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Purpose: To determine the biologic and biomechanical effects of two implant drilling protocols on the cortical bone around implants subjected to immediate loading. Materials and Methods: A total of 48 implants were inserted into the mandibles of six sheep following one of two drilling protocols: undersized preparation (US; n = 24) and nonundersized preparation (NUS; n = 24). Immediately after implant insertion, an abutment was placed on each implant and 36 implants were subjected to 10 sessions of dynamic vertical loads (1,500 cycles, 1 Hz) of 25 N or 50 N. Insertion torque value (ITV) was recorded at implant installation. Resonance frequency analysis (RFA) was measured at implant insertion and at each loading session. Fluorochrome was administered at day 17, and the animals were euthanized after 5 weeks. The removal torque values (RTVs) were measured, and samples underwent histomorphometric, μCT (microcomputed tomography), and fluorescence image acquisition analyses. The bone volume density (BV/TV), bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), and fluorochrome stained bone surface (MS) were calculated. A linear mixed model analysis was performed, and Pearson paired correlation was calculated. Results: Five implants from the NUS group failed, with a mean ITV of 8.8 Ncm and an RFA value of 57. The mean ITVs for US group and NUS group were 80.5 (± 14) Ncm and 45.9 (± 25) Ncm, respectively (P < .001). No differences were noted in the RFA values from the time of implant insertion until the end of the study. No differences in RTV, BV/TV, BAFO, or MS were observed between the groups. Intense new bone formation took place in the NUS group implants that were subjected to load. Conclusions: Undersized preparation of cortical bone ensured a greater BIC compared to a nonundersized preparation. Moreover, this study demonstrated that immediate loading did not interfere with the osseointegration process, but loading induced intense new bone formation in the NUS group. It is not recommended to immediately load the implants when the clinically perceived primary stability is lower than an ITV of 10 Ncm and an RFA value of 60. [ABSTRACT FROM AUTHOR]

Purpose: Patients who have a vertical growth pattern are more prone to complete alveolar bone growth later and run a higher risk for inhibition of growth and infraposition after implants have been placed. Moreover, it has been suggested for the same category of patients that craniofacial height may influence the alveolar bone morphology of the anterior maxilla during growth. Hence, it is important to identify such patients early when considering implant treatment in young patients. The purpose of this study was to investigate the height and width of the alveolar bone in the anterior maxilla in subjects with different craniofacial heights to assess if there is a relation between craniofacial height and the dimensions of the alveolar bone in the anterior part of the maxilla. Materials and Methods: Measurements on cephalograms and cone beam computed tomography (CBCT) images of the maxilla from 180 fully dentate subjects were analyzed and categorized into three angle groups based on the craniofacial height: low-, normal-, and high-angle groups. Measurements of the alveolar bone were taken interradicular, at six reference points distributed between the first premolar regions in the maxilla. The height and width of the alveolar bone were measured with a standardized technique at 3, 6, 9, and 12 mm from the top of the alveolar process. Results: Significant differences were found regarding the height of the alveolar bone in all the subgroups and regarding the width in the 9- and 12-mm subgroups, and between low-/normal- and low-/high-angle groups, where the high-angle group represented the thinnest alveolar bone. A significant difference was found between male and female patients concerning all dimensions of the alveolar bone. Conclusion: There is a relation between craniofacial height and the dimensions of the alveolar bone in the anterior part of the maxilla. Craniofacial height is an important factor to analyze when implant treatment is considered in the maxillary anterior region. This identification can preferably be carried out early in young patients who are still growing when various treatment options can still be considered. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of misfit at implant-level fixed partial dentures (ILFPDs) and marginal bone support on the generation of implant cracks. Materials and Methods: This in vitro study included a mechanical fatigue test and finite element analysis. A mechanical cycling loading test was performed using 16 experimental models, each consisting of two parallel implants subdivided into four groups based on the misfit and the supporting bone condition. The framework, firmly seated at implants, was dynamically loaded vertically with a force of 1,600/160 N and 15 Hz for 1 x 106 cycles. Optical microscope, scanning electron microscope (SEM), and computed tomography three-dimensional (CT-3D) analyses were performed to detect impairments. Finite element models, representing the setups in the mechanical fatigue test, were used to represent the fatigue life. Results: None of the mechanical components presented distortion or fracture at the macroscopic level during the test. In a microscopy evaluation, the fatigue test revealed