جستجوی مقالات مرتبط با کلیدواژه « Dental implants » در نشریات گروه « پزشکی »

This study useda newly designed mesiodistal guide set to assess and compare the precision of the mesiodistal positioning of dental implants relative to adjacent teeth. The cost-effective and convenient guide set wascompared to the conventional freehand surgery technique in partially edentulous patients.

The study enrolled 38 patients requiring at least one implant. Participants were divided into case and control groups, receiving 30 implantsin each group:10 in free-end areas, and 20 in single-tooth edentulous spaces. In the case group, implants were placed using the mesiodistal guide set, while the control group underwent the freehand procedure. The postoperative evaluation involved taking parallel periapical radiographs to measure distances and angles between the implants and adjacent teeth using Photoshop CS4. The data was rigorously analyzed using the Generalized Estimating Equations (GEE) method, a statistical technique for modeling clustered data, with statistical significance set at p<0.05.

Measurements of the mesiodistal distances between implants and adjacent teeth showed reduced deviations in the case group, with statistically significant differences in mesial (P=0.001) and distal (P=0.036) distances. The tooth-supported area exhibited better outcomes compared to the free-end area. However, there were no significant differences in implant-tooth angulation, whether mesial (P=0.503) or distal (P=0.188).

The study indicated that the mesiodistal guide set offers practical guidance for positioning implants next to teeth in partially edentulous patients. This finding has significant practical implications, providing tangible evidence for the clinical application of the guide set. Despite some limitations, the findings fall within clinically acceptable parameters, and the guide set proved to enhance accuracy over the freehand method

Statement of the Problem:

 The satisfaction of patients with dentures on implants has different points of view that become fundamental aspects for the development of research on the quality of life of these patients, the eventual biomechanical complications to which these prostheses and implants can be subjected, and design considerations for cantilever extensions.

The objective of research was to assess the implants and prosthesis survival rates, biomechanical complications relative to the length of the distal extensions (cantilevers), and the satisfaction of the patients with a fixed implant-supported full-arch fiber-reinforced composites prosthesis.

A retrospective clinical and radiographic cohort study was developed. Clinical records of a selected cohort were analyzed according to inclusion and exclusion criteria. Data on a patient who underwent to fixed implant-supported full-arch fiber-reinforced composites prosthesis at least of five years of function were collected. Data analysis was performed using Kaplan-Meier curves and Fisher's Exact Test. P values less than 0.05 were considered statistically significant.

After insertion, 1 of 29 prostheses failed, the overall prosthetic survival rate observed at 5 years was 96.5%. Of the 120 implants placed in 28 patients, only 4 patients experienced loss of an implant during the 5 years of observation; the implant survival rate throughout the observation period was 86.2%. Distal extension seems to negatively affect the prognosis of implant-supported rehabilitation. Regarding the level of satisfaction of the patient with the prosthesis, none reported being uncomfortable or dissatisfied neither with their appearance nor with the taste of food throughout the studied period.

No relevant associations were found between the variables involved. The study found the improvement in quality of life following the installation of fixed rehabilitation on the patients. Once the potential benefits of patients are obtained, controlled clinical trials are encouraged.

The focus of this review study was to examine and analyze the impact of vitamins and minerals on dental implants.

In order to obtain information on the effects of vitamins and minerals on dental implants, a group of existing articles was thoroughly examined for their findings. This examination process involved the selection of specific articles that met the necessary criteria to be included in the analysis, which were then subjected to an extensive review process. The duration of this review process was over a time span of 11 years, starting from the year 2011 and concluding in the year 2022.

A total of 23 articles were included in the study, consisting of 9 clinical studies, 6 animal studies, 1 laboratory study, and 7 reviews. Clinical studies were limited due to uncertain results regarding the impact of vitamins and minerals on DIT, with most focusing on vitamin D levels rather than other nutrients.

