Prosthetic and Mechanical Parameters of the Facial Bone under the Load of Different Dental Implant Shapes: A Parametric Study

Biomechanical Evaluation of the Osseointegration Levels of Implants Placed Simultaneously With Tibia, Femur, and Jaw Allogeneic Bone Grafts

In implant-supported prosthetic treatments, the jaw bones may not always have enough bone to accommodate implants. Allogeneic grafts can also be preferred as an alternative to autogenous grafts in cases of vertical and horizontal bone deficiencies. The aim of this study is to evaluate the osseointegration levels of lathe-faced titanium implants placed together with allogeneic bone tissue transplants obtained from tibia, femur, and mandible bones using a biomechanical method. Twenty-eight female Sprague Dawley rats were included in the study. The subjects were divided into groups where bone transplantations were performed together with implant placement from the tibia (n=7), femur (n=7), and lower jaw (n=7) regions. Four rats (left and right) were used as donors. Grafts, along with implants, were surgically placed in the corticocancellous part of the metaphyseal parts of the tibia bones of rats. At the end of the 2-week experimental setup, all rats were killed, and the implants and surrounding bone tissues were subjected to biomechanical reverse torque analysis (N/cm), no statistical difference was detected in terms of bone-implant fusion between the groups in which the femur and tibia bones were transplanted (P>0.05), while the bone-implant fusion value in the group in which the lower jaw bone was transplanted was found to be statistically higher than the femur and tibia bones (P<0.05). Based on the limited results of this study, it can be thought that the lower jaw allogeneic jawbone has a higher osseointegration potential than allogeneic grafts obtained from the femur and tibia.

Digital Protocol to Record Occlusal Analysis in Prosthodontics: A Pilot Study

Background: Digital technologies enable the accurate replication of occlusion, which is pivotal for stability in maximum intercuspation and dynamic occlusion. CAD softwares generates standardized occlusal morphologies requiring significant adjustments. The consideration of individual mandibular movements during restoration leads to better functional integration. This pilot study evaluates the efficacy of a novel, fully digital protocol for occlusal analysis recording in prosthodontics. Methods: Patients needing single or multiple metal-free restorations were included. Teeth underwent horizontal finish line preparation, while restorations on implants were either directly screwed or used multi-unit abutments. A digital impression (Trios 3 Intraoral Scanner) captured the mouth's elements. Dynamic occlusion was recorded via Patient Specific Motion (PSM). After the placement and functionalization of temporary restorations, subsequent scans included various elements, and CAD software (Dental system) was used for the restoration design. Restorations were milled in monolithic zirconia, pressed from CAD/CAM-milled wax, and sintered. Results: An evaluation of 52 restorations in 37 patients indicated high accuracy in restorations manufactured via the fully digital workflow. Monolithic zirconia was predominantly used. Subtractive (17.3%) and additive (7.7%) occlusal adjustments were mainly chairside. Conclusion: This study underscores the efficacy of meticulous verification measures and a centric contact system in reducing the need for clinical occlusal refinements in prosthetic restorations.

Silver coating on dental implant-abutment connection screws as potential strategy to prevent loosening and minimizing bacteria adhesion

Introduction: One of the main problems for the long-term behavior of dental implants are loosening of the implant-abutment connection screws and bacterial infiltration. The aim of this work is to increase the screw fixation by silver coating, providing superior mechanical retaining and antibacterial effect. Methods: Eighty dental implants with their abutments and screws have been studied. Twenty screws were not coated and were used as a control while the rest of screws were silver coated by sputtering, with three different thickness: 10, 20 and 40 μm and 20 screws per each thickness. Coating morphology and thickness were determined by scanning electron microscopy using image analysis systems. The screws were tightened for each of the thicknesses and the control with two torques 15 Ncm and 20 Ncm and tested under mechanical fatigue simulating oral stresses up to a maximum of 500,000 cycles. The remaining torques at different cycles were determined with a high-sensitivity torquemeter. Cell viability assays were performed with SaOs-2 osteoblasts and microbiological studies were performed against Streptococcus gordonii and Enterococcus faecalis bacteria strains, determining their metabolic activity and viability using live/dead staining. Results: It was observed a decrease in torque as cycles increase. For a preload of 15 Ncm at 100,000 cycles, the loosening was complete and, for 20 Ncm at 500,000 cycles, 85% of torque was lost. The silver coatings retained the torque, especially the one with a thickness of 40 μm, retaining 90% of the initial torque at 500,000 cycles. It was observed that osteoblastic viability values did not reach 70%, which could indicate a slight cytotoxic effect in contact with cells or tissues; however, the screw should not be in direct contact with tissue or living cells. Silver coating induced a significant reduction of the bacteria metabolic activity for Streptococcus gordonii and Enterococcus faecalis, around 90% and 85% respectively. Discussion: Therefore, this coating may be of interest to prevent loosening of implant systems with a worthy antibacterial response.