scratches visible in the inner part of the conical portion of the implants regardless of the groups. SEM and CT-3D analysis revealed one implant from the misfit/no bone loss group with a microfracture in the inner part of the conical interface. The simulated effective stress levels in the coronal body were higher in the misfit groups compared with the no misfit groups. The misfit groups presented effective stress levels, above 375 MPa, that penetrated the entire wall thickness. The no bone loss group presented an effective stress level above 375 MPa along its axial direction. In the no misfit group, the area presenting effective stress levels above 375 MPa in the conical connection was larger for the bone loss group compared with the no bone loss group. Conclusion: This study confirmed that implant fracture is an unlikely adverse event. A clear pattern of effective distribution greater than fatigue limit stresses could be noticed when the misfit was present. The dynamic load simulation demonstrated that the crack is more likely to occur when implants are fully supported by marginal bone compared with a bone loss scenario. Within the limitations of this study, it is speculated that marginal bone loss might follow the appearance of an undetected crack. Further research is needed to develop safe clinical protocols with regard to ILFPD. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the volumetric alterations and osseointegration properties in the augmented area of the ring technique using different types of bone graft material in sheep mandible bone. Materials and Methods: Three different materials (columnar forms, 7-mm diameter, 3-mm height) were stabilized using dental implants with a turned surface in the mandible bone of Finnish Dorset cross-bred sheep: group A, autogenous bone; group B, bovine bone; group C, biphasic bone substitute. Animals were euthanized after 5 weeks (N = 6). Three-dimensional image data by digital oral scanner were taken at the surgery and sacrifice, and the volume alteration of the material was calculated. The bone samples were fixed in formalin and dehydrated in ethanol. Resin-embedded samples were subjected to non-decalcified ground sectioning, and histologic and histomorphometric analysis (bone and material area alteration, bone-to-implant contact [BIC]) were done. Results: In three-dimensional (3D) image analysis, group A showed a statistically higher percentage of remaining materials compared with groups B and C. The histologic observation showed no new bone formations around the implants in all groups, especially at the maxillary site of the implant in the augmented area. In histomorphometric analysis, group A showed a statistically higher percentage of bone area (BA) compared with groups B and C; however, in all groups, bone-to-implant contact (BIC) showed low values, and there were no statistical differences between groups. Conclusion: The results of this study suggested that the autogenous bone maintained bone volume around the dental implant using the ring technique, and the impact of surface properties was of some importance; osseointegration with the turned surface in the augmented area showed low BIC values in all groups. [ABSTRACT FROM AUTHOR]

Purpose: To compile the current evidence on biomechanical, biologic, and clinical outcomes of undersized surgical preparation protocols in dental implant surgery. Materials and Methods: An electronic search using three different databases (PubMed, Web of Science, and Cochrane Library) and a manual hand search were performed including in vitro, animal, and clinical studies published prior to October 2015. Studies in which an undersized drilling protocol was compared with a nonundersized drilling protocol were included. Results: From an initial selection of 1,655 titles, 29 studies met the inclusion criteria, including 14 biomechanical, 7 biologic, 6 biologic and biomechanical, and 2 clinical. Due to methodologic variation, meta-analysis was not performed. Several studies showed that implants inserted with an undersized drilling approach reached a significantly higher insertion torque value than conventional drilling in low-density substrates, while this effect is less evident if a thick cortical layer is present. Similar results in terms of boneto- implant contact (BIC) were achieved in the longer term between implants inserted with undersized and nonundersized protocols. Results in the short term were inconclusive. Clinical studies did not show negative outcomes for undersized drilling, although clinical evidence was sparse. No data are available on marginal bone loss. Conclusion: From the biomechanical standpoint, an undersized drilling protocol is effective in increasing insertion torque in low-density bone. Biologic response in long-term healing after undersized implant placement is comparable to that in the nonundersized surgical drilling protocol. Clinical studies indicate that performing an undersized drilling protocol on low-density bone is a safe procedure; however, more extensive studies are needed to confirm these data. [ABSTRACT FROM AUTHOR]

