histological grade of OSCC ( P <0.05). The CDK 1 protein was over-expressed in recurrent tumors or in those with lymph node metastasis. Statistical analysis showed a significant reduction in the 5-year accumulative survival rate in CDK 1 positive cases compared with CDK 1 negative cases ( P <0.05). Namely, the CDK 1 positive patients had poor prognosis. Conclusions: The expression of CDK 1 might serve as malignant degree and prognostic markers for the survival of OSCC
- In vitro preliminary study of osteoblast response to surface roughness of titanium discs and topical application of melatonin(2015) Solá Ruiz, María Fernanda; Pérez Martínez, Carolina; Martín de Llano, José Javier; Carda Batalla, María del Carmen; Labaig Rueda, CarlosObjectives: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application. Study Design: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: Group I: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM). Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software and SEM. Results: Group II presented the roughest discs, while the least rough were Group III. Cell adhesion was greatest in Group II. The addition of melatonin improved cell proliferation. Conclusions: 1. Surface treatments (dual acid etching, calcium phosphate impaction) increase surface roughness in comparison with machined titanium. 2. Greater surface roughness tends to favor cell adhesion after 24-hour cell culture. 3. The addition of melatonin tends to favor osteoblast proliferation.
- Mammary Analogue Secretory Carcinoma (MASC) of salivary gland in four Mexican patients(2015) Serrano Arévalo, Mónica L.; Mosqueda Taylor, Adalberto; Domínguez Malagón, Hugo; Michal, MichalThe Clinco-pathological, immunohistochemical and molecular findings of four cases of Mammary Analogue Secretory Carcinoma (MASC) of salivary glands found in Mexico are described. The cases were extracted from 253 salivary gland tumors from a single institution in Mexico City. The 85 candidates for initial selection were: low grade mucoepidermoid carcinoma (MEC) (N=70 ), acinic cell cancinoma (AciCC) (N=14), papillary cystadenocarcinoma (N=1), and adenocarcinoma NOS (N=0). Tumors with some histological features consistent with MASC (N= 17, 6.7%) were studied by immunohistochemistry for mammaglobin, STAT5, and S-100 protein and four cases were positive (1.5%), thus the diagnosis of MASC was established, and these were submitted for molecular studies for ETV6-NTRK3 . Fusion gene was demonstrated in three cases, two had been erroneously diagnosed as poorly granulated AciCC, and one as low grade MEC with microcystic pattern. Female gender predominated (3:1); one occurred in the parotid, two in minor salivary glands and one in the submaxillary gland; infiltrating borders, atypical mitosis and lymph node metastases were seen in the parotideal tumor. Two patients with major salivary gland tumors are alive and well at 10 and 20 months respectively, the two patients with minor salivary gland tumors are lost. It can be concluded that is important to think in MASC in poorly granulated AciCC and low grade MEC with microcystic pattern. Immunohistochemisty studies confirm the diagnosis, preferentially supported by molecular studies. MASC may follow aggressive behavior or transform into a high grade neoplasm.
- Differential expression of Cyclin D1 in keratin-producing odontogenic cysts(2015) Vera-Sirera, Beatriz; Forner Navarro, Leopoldo; Vera Sempere, Francisco JoséObjetives: The aim of the present study was to analyze the expression levels of Cyclin D1 (CCD1), a nuclear protein that plays a crucial role in cell cycle progression, in a series of keratin-producing odontogenic cysts. Study Design: A total of 58 keratin-producing odontogenic cysts, diagnosed over ten years and classified according to the WHO 2005 criteria, were immunohistochemically analyzed in terms of CCD1 expression, which was quantified in the basal, suprabasal and intermediate/superficial epithelial compartments. The extent of immunostaining was measured as a proportion of total epithelial thickness. Quantified immunohistochemical data were correlated with clinicopathological features and clinical recurrence. Results:Keratin-producing odontogenic cysts were classified as 6 syndromic keratocystic odontogenic tumors (S-KCOT), 40 sporadic or non-syndromic KCOT (NS-KCOT) and 12 orthokeratinized odontogenic cysts (OOC). Immunohistochemically, CCD1 staining was evident predominantly in the parabasal region of all cystic lesions, but among-lesion differences were apparent, showing a clear expansion of parabasal compartment especially in the S-KCOT, followed to a lesser extent in the NS-KCOT, and being much more reduced in the OOC, which had the greatest average epithelial thickness. Conclusions: The differential expression of CCD1 noted in the present study suggests that dysregulation of cell cycle progression from G1 to the S phase contributes to the different aggressiveness of these lesions. However, CCD1 expression levels did not predict NS-KCOT recurrence, which is likely influenced by factors unrelated to lesion biology