Impact of locally delivered diphosphonates on dental implants: A systematic review and meta-analysis

INTRODUCTION

Dental implants are a common solution for edentulous patients. This systematic review and meta-analysis aimed to determine whether locally delivered diphosphonates influence the osseointegration of dental implants in humans.

MATERIAL & METHODS

In March 2023, we conducted an electronic systematic literature search using three databases (MEDLINE/PubMed, Embase, Web of Science). We included randomized trials documenting locally delivered diphosphonates in partly edentulous patients. Two independent reviewers evaluated study eligibility, extracted data, and assessed study quality.

RESULTS

We have identified 752 studies, out of which 7 studies involving 154 patients met the inclusion criteria. The overall meta-analysis indicates that diphosphonates are associated with marginal bone loss during the pre-loading period (mean difference (MD) of -0.18 mm, 95% CI -0.24 to -0.12, p<0.00001; I²=83%), marginal bone loss after one year (MD -0.35 mm, 95% CI -0.56 to -0.14, p = 0.0009; I²=14%), and five years loading (MD -0.34 mm, 95% CI -0.56 to -0.13, p = 0.002; I²=0%). However, the drug did not seem to affect the implant survival rate (risk ratios (RR) of 1.02, 95% CI 0.98 to 1.08, P = 0.33; I²=9%).

DISCUSSION

This study suggests that local use of diphosphonates does not affect implant survival, but it does reduce marginal bone loss and improve the osseointegration of dental implants in humans. However, future research must be more standardized and address methodological biases to draw more conclusive findings.

Biomechanical Analysis of Titanium Dental Implants in the All-on-4 Treatment with Different Implant-Abutment Connections: A Three-Dimensional Finite Element Study

The type of implant-abutment connection is one of the factors influencing the distribution of occlusal forces. This study aims to investigate the biomechanical performance of the mandibular all-on-4 treatment with different implant-abutment connections. Two connection types with 30° abutments and 18-mm implant fixtures were chosen for the posterior implants of the all-on-4 assembly. For the external hexagon connection (EHC) group, the implants with 4 mm in diameter were used. For the internal hexagon connection (IHC) group, we selected implants with 4.3 mm in diameter. A vertical force of 190 N was applied to the cantilever region. The FEA results indicated that the most stressed region in the two groups was prosthetic screws, followed by multi-unit abutments (MUAs). The lowest values of von Mises stress were both observed on the bone. The peak stress value of the implant screw and implant fixture in the EHC group were 37.75% and 33.03% lower than the IHC group, respectively. For stress distribution patterns, the load force tended to be concentrated at locations where components were interconnected. The EHC and IHC are clinically durable under the tested loading conditions, but the prosthetic screws and MUAs can be the weak point on the posterior implant within the mandibular all-on-four assembly. The peak stress values of implant screw and implant fixture in the EHC groups were lower than the IHC group.

Biomechanical behavior of carbon fiber-reinforced polyetheretherketone as a dental implant material in implant-supported overdenture under mandibular trauma: A finite element analysis study

Context

Implant-supported overdentures are well-known and widely accepted treatment modality to increase retention which is a crucial factor for determining patient satisfaction. The placement of two implants in the anterior region can be selected as a first-line treatment in patients with the atrophic mandibular ridge.

Aims

The purpose of this research was to assess the biomechanical effects of carbon fiber-reinforced polyetheretherketone (CFR-PEEK) implant-supported overdenture in the event of 2,000 N forefront trauma to an atrophic edentulous mandible by using the finite element analysis method.

Materials and Methods

Three types of mandible models were simulated; the first one was an edentulous atrophic mandible model; in the second model, 3.5 × 11.5 mm CFR-PEEK implants; and in the third model, 4.3 × 11.5 mm CFR-PEEK implants were positioned in the region of the lateral incisor of the identical edentulous atrophic mandible.

Results

Maximum Von Misses stresses 979.261 MPa, 1,454.69 MPa, and 1,940.71 MPa and maximum principal stresses 1,112.74 MPa, 1,249.88 MPa, and 1,251.33 MPa have been detected at the condylar neck area and minimum principal stresses - 1,203.38 MPa, -1,503.21 MPa, and - 1,990.34 MPa have been recorded at the symphysis and corpus regions from M1 to M3, respectively. In addition, the M2 and M3 models showed low-stress distributions around the implant-bone interface, particularly where the implants were in contact with cancellous bone.

Conclusions

The results showed that the insertion of different diameters of CFR-PEEK implants led to low and homogenous stress distribution all around the implant-bone interface and stresses transferred directly to the condylar neck areas. Therefore, it was observed that CRF-PEEK implants did not change the basic behavior of the mandibula in response to frontal stresses.

Effect of short implant crown-to-implant ratio on stress distribution in anisotropic bone with different osseointegration rates

OBJECTIVE

This study aimed to provide evidence for the clinical application of single short implants by establishing an anisotropic, three-dimensional (3D) finite element mandible model and simulating the effect of crown-to-implant ratio (CIR) on biomechanics around short implants with different osseointegration rates.

METHODS

Assuming that the bone is transversely isotropic by finite element method, we created four distinct models of implants for the mandibular first molar. Subsequently, axial and oblique forces were applied to the occlusal surface of these models. Ultimately, the Abaqus 2020 software was employed to compute various mechanical parameters, including the maximum von Mises stress, tensile stress, compressive stress, shear stress, displacement, and strains in the peri-implant bone tissue.

RESULTS

Upon establishing consistent osseointegration rates, the distribution of stress exhibited similarities across models with varying CIRs when subjected to vertical loads. However, when exposed to inclined loads, the maximum von Mises stress within the cortical bone escalated as the CIR heightened. Among both loading scenarios, notable escalation in the maximum von Mises stress occurred in the model featuring a CIR of 2.5 and an osseointegration rate of 25%. Conversely, other models displayed comparable strength. Notably, stress and strain values uniformly increased with augmented osseointegration across all models. Furthermore, an increase in osseointegration rate correlated with reduced maximum displacement for both cortical bone and implants.

CONCLUSIONS

After fixing osseointegration rates, the stress around shorter implants increased as the CIR increased under inclined loads. Thus, the effect of lateral forces should be considered when selecting shorter implants. Moreover, an implant failure risk was present in cases with a CIR ≥ 2.5 and low osseointegration rates. Additionally, the higher the osseointegration rate, the more readily the implant can achieve robust stability.

Effect of Antirotational Two-Piece Titanium Base on the Vertical Misfit, Fatigue Behavior, Stress Concentration, and Fracture Load of Implant-Supported Zirconia Crowns

This study investigated the effects of antirotational titanium bases on the mechanical behavior of CAD/CAM titanium bases used for implant-supported prostheses. The aim was to assess the impact on the marginal fit, fatigue behavior, stress concentration, and fracture load of implant-supported CAD/CAM zirconia crowns. Forty titanium implants were divided into two groups: those with antirotational titanium bases (ARs) and those with rotational titanium bases (RTs). Torque loosening and vertical misfit were evaluated before and after cyclic fatigue testing (200 N, 2 Hz, 2 × 10⁶ cycles). Fracture resistance was assessed using a universal testing machine (1 mm/min, 1000 kgf), and failed specimens were examined with microscopy. Three-dimensional models were created, and FEA was used to calculate stress. Statistical analysis was performed on the in vitro test data using two-way analysis of variance and Tukey's test (α = 0.5). Results show that the presence of an antirotational feature between the implant and titanium base reduced preload loss and stress concentration compared to rotational titanium bases. However, there were no differences in vertical misfit and resistance to compressive load.

Do Systemic Diseases and Medications Influence Dental Implant Osseointegration and Dental Implant Health? An Umbrella Review

The aim of this umbrella review is to evaluate what are the most common medications and systemic diseases that can affect bone-implant integration, the success rate and survival rate of dental implants, peri-implant tissue health, and implant loss. Systematic reviews, with meta-analysis or not, about how systemic diseases and medications influence dental implant osseointegration, survival rate, success rate, and peri-implant diseases, published only in the English language, are electronically searched across the most important scientific databases. The present umbrella review includes eight systematic reviews, and osteoporosis and diabetes are the most investigated pathologies. Systemic diseases, such as neurologic disorders, HIV, hypothyroidism, cardiovascular diseases, and drugs, such as beta blockers, anti-hypertensives, or diuretics do not show a decreased rate of implant osseointegration. It seems that drugs, such as proton-pump inhibitors (PPIs) or serotonin reuptake inhibitors (SSRIs), negatively affect implant osseointegration. Few studies compare the effects of drugs and systemic diseases on the parameters considered in this overview. It is important to underline how the results of this review need to be validated with subsequent and more reviews.

Finite element analysis in implant dentistry: State of the art and future directions

OBJECTIVE

To discuss the state of the art of Finite Element (FE) modeling in implant dentistry, to highlight the principal features and the current limitations, and giving recommendations to pave the way for future studies.

METHODS

The articles' search was performed through PubMed, Web of Science, Scopus, Science Direct, and Google Scholar using specific keywords. The articles were selected based on the inclusion and exclusion criteria, after title, abstract and full-text evaluation. A total of 147 studies were included in this review.

RESULTS

To date, the FE analysis of the bone-dental implant system has been investigated by analyzing several types of implants; modeling only a portion of bone considered as isotropic material, despite its anisotropic behavior; assuming in most cases complete osseointegration; considering compressive or oblique forces acting on the implant; neglecting muscle forces and the bone remodeling process. Finally, there is no standardized approach for FE modeling in the dentistry field.

SIGNIFICANCE

FE modeling is an effective computational tool to investigate the long-term stability of implants. The ultimate aim is to transfer such technology into clinical practice to help dentists in the diagnostic and therapeutic phases. To do this, future research should deeply investigate the loading influence on the bone-implant complex at a microscale level. This is a key factor still not adequately studied. Thus, a multiscale model could be useful, allowing to account for this information through multiple length scales. It could help to obtain information about the relationship among implant design, distribution of bone stress, and bone growth. Finally, the adoption of a standardized approach will be necessary, in order to make FE modeling highly predictive of the implant's long-term stability.

Occlusal contact and clearance of posterior implant-supported single crowns designed by two different methods: a self-controlled study

BACKGROUND

Precise occlusal design of implant-supported fixed prostheses is difficult to achieve by the conventional wax-up method, often requiring chairside adjustments. The computer-aided design (CAD) method is promising. This study aims to compare the occlusal contacts and clearance of posterior implant-supported single crowns designed by the CAD and conventional methods.

METHODS

Sample size calculation indicated fourteen samples per group. Two sets of type-IV plaster casts with a single implant analog inserted in the posterior teeth region were mounted as master casts in a mechanical articulator in maximal intercuspal position (MIP). Seven working cast sets were obtained from each master cast by a closed tray technique, and mounted in MIP. Two implant-supported single crowns were designed with an occlusal clearance to achieve light occlusal contact in each working cast set by CAD and conventional method, separately. For the CAD group, the crown was designed in digital models obtained by scanning the working casts. For the conventional group, wax-up of the crown was prepared on the working casts and scanned to generate a STL file. In the working and master casts, mean and minimum occlusal clearances in the designed occlusal contact area of the both finished prostheses were calculated using the occlusal clearance (OC) and occlusal record (OR) method. The prostheses' occlusion was evaluated in master casts.

RESULTS

For the evaluation in the working casts, both design methods had similar mean occlusal clearances by the OC method (195.4 ± 43.8 vs. 179.8 ± 41.8 μm; P = 0.300), while CAD group resulted in a significantly larger minimum occlusal clearance in the designed occlusal contact area (139.5 ± 52.3 vs. 99.8 ± 43.8 μm; P = 0.043). Both design methods had similar mean and minimum occlusal clearances by the OR method (P > 0.05). For the evaluation in the master casts, both design techniques had similar mean and minimum occlusal clearances, number and distribution of occlusal contacts, and lateral interference ratios (P > 0.05).

CONCLUSION

Occlusal contact and clearance of posterior implant-supported single crowns designed by the CAD method can be at least as good as those designed by the conventional wax-up method.

Bioengineering Applied to Oral Implantology, a New Protocol: “Digital Guided Surgery”

Rehabilitative dentistry has made enormous progress in recent years, not only due to the advent of new implant-prosthetic methods, but also thanks to new information technologies that support the doctor. This study aims to present a new implant protocol that involves the application of bioengineering methods. With the application of the finite element analysis, it is possible to evaluate the distribution of the forces of a fixture and possible implant rehabilitation on each patient, even before performing the surgery. This protocol provides for the combination of radiographic images and three-dimensional files to obtain predictable results on possible rehabilitation, guiding its planning in the best possible way. Surely, the evolution of machines and computers will enable the surgeon to carry out and maintain these protocols in a chair-side manner, and to carry out safe and predictable rehabilitations.

Advanced method of rehabilitating edentulous Jaws: A review of telescopic denture

BACKGROUND

Edentulism conducts to a recognized impairment of oral function with both aesthetic and psychological changes. These patients suffer from a multiplicity of problems with their dentures, such as insufficient stability, retention and pain during mastication. The rehabilitation of a part edentulous patient can be established using a wide range of prosthetic treatment options. The overdenture treatment uses a removable total denture that overlies retained teeth, tooth roots, or dental implants. In the literature it was shown that patients with removable overdentures supported and retained either by tooth roots or implants have more predictable prosthodontic outcomes.

OBJECTIVE

The aim of this review is to provide an overview on the overdenture with a focus on the tooth-supported telescopic overdenture.

METHODS

The literature research was performed in the Scopus, Web of Science, and Pubmed electronic databases. Document type was limited to papers written in English, without time restrictions. The Review was recorded in the international PROSPERO (International Prospective Register of Systematic Reviews) database with the following number CRD42022326415.

RESULTS

A total of 256 articles published were found from electronic searches, Two independent reviewers carried out the screening and the selection process for the studies. First, duplicate citations were eliminated. Then, the two Authors independently screened the retrieved articles by title and abstract of each citation to determine its suitability for inclusion. Finally, 13 full-text articles satisfied the inclusion criteria.

CONCLUSION

Prostheses supported by Frictional telescopic crowns offer an effective treatment alternative for patients with Severely reduced dentitions who do not want implant treatment or complete dentures.

Impact of bisphosphonate drugs on dental implant healing and peri-implant hard and soft tissues: a systematic review

Objective

Implantology represents the gold standard for oral rehabilitation, unfortunately, often, despite there are no local contraindications to this type of rehabilitation, there are uncertainties regarding the general health of our patients. Many patients nowadays take bisphosphonate drugs, often without first seeking advice from an oral surgeon or a dentist. The purpose of this review is precisely to highlight any contraindications to this type of treatment reported in the literature, in patients who take or have taken bisphosphonate drugs.

Methods

For this study the scientific information sources were consulted using as search terms “(“bisphosphonate AND “dental implant”)”, obtaining 312 results, these were subsequently skimmed according to the inclusion and exclusion criteria, and further evaluated their relevance to the study and the presence of requested outcomes.

Results

Only 9 manuscripts (RCTs, Multicentric studies and Clinical Trials) were included in this review, as they respected the parameters of this review, they were analyzed and it was possible to draw important results from them. Surely from this study it is understood that the use of bisphosphonate drugs does not represent an absolute contraindication to implant therapy, it is evident how adequate pharmacological prophylaxis, and an adequate protocol reduce the risks regarding implant failures. Furthermore, the values of marginal bone loss over time seem, even if not statistically significant, to be better in implant rehabilitation with bisphosphonate drugs association. Only a few molecules like risedronate, or corticosteroids, or some conditions like smoking or diabetes have shown a high risk of surgical failure.

Conclusion

Although this study considered different studies for a total of 378 patients and at least 1687 different dental implants, showing better results in some cases for dental implant therapy in cases of bisphosphonate intake, further clinical, randomized and multicentric studies are needed, with longer follow-ups, to fully clarify this situation which often negatively affects the quality of life of our patients and places clinicians in the face of doubts.

Finite Element Analysis of Zirconia Dental Implant

Titanium dental implants have had new competitors in recent years, such as fixtures made of zirconia, which promise better aesthetics. The purpose of this study is to evaluate their mechanical performance in silico (Finite Element Analysis). The investigation was performed on a single tooth Patent™ Dental Implant (Zircon Medical®, Altendorf, Switzerland) in two configurations: without offset (Test I) and with offset (Test II, 1.5 mm within the cortical bone). The Patent Implant system consists of two components: the implant with integrated abutment and the fibreglass post. The components of the dental implants were tested using a compression load of 400 N along the implant axis. The results showed that the chewing load generates stress distribution on the bone, therefore, the offset configuration should be avoided.

Mechanical response of different frameworks for maxillary all-on-four implant-supported fixed dental prosthesis: 3D finite element analysis

This study's purpose is to assess the stress distribution in the peri-implant bone, implants, and prosthetic framework using two different posterior implant angles. All-on-four maxillary prostheses fabricated from feldspathic-ceramic-veneered zirconia-reinforced lithium silicate (ZLS) and feldspathic-ceramic-veneered cobalt-chromium (CoCr) were designed with 17 or 30-degree-angled posterior implants. Posterior cantilever and frontal vertical loads were applied to all models. The distribution of maximum and minimum principal stresses (σmax and σmin) and von Mises stress (σVM) was evaluated. Under posterior cantilever load, with an increase in posterior implant angle, σmax decreased by 4 and 7 MPa in the cortical bone when ZLS and CoCr were used as a prosthetic framework, respectively. Regardless of the framework material, 17-degree-angled posterior implants showed the highest σVM (541.36 MPa under posterior cantilever load; 110.79 MPa under frontal vertical load) values. Regardless of the posterior implant angle, ZLS framework showed the highest σVM (91.59 MPa under posterior cantilever load; 218.99 MPa under frontal vertical load) values. Increasing implant angle from 17 to 30° caused a decrease in σmax values in the cortical bone. Designs with 30-degree posterior implant angles and ZLS framework material may be preferred in All-on-four implant-supported fixed complete dentures.

Prosthodontic Treatment in Patients with Temporomandibular Disorders and Orofacial Pain and/or Bruxism: A Review of the Literature

Temporomandibular disorders are a group of conditions affecting the temporomandibular joints, the jaw muscles, and related structures. Patients with temporomandibular signs and/or symptoms frequently present with indications for prosthetic treatment. The management of these patients aims to achieve patient comfort, occlusal stability, and the complex restoration of the teeth. The goal of this review is to provide an overview of the relationship between prosthodontics and temporomandibular disorders and/or bruxism with a focus on the cause-and-effect implications and the strategies for planning prosthetic treatments in patients with temporomandibular disorders and/or bruxism.

Passant Connection Screw of Dental Implants: An In Vitro SEM Preliminary Study

The use of dental implants in oral rehabilitations has become increasingly common, thanks to the safety and predictability of these rehabilitations. Unfortunately, dental implants, being alloplastic devices, are not free from biomechanical complications, especially in the case in which the connections are complex and involve several components. The aim of the study is to highlight what could be surface alterations using different screwing torques, or by repeating the screwing process several times. In this study, 40 passant screws (Osstem®, South Korea Dental Implant Ebony Gold®) were examined under a Zeiss EVO LS 10 scanning electron microscope (SEM), operating with an accelerating voltage of 20 kV. Passant screws were subdivided into 4 groups: 30 Nmm tightening torque; maximum tightening torque; 2 times 30 Nmm tightening torque; no screwing, new ones (control group). There are no significant differences in the surfaces of the passant screws in SEM images, and the 100% of the passant screws is free of defects or fractures. Surely, further studies and investigations will certainly be needed to allow improvement of these devices.

Prosthetic Surgical Templates and Dental Implant Site Time Preparation: An In Vitro Study

Numerous types of prosthodontics surgical guides, with and without metallic sleeves, have been found to be useful in clinical studies. The aim of this in vitro research was to compare the time required to complete the surgical procedure with two differently designed surgical prosthetic templates. Ten identical prototype models of mandible based on a CBCT and optical scan of a partially edentulous patient with missing teeth numbers 37, 46, and 47 were prepared and then printed. Five of these models were used for implant site preparation with a surgical guide without metal sleeves and dedicated surgical kit, and the other five models were used for the same procedure performed with a surgical guide with metal sleeves and a dedicated surgical kit. The time of implant site preparation was measured and recorded. Statistical analysis was performed using Student’s t-test for independent samples. Differences between groups were found to be statistically significant (t = −9.94; df = 28; p = 0.0000) with a lower value in favor of the surgical templates without metallic sleeves. Different types of prosthodontics surgical guides, with or without metallic sleeves, seemed to be an important factor which can significantly impact the time of implant site preparation and, therefore, the overall surgical procedure.

Intravascular Papillary Endothelial Hyperplasia of the Mandible: A Rare Entity

ABSTRACT

Intravascular papillary endothelial hyperplasia (IPEH) is a lesion characterized by the proliferation of endothelial cells within the lumen of the vessel, it was first described by Masson in 1923.The pathogenesis of Masson's tumor is still unknown, currently the most accredited hypothesis is