Objectives: This randomised controlled trial compares the 3‐year outcomes, that is, marginal bone‐level (MBL) changes and clinical parameters, between an abutment‐level (AL) and implant‐level (IL) connection for implants with an internal conical connection (ICC) supporting a screw‐retained fixed partial denture. Material and methods: Fifty patients with 119 implants were randomly allocated to either the AL or IL group. Radiographic and clinical examinations were performed after one, two, and 3 years. A linear mixed model was used to evaluate the differences between groups. Results: The MBL change was not significantly different between the groups at any point. The MBL was 0.12 ± 0.31 mm (AL) and 0.23 ± 0.26 mm (IL) after 1 year; 0.15 ± 0.34 mm (AL) and 0.17 ± 0.22 mm (IL) after 2 years; 0.18 ± 0.39 mm (AL) and 0.15 ± 0.21 mm (IL) after 3 years. The bleeding on probing was 43.44 ± 39.24% (AL) and 58.19 ± 41.20% (IL) after 1 year; 35.78 ± 39.22% (AL) and 50.43 ± 41.49% (IL) after 2 years; 51.27 ± 44.63% (AL) and 49.57 ± 37.31% (IL) after 3 years and was significantly different (p =.025) between 1 and 2 years. The probing depth showed a significant difference at each time point while the plaque was not significant between the groups. The overall technical, biological and prosthetic complication rates were 5.04%, 3.36%, and 16.00%, respectively. Conclusions: The MBL change was similar in the groups. The slight differences in the soft tissue complications between the groups are likely not of clinical relevance. An IL connection is considered to be a valid alternative to an AL set‐up in ICC implants. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of surface hydrophilicity on the biomechanical aspects of osseointegration of dental implants in the tibia and femur of rabbits. Forty-eight mature female New Zealand White rabbits were included, and 96 commercially pure, Grade 4, titanium dental implants (control group), and 96 implants of same macro geometry with the hydrophilic surface (test group) were used in this study. One osteotomy was performed in each tibia and femur on both sides of the rabbit, and four implants were placed in each rabbit. Control and test groups were randomly allocated on the left and right sides. During surgery, insertion torque (ITQ) value of the complete implant placement was recorded. After healing periods of 0, 2, 4, and 8 weeks after surgery, implant stability quotient (ISQ) value, and removal torque (RTQ) values were measured. No statistical difference was observed for ITQ, for ISQ and for RTQ between the control group and test group in tibia/femur for all time periods. The effect of hydrophilic properties on moderately roughened surfaces has no impact in terms of biomechanical outcomes (ISQ values and RTQ values) after a healing period of 2 to 8 weeks in rabbit tibias /femurs. [ABSTRACT FROM AUTHOR]

Objectives: This RCT compares marginal bone level (MBL) change and the clinical parameters after a 3‐year function in maxillary implant‐supported fixed complete dentures (FCDs) treated with four‐implants (4‐I) or six‐implants (6‐I). Material and method: Three centres treated 56 patients with 280 implants allocated to the 4‐I or 6‐I group. Radiographic and clinical examinations were performed. The primary outcome was to investigate MBL change between the groups. Results: Implant survival rates were 100% and 99% in the 4‐I and 6‐I groups, respectively. Considering the clustering effects, the MBL change was not significantly different between the groups over the 3‐year follow‐up. The MBL in the 4‐I group was 0.30 ± 0.50 mm at baseline, 0.24 ± 0.31 mm at 1 year and 0.24 ± 0.38 mm at 3 years. In the 6‐I group, MBL was 0.14 ± 0.32 mm at baseline, 0.16 ± 0.35 mm at 1 year and 0.12 ± 0.26 mm at 3 years. There was a statistically significant difference between the groups at BL and 3Y. No significant differences between the groups were reported for clinical parameters at each time point as well as in between the visits. The technical and biological complications rates were 1.6% and 6.0%, respectively. Prosthetic complications affected 25 FCDs (47.2%). Conclusion: Marginal bone level change revealed a stable condition in the 3‐year period in the two groups. Few technical and biological complications occurred apart from the chipping/fracture of the prosthetic teeth. Four‐implant is a feasible solution if the rehabilitation is oriented towards the most cost‐effective treatment and towards avoiding bone augmentation procedures. Clinicians have to consider the potential required visits for prosthetic maintenance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze the survival rate of endosseous implants placed in the partially dentate maxilla treated with sinus inlay block bone grafts. Materials and Methods: Seventeen patients were subjected to bone augmentation procedures prior to or in conjunction with implant placement. Bone volumes were regarded as insufficient for implant treatment unless a bone grafting procedure was performed. The patients were treated with sinus inlay block bone grafts and endosseous implants in a 1- or 2-stage procedure. A total of 69 implants were placed in the patients who were followed for 29 to 101 months (mean, 53.1 months). The retrospective patient group was also prospectively followed using a standardized clinical and radiographic study design. Results: The implant survival rate was 91.3% (63/69). All implants were lost during the period from abutment connection to connection of the definitive prosthesis. All bone grafts were stable. Bone grafts supported 48 implants, of which 5 failed (10.4%). In the residual bone, 21 implants were placed, of which 1 failed (4.8%). All patients received a fixed partial prosthesis, which was stable during the follow-up period. Conclusion: The results of this investigation revealed a satisfactory clinical outcome of implant placement in grafted partially dentate maxillae after a mean follow-up of 53.1 months. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze and compare the survival rates of endosseous implants placed in the edentulous maxillae of patients in whom bone augmentation was undertaken prior to or in conjunction with implant placement with survival rates in patients who did not undergo bone augmentation. Materials and Methods: This study included 2 retrospective patient groups: the graft group, which included 64 patients with 437 implants, and the nongraft group, which included 118 patients with 683 implants. The patients were treated consecutively between 1990 and 1996. In addition, the retrospective patient groups were also followed prospectively using a standardized clinical and radiographic study design. Results: The implant survival rate was 75.1% for the graft group and 84.0% for the nongraft group after a mean follow-up of 5 to 6 years, a statistically significant difference. However, there was no difference with regard to the prosthesis survival rate, and after reoperation, more grafted patients had a fixed prosthesis at the end of the study (87.5% versus 85.3%). Implant failure appeared to be related to the original jawbone volume in the anterior regions. In the premolar region, where the inlay graft technique was used, the implant survival rate for the graft group was comparable to that of the nongraft group. The graft group had significantly more failures than the nongraft group in the incisor region, but not in the canine, premolar, or molar regions. Discussion: The majority of implant failures occurred before loading. Occlusal overload during the healing period may have been a causative factor. Conclusions: The overall implant survival rate was lower in grafted maxillae than in nongrafted maxillae after a mean of 5 to 6 years of follow-up. Analysis revealed that jawbone volume in the anterior regions at the start of treatment was directly related to implant survival rates in both groups: the greater the volume, the higher the survival rate. Moreover, the implant survival rate was similar in grafted posterior edentulous maxillae of classes V and VI and in nongrafted posterior edentulous maxillae of classes III and IV. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of mandibular dentition on the performance of maxillary implants prior to definitive prosthesis attachment in maxillae that have been reconstructed with autogenous bone grafts. Materials and Methods: A retrospective review of 90 consecutive patients, 31 men and 59 women, with a mean age of 57.4 years, was conducted. All patients underwent treatment planning to receive endosseous implants in the edentulous maxilla in conjunction with autogenous bone grafting. During the time from implant and/or bone graft placement until placement of the definitive restorations in the maxillae, the mandibular dentitions were recorded and categorized into 6 groups based upon the presence and distribution of teeth. Results: Of 643 implants placed, 118 (18.4%) were lost between implant placement and definitive prosthesis placement. The type of mandibular dentition was significantly associated with implant failure during this time interval (P < .001). In particular,the patients with implants opposing unilateral occlusal support showed the highest rate of implant failure (43.8%, or 28 of 64 implants). Implants that opposed a mandibular implant-supported fixed prosthesis demonstrated an implant failure rate of 14.3% (10 of 70), and in patients with a removable mandibular denture, the implant failure rate was 6.2% (4 of 65 implants failed). The overall mean patient follow-up was 64.2 months. At 60 months, the cumulative implant failure rate based on the Kaplan-Meier method was 20.2%. Discussion: Unfavorable concentration of forces on the maxilla may contribute to increased risk of implant failure. Conclusion: Effort should be made to create a favorable occlusion in the mandible, with attention being paid to broad distribution of occlusal contacts. [ABSTRACT FROM AUTHOR]

Congenital absence of multiple teeth and poorly developed alveolar ridges are associated with ectodermal dysplasia. Affected patients often require dental prosthetic treatment during their developmental years. Maxillofacial growth and development in a preadolescent female patient with ectodermal dysplasia following oral rehabilitation with maxillary and mandibular endosseous dental implants is reported. Four maxillary and 4 mandibular implants were successfully integrated and restored at 8 years of age. Growth analysis 12 years later revealed that the implants followed maxillary and mandibular growth displacement. Minor impaction of the maxillary implants was observed, and mandibular implants were affected by the mandibular growth rotation, which led to a change in implant inclination. The treatment outcome is compared to similar previously reported studies and cases. [ABSTRACT FROM AUTHOR]