- Diagnostic accuracy of cone-beam CT compared with panoramic images in predicting retromolar canal during extraction of impacted mandibular third molars(2015) Sisman, Yildiray; Sekerci, Ahmet Ercan; Payveren Arıkan, Mehtap; Sahman, HalilObjectives: The clinical significance of the existence of a retromolar canal and of its neurovascular content is not yet clear.The aim of the present study was to assess the visibility, diameter and course of the mandibular retromolarcanal (MRC) using cone beam computed tomography (CBCT) scan -had been taken for pre-operative radiographic evaluation of impacted mandibular third molars- compared to panoramic radiographs. Study Design: Subjects eligible for study enrollment were those who underwent preoperative CBCT scan for the extraction of impactedmandibular third molars were determined to be extremely close to the mandibular canal on panoramic radiographs. Radiographs were screened for the presence and course of retromolar canals, and linear measurements. Results: 947hemimandibles in 632 patients were examined.A total of 253 MRCs (144 left, 109 right) were detected with CBCT images (26.7%). Only 29 of these canals were also seen on the corresponding panoramic radiographs. Most MRCs had a vertical course (type VI, 28.46%), followed by slightly curved (type I, 26.09%). The visibility of the MRC on the OPGs, according to the increase in the diameter, was not statistically significant for both sides ( p >.05).Statistically difference were found for the width at the point of origin from the mandibular canal ( p : .037), the mean distance from the MRC to the second molar ( p : .042) and height of MRC when compared the gender. Conclusions: The findings suggest that the MRC isn’t a rare anatomical structure. This study therefore clearly establishes the incidence and importance of the MRC. The detection of the presence of the MRC using CBCT may be crucial for extraction of mandibular third molars
- Pfeiffer syndrome: clinical and genetic findings in five Brazilian families(2015) Martelli Júnior, Hercílio; Aquino, Sibele Nascimento de; Machado, Renato Assis; Leão, Letícia Lima; Della Coletta, Ricardo; Burle Aguiar, Marcos JoséPfeiffer syndrome (PS) is mainly characterized by craniosysnostosis, midface hypoplasia, great toes with partial syndactyly of the digits and broad and medially deviated thumbs. It is caused by allelic mutations in the fibroblast growth factor receptor 1 and 2 (FGFR1 and 2) genes. This study describes the clinical and genetic features of five Brazilian families affected by PS. All patients exhibited the classical phenotypes related to PS. The genetic analysis was able to detect the mutations Cys278Phe, Cys342Arg, and Val359Leu in three of these families. Two mutations were de novo, with one familial. We identified pathogenic mutations in four PS cases in five Brazilian families by PCR sequencing of FGFR1 exon 5 and FGFR2 exons 5, 8, 10, 11, 15, and 16. The clinical and genetic aspects of these families confirm that this syndrome can be clinically variable, with different mutations in the FGFR2 responsible for PS.
- Atomic force microscopy visualization of injuries in Enterococcus faecalis surface caused by Er,Cr:YSGG and diode lasers(2015) López Jiménez, Lidia; Arnabat Domínguez, Josep; Viñas Ciordia, Miquel; Vinuesa Aumedes, TeresaAim: To visualize by Atomic Force Microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser. Material and Methods: Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by Atomic Force Microscopy (AFM) and its surface roughness determined. Results: AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several cell lysis signs were easily visualized. Surface roughness clearly increase after the treatment with Er,Cr:YSGG at 2W of power, while the other treatments gave similar values of surface roughness. The effect of lasers on bacterial surfaces visualized by AFM revealed drastic alterations. Conclusions: AFM is a good tool to evaluate surface injuries after laser treatment; and could constitute a measure of antimicrobial effect that can complete data obtained by determination of microbial viability.
- Influence of bone parameters on peri-implant bone strain distribution in the posterior mandible(2015) Sugiura, Tsutomu; Yamamoto, Kazuhiko; Kawakami, Masayoshi; Horita, Satoshi; Murakami, Kazuhiro; Kirita, TadaakiObjectives: The success rate of dental implants depends on the type of bone at the implant site. The purpose of the present study was to investigate the effects of the bone parameters at the implant-placement site on peri-implant bone strain distributions. Study Design: The morphologies and bone densities of seventy-five potential implant sites in the posterior man - dible were measured using computed tomography (CT). Based on the CT data, we defined bone parameters (low and high in terms of cancellous-bone density and crestal-cortical bone density, and thin and thick in terms of crestal-cortical bone thickness), and we constructed finite-element models simulating the various bone types. A buccolingual oblique load of 200 N was applied to the top of the abutment. The von Mises equivalent (EQV) strains in the crestal-cortical bone and in the cancellous bone around the implant were calculated. Results: Cancellous-bone density greatly affected the maximum EQV strain regardless of the density and thick - ness of the crestal cortical-bone. The maximum EQV strains in the crestal cortical-bone and the cancellous bone in the low-density cancellous-bone models (of 150 Hounsfield units (HU) were 1.56 to 2.62-fold and 3.49 to 5.31- fold higher than those in the high-density cancellous-bone models (of 850 HU), respectively. The crestal cortical- bone density affected the maximum EQV strains in the crestal cortical-bone and in the cancellous bone in the low-density cancellous-bone models. The crestal cortical-bone thickness affected the maximum EQV strains in the cancellous bone and in the crestal cortical-bone in the low-density cancellous-bone models. Conclusions: Our results confirm the importance of bone types for the peri-implant bone strain distribution. Cancellous-bone density may be a critical factor for peri-implant bone strain