It has been concluded that vitamins and minerals play an important role in forming bone tissue. The lack of these essential elements may result in several diseases, such as diabetes mellitus and osteoporosis. It is therefore recommended to increase the levels of vitamins and minerals in patients before undergoing dental implant treatment (DIT), even though the quality of the patient’s bone can also impact the success of the implant. Consequently, the patient’s diet should be modified, and essential supplements and vitamins should be administered to ensure optimal implant success.

 Non-ionizing electromagnetic field (EMF) exposure therapies are non-invasive and safe treatment options that can potentially change available treatments. In this review, we examined the applications of such therapies in dental implant surgery by conducting a systematic review.

A comprehensive search of several international electronic databases was conducted from inception to December 14, 2022. This review included interventional studies that evaluated the advantages of adjunctive magnetic or combined EMFs on dental implants compared to conventional treatments.

 From a total of 1695 studies, 12 preclinical and clinical studies were selected, discussing EMF-based treatments for enhancing implant stability, osteogenesis, and osseointegration, as well as alleviating post-implant surgery manifestations. Almost all studies on maxillary and mandibular implant stability showed beneficial effects of non-ionizing EMF in humans. Most studies evaluating osteogenesis and osseointegration indicated that EMF exposure could accelerate bone repair and peri-implant bone formation and increase bone contact ratios, bone volume fraction (bone volume/total volume), trabecular number, and trabecular thickness. Only two clinical studies examined the effect of EMF on pain and swelling after dental implant surgery, with one finding that subjects exposed to EMF used analgesics fewer times and in far lower doses than the control group and the other finding no significant difference in reducing these outcomes between the groups.

 Overall, devices that deliver non-ionizing low-level EMF can be a viable and widely recognized non-invasive adjuvant therapy for attaining success and better outcomes after dental implant surgery due to their efficacy, safety, and short exposure time.

Keratinized mucosa width (KMW) has an essential role in peri-implant health. This study aimed to evaluate the impact of KMW on marginal bone loss (MBL) around overdenture-supported dental implants.

In this cohort study, completely edentulous patients received an overdenture with implants in the maxilla and mandible. Two implants were placed in the maxilla and mandible. Ball attachments were used. KMW was measured, and gingival biotype was determined. MBL was evaluated on digital parallel radiographs taken at 12 and 24 months after loading. KMW was the predictive factor, and MBL was the outcome of the study. Data were analyzed using SPSS 21 via Pearson’s correlation test, independent t-test, and Chi-square test (alpha=0.05). 

Eighty implants in 20 patients were studied. The mean KMW was 2.05±0.88 mm. The mean MBL was 1.32±0.46 mm at 12 months after loading, and 1.71±0.49 mm at 24 months after loading. Analysis of the data demonstrated a correlation between MBL at 12 and 24 months after loading with KMW and dental implant diameter (P<0.001).

It appears that narrow KMW may be associated with an increase in MBL in two-implant-supported overdentures. Gingival biotype may play a role in the detrimental effect of narrow keratinized mucosa on MBL.

This study aimed to assess the influential factors on selection of implant treatment by patients and their correlation with outcome satisfaction.

This cross-sectional study was conducted on 135 patients requiring dental implant treatment. Information regarding the influential factors on selection of implant treatment by patients was collected using a valid and reliable questionnaire, and the correlation of influential factors with outcome satisfaction was analyzed by the Pearson and Spearman correlation tests. Data were analyzed by independent t-test, Kruskal-Wallis test, Mann-Whitney test, Chi-square test, and one-way ANOVA (alpha=0.05). 

Advice from dentists was the most common reason (50.4%) for selection of implant treatment. Knowledge of patients about implant treatment had a significant correlation with their outcome satisfaction (P=0.003) but had no correlation with dental clinician’s satisfaction with the treatment outcome (P=0.054). Knowledge of patients about implant treatment had a significant correlation with the time interval between the date of advice from their dentist and time of seeking dental implant treatment (P=0.024), and their level of education (P<0.001).

Patients had optimal knowledge level about implant treatment, and dentists had the most important role in knowledge enhancement of patients and convincing them to seek dental implant treatment. Knowledge level of patients had a significant correlation with their satisfaction with the outcome.

The aim of this study was to investigate the influence of abutment material, alveolar bone density, and occlusal forces on stress distribution around maxillary anterior implants.

An in‑vitro study was conducted. The maxillary anterior implant was modeled using a three‑dimensional finite element model in D2 and D3 bones with three different abutment materials: titanium, zirconia, and poly‑ether‑ether ketone (PEEK). Von Mises stress was evaluated after the application of vertical and oblique loads of 100 N, 175 N, and 250 N. Statistical analysis was done by Friedman–Wilcoxon signed‑rank test, Mann–Whitney U test, and Kruskal– Wallis test. The probability value <0.05 is considered a significant level.

Stress distribution around D3 bone was higher than D2 bone in all the abutment materials with greater values seen in oblique load than vertical load with insignificant difference (P > 0.05). Statistically insignificant stress values were seen greater in PEEK than titanium or zirconia abutment (P > 0.05). A statistically significant difference was observed between 100 N and 175 N of load (P < 0.05).

PEEK, zirconia, and titanium as abutment material in the anterior region showed similar properties. The stress on the bone was proportionately increased during the vertical and oblique loads suggesting the influence of mechanical load in crestal bone loss rather than the type of abutment material.

 The objective of the current research was to evaluate how stress is distributed in the peri-implant bone of a mandibular overdenture with implants placed asymmetrically to the midline.

 A 26-year-old male’s mandible, with missing teeth, was examined using computed tomography (CT) scanning. Two implants were inserted at right angles to the occlusal plane, in the positions of the right canine and left lateral incisor of the mandible, with an internal connection. Two types of attachments (bar and ball) were designed. To simulate the clinical condition, anterior (on central incisors) and bilateral posterior (on premolars and molars) loadings were applied. The stress distribution was assessed using finite element analysis (FEA).

 The lateral incisor level implant was found to have the highest maximum principal stress (about 33 MPa) in both models in the anterior loading condition. However, in both models, the canine-level implant revealed more stress values (about 22 MPa) in the posterior loading condition.

 In mandibular implant-supported overdentures, when implants were placed asymmetrically to the midline, one acted as a fulcrum and sustained more occlusal load. The bar attachment system did not reveal superior results in terms of stress distribution compared to the ball attachment.

 A key factor for the success or failure of an implant is how the stresses are transferred to the surrounding bone. The implant‒abutment connection (IAC) is paramount for implant success. The purpose of this finite element analysis (FEA) study was to evaluate the stress distribution in and around three different implant‒abutment interfaces with platform-switched and platform-matched abutments using the finite element method (FEM).

 Three distinct types of IAC were selected: tri-channel internal connection, conical connection, and internal hex connection. Six models were generated, three in platform-switched and three in non-platform-switched configuration. Computer-Aided Three-Dimensional Interactive Application (CATIA) V5 R20 software was used to generate virtual models of the implants and the mandible. The models were transferred to Analysis of Systems (ANSYS) 15.0 software, in which the models were meshed and underwent FEA.

 On the crestal bone, the highest von Mises stresses in platform-switched abutments were noticed in the internal hex implant‒abutment system (370 MPa), followed by the tri-channel implant‒abutment system (190 MPa) and conical implant‒abutment system (110 MPa). On the implant and the abutment screw, the highest von Mises stresses were observed in the internal hex implant‒abutment system, followed by the conical implant abutment system and tri-channel implant‒abutment system. Platform-switched implants had a more favorable stress distribution on crestal bone.

 Within the constraints of the current study, the internal hex connection exhibited the highest stress. In contrast, the conical abutment connection with platform switching configuration had more favorable stress distribution in crestal bone than other implant abutment systems.

Osteogenic, antioxidant and anti-inflammatory effects of Whey protein and M. oleifera gel prompted us to evaluate their role alone or in combination on osseointegration in rabbits.

In this study, 24 titanium implants were inserted in the femurs of six rabbits. One implant was placed without treatment, and another one was coated with a mixture of whey protein and M. oleifera gel for each side.  The animals were divided into two groups of 2- and 6-week intervals and evaluated using histopathological and immunohistochemical techniques.

Histological evaluation revealed a significant difference between the experimental and the control groups after two weeks in osteoblast and osteocyte counts. The experimental group had mature bone development after six weeks of implantation, while the control group had a woven bone. Immunohistochemical results showed that the experimental group, compared to the control group, exhibited early positive expression of osteoblast cells at two weeks after the experiment. Based on histopathological observations, the experimental group showed a tiny area of collagenous fiber in 6th week after the implantation.

A mixture of whey protein and M. oleifera could accelerate osseointegration and healing processes.

The use of dental implants to restore edentulous jaws has become commonplace. Usually, in the maxilla, following a tooth extraction, the height of alveolar bone decreases. This alteration in bone increases the risk of implants migrating into the sinus. In general, Caldwell-Luc and endoscopic surgery are performed to retrieve dental implants. In this case series, we collected data from 39 patients who had the complication of implant displacement within the maxillary sinus for 25 years. All the implants were removed using the Caldwell-Luc technique. Implant migration happened following functional loading, during the prosthetic procedure, due to lack of osseointegration in 3 patients, and during implant placement into the fresh socket in 3 patients. In the remaining cases, migration occurred preoperatively or postoperatively and prior to implant loading. Insufficient bone quantity is sometimes causing the implant to migrate to the maxillary sinus. In case of minimal bone height, a sinus lift before implant placement should be conducted. Retrieval of an implant pushed inside the maxillary antrum using the Caldwell Luc approach proved to be a reliable technique.

Conventional obturator prostheses might cause dissatisfaction in patients with hard or soft palate defects due to inadequate retention and function during speech, mastication, and swallowing. Thus, surgical reconstruction and implant-supported obturators are considered as alternative treatments for these patients. This case-report study describes the prosthetic reconstruction of an 88-year-old patient suffering from a hard palate defect after surgical resection of verrucous carcinoma in the left side of the hard palate. Fifteen months after radiotherapy, two implants were placed in the right side of the remaining ridge, in the second and third molar region. After the implant healing period, the implant-supported obturator prosthesis was fabricated. The patient was satisfied with the esthetics and function of the obturator at the 12-month recall visit and radiographs showed normal healing and no bone loss around the implants.

The aim of this retrospective study was to assess the dimensions of the mandibular molar socket for immediate implant placement, using cone-beam computed tomography (CBCT) imaging.

The CBCT images of 81 patients were selected based on the inclusion and exclusion criteria. In the OnDemand software, measurements were assessed by virtually positioning a regular Straumann implant (4.8 mm) in the regions of the first and second mandibular molars. The socket morphology, the buccolingual width of cancellous bone, the gap between the implant and the socket wall, the length of the root, the cross-sectional morphology of the mandible, and the height and thickness of the inter-radicular septum were all determined. The variables were compared using either the Student’s t-test or the Mann-Whitney U test.

Among the cross-sectional morphologies of the mandible, the undercut type (U) was found to be the most prevalent. The mean distance of the implant from the inferior alveolar nerve (IAN) was found to be 6.22 mm for the first molars and 5.17 mm for the second molars. Moreover, the mean horizontal distances from the implant to the mesial and distal socket walls were 2.01 and 2.30 mm for the first molars and 2.14 and 2.59 mm for the second molars, respectively. The width of the interradicular septum across various sections was found to have a significant correlation with the position of the tooth (P<0.05).

The majority of the samples exhibited the undercut (U type) morphology of the mandible. The interradicular septum in the second molar tooth was found to be insufficient. Overall, the assessment of pre-extraction CBCT scans and the virtual positioning of implants can be beneficial for surgical treatment planning. This approach can also aid in minimizing potential complications.

This study aimed to evaluate radiofrequency-induced heating of different amalgam restorations and dental implants during 1.5T magnetic resonance imaging (MRI).

Standardized class I cavities (5 mm long, 3 mm wide, and 3 mm deep) were prepared on the occlusal surface of 45 extracted human third molars. The samples were restored by three different types of amalgam including Cinalux amalgam (non-gamma-2, spherical), GS-80 (non-gamma-2, admix), and GK-110 amalgam (non-gamma-2, admix in silver). As a separate intervention group (G4), five titanium mini drive-lock implants with 2mm diameter and 10mm length were also selected and mounted to the base of the Eppendorf tube with 3mm of the implants extending above the mounting putty. The box containing the specimens was placed parallel to the long axis of the standard head and neck coil of the MRI device (64MHz radio-frequency energy with 25kW amplifier, 1.5T). Temperature fluctuations of the metallic materials in each group were monitored during MRI scans using a calibrated thermometer. One-way ANOVA was used to compare temperature changes among the amalgam groups (P<0.05).

Temperature elevations ranged from 0.21°C to 0.70°C in amalgam restorations and from 0.35 to 0.47°C in dental implants. The temperature changes among the three amalgam agents were not statistically significant.

According to our findings, the radiofrequency-induced heating of amalgam restorations and dental implants during MRI examination can be considered within acceptable ranges. Therefore, amalgam restorations and dental implants can be categorized as "MR safe" in terms of radiofrequency-induced heating during 1.5 T MRI.

The success rate of dental implants diminishes over time; the lack of osseointegration and infection are the major causes of most implant failures. One of the effective methods to improve the surface properties is to irradiate ultraviolet (UV) light. This study investigated the effect of UV photofunctionalization on the ultrasuperficial properties of sandblasted, large-grit, acid-etched (SLA) titanium discs.

In this in vitro study, 24 sandblasted and acid-etched titanium discs, with a lifespan of more than four weeks, were categorized into three groups (n=8): control, ultraviolet C (UVC), and ultraviolet B (UVB). Then, they were exposed to a UV light source for 48 hours at a 1-cm distance. In addition to measuring the contact angle between the liquid and the disc surface in each of the three groups, the atomic concentrations of carbon, oxygen, and nitrogen atoms were measured at three different sites on each disc. One-way ANOVA and post hoc Tukey tests were used to analyze data.

The mean concentration of carbon atoms significantly differed in the control, UVC, and UVB groups (P<0.001). The mean concentrations of nitrogen atoms differed significantly between the three groups (P<0.001). However, the mean concentrations of oxygen atoms were not significantly different between the three groups. In examining the contact angle, wettability was higher in the UVC group than in the UVB group and higher in the UBV group than in the control group.

Photofunctionalization with UV light significantly decreased carbon and nitrogen concentrations on the surface of titanium implants, indicating that the implant’s superficial hydrocarbons were eliminated. It was observed that UVC photofunctionalization was more effective than UVB photofunctionalization in reducing superficial contamination and improving wettability.

Alveolar bone resorption may complicate dental implantation of the edentulous area. The quantity of residual bone depends on the region, and it is uncertain which region may present more difficulties before implantation. In this study, the alveolar bones of patients who had cone beam computed tomography (CBCT) before dental implantation were examined, and residual bone was evaluated based on age, gender, and the location of the missing tooth.  

In this observational study, the patients with CBCT were divided into two age groups: 18 to 35 and 36 and older. Also,  the edentulous regions were divided into incisor, premolar, and molar regions. Radiographic measurements were performed with a cross-sectional aspect in the single-tooth deficiency regions of the patients; bone height and width measurements were made.  

This study included 164 CBCT scans from individuals (99 females and 65 males). There was no statistically significant difference between the bone heights and between bone widths at the 1st, 3rd, 5th, and 7th mm according to age or gender  (P>0.05). Bone height in the incisor tooth region (ITR) and bone width at the 1st, 3rd, 5th, and 7th mm in the molar tooth region  (MTR) were significantly larger (P<0.01).  

This study revealed that the bone width at the 1st mm of the ITR was insufficient for dental implant placement and that horizontal bone augmentation was needed.

The purpose of this study was to conduct a randomized controlled clinical trial to compare and evaluate the effect of provisional restorations fabricated by two techniques, namely, conventional and three‑dimensional (3D) printing processes on the peri‑implant hard and soft tissues over early nonfunctional loaded implants in the mandibular posterior region.

A randomized controlled clinical trial was conducted across 24 subjects broadly divided into two groups with 12 dental implants each, i.e., GpIC with conventionally fabricated provisional restoration and GpIID with 3D printed fabricated provisional restoration. The prosthetic phase was carried out at 2 weeks, and subjects were evaluated at baseline (at the time of prosthesis placement), 2 months, and 4 months for peri‑implant marginal bone level, mucosal suppuration, sulcular probing depth, and modified sulcular bleeding index. Patient satisfaction was assessed using 5‑item questionnaires at 4 months. The intragroup comparison for all the data was done using Wilcoxon signed‑rank test. The intergroup comparison for all the data was done using Mann–Whitney U‑test. The comparison of frequency of responses between GpIC and GpIID was done using Chi‑square test. P < 0.05 was considered to be statistically significant.

Nonsignificant difference was observed in all the hard and soft tissue parameters between the groups at baseline, 2 months, and 4 months (P ˃ 0.05). Improvement in bleeding on probing was found to be greater around dental implants restored with 3D printed provisional restoration than dental implants restored with conventionally fabricated provisional restoration from baseline to 4 months of follow‑up, and the difference in finding was statistically significant (P < 0.05). There was a statistically nonsignificant difference seen for the frequencies between the groups (P > 0.05) for all questions related to patient satisfaction.

The effect of conventionally fabricated and 3D printed provisional restorations on peri‑implant hard and soft tissues was comparable to each other on an early nonfunctionally loaded implant in the mandibular posterior region.

This study aimed to assess the shape and size of the nasopalatine canal (NPC) using cone beam computed tomography (CBCT) in Iranian patients. This cross-sectional descriptive study investigated 285 CBCT scans of the anterior maxilla, obtained from patients in Rafsanjan, Iran. The shape of the nasopalatine canal was categorized as banana (twisted), funnel (diverging towards the oral or nasal cavity), cylindrical, and hourglass. The length and diameter of the canal were measured using multiplanar images. Labial bone thickness was recorded at two points: A at the incisive foramen and B at the foramen of Stenson. Kruskal-Wallis and chi-square tests were used for analysis at P<0.05. The hourglass shape was the dominant canal model in the sample. The mean canal length and the mesiodistal and labiopalatal diameter (at incisive foramen) were 11.17 ± 2.5 mm, 3.6 ± 1.2 mm, and 3.4 ± 1.2 mm, respectively. Moreover, the mean bone thickness at points A and B were 6 ± 1.4 and 8 ± 4.4 mm. A significant difference was found among different canal shapes concerning bone thickness at point B (P=0.01) and labiopalatal width of the canal (P<0.001). There was a direct and significant relationship between the patient’s age and the mesiodistal and labiopalatal widths of the NPC (P=0.001 and P=0.015, respectively). Concerning the age-related and race-related variations in nasopalatine canal morphology, CBCT scans are recommended for accurate evaluation before implant placement or orthodontic retraction in the anterior maxilla.