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Purpose: Paramedial mandibulotomy facilitates access for the resection of tumors in the oral and oropharyngeal space; however, severe complications related to surgical techniques and radiotherapy have been reported for this procedure. This study evaluated whether preservation of the periosteum during a mandibulotomy would decrease postoperative complications owing to the increased healing capacity provided by preserving more tissue.Materials and Methods: Patients who underwent mandibulotomy for surgical tumor ablation from 2007 through 2012 were included in a retrospective controlled cohort study. The trial was comprised of 2 groups: 1 group underwent subperiosteal and 1 group underwent supraperiosteal surgical dissection in the area of the mandibulotomy. The primary predictor variable was surgical technique and the primary outcome variable was surgical complications. The groups were matched according to tumor type, age, and gender. Clinical and radiographic follow-up was performed 12 months after surgery. Complications regarding bone exposure, plate exposure, osteoradionecrosis, nonunion, infection of the soft tissue flap, abscesses, fistulas, and gingival necrosis were recorded. Recordings of other factors, such as age, smoking habits, and timing of radiotherapy and chemotherapy, were performed and the 2 groups were compared for postoperative complications. Data analysis used the χ(2) test (Fisher exact test) to compare the sub- and supraperiosteal groups for postoperative complications.Results: Thirty-two patients were included (16 per group; 14 women and 18 men; mean age, 56 yr). Thirteen patients in the subperiosteal group and 7 in the supraperiosteal group showed complications during the first 12 months. Seven patients had complications that persisted to the 12-month follow-up (6 in the subperiosteal group and 1 in the supraperiosteal group); however, the difference was not statistically relevant.Conclusion: This study found more persistent complications in the subperiosteal group compared with the supraperiosteal group at 12-month follow-up, which could imply that a more tissue-preserving surgical technique promotes mandibular healing in patients undergoing mandibular access osteotomy in combination with radiotherapy. [ABSTRACT FROM AUTHOR]

In order to determine a suitable thickness of polyetheretherketone (PEEK) for manufacturing of surgical membranes, the purpose was to evaluate how different thicknesses of PEEK influence the mechanical properties under flexure and tension. In total 20 specimens in PEEK with two different thicknesses, 0.5 mm and 1.0 mm were fabricated and tested in a three-point flexural strength test and tensile strength test (n = 5 specimens). Statistical analysis was done with non-parametric Mann-Whitney test with level of significance α = 0.05, for both material tests, respectively. The 1.0 mm-thick samples resulted in higher values in elastic limit and conventional deflection (S c -value) in the flexural strength test compared to 0.5 mm-thick samples. In the tensile strength test, the results did not show any significant difference in elastic limit depending on the thickness evaluated. However, PEEK with thickness of 1.0 mm received significantly higher maximum value at fracture. Within the limitations of this study, PEEK with a thickness of 0.5 mm–1.0 mm shows mechanical properties that are appropriate thickness and can meet the complex demands for dimensioning of surgical membranes. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the volumetric alterations and osseointegration properties in the augmented area of the ring technique using different types of bone graft material in sheep mandible bone., Materials and Methods: Three different materials (columnar forms, 7-mm diameter, 3-mm height) were stabilized using dental implants with a turned surface in the mandible bone of Finnish Dorset cross-bred sheep: group A, autogenous bone; group B, bovine bone; group C, biphasic bone substitute. Animals were euthanized after 5 weeks (N = 6). Three-dimensional image data by digital oral scanner were taken at the surgery and sacrifice, and the volume alteration of the material was calculated. The bone samples were fixed in formalin and dehydrated in ethanol. Resin-embedded samples were subjected to non-decalcified ground sectioning, and histologic and histomorphometric analysis (bone and material area alteration, bone-to-implant contact [BIC]) were done., Results: In three-dimensional (3D) image analysis, group A showed a statistically higher percentage of remaining materials compared with groups B and C. The histologic observation showed no new bone formations around the implants in all groups, especially at the maxillary site of the implant in the augmented area. In histomorphometric analysis, group A showed a statistically higher percentage of bone area (BA) compared with groups B and C; however, in all groups, bone-to-implant contact (BIC) showed low values, and there were no statistical differences between groups., Conclusion: The results of this study suggested that the autogenous bone maintained bone volume around the dental implant using the ring technique, and the impact of surface properties was of some importance; osseointegration with the turned surface in the augmented area showed low BIC values in all groups.

Unlabelled: The aim of this retrospective study was to assess the frequency of postoperative bleeding in patients on warfarin after tooth removal followed by a complete soft tissue closure of the surgical site. A total of 124 consecutive patients, 69 males and 55 females with a mean age of 71 years (range 28-95 years) were included in this study. Inclusion criteria were patients on warfarin with an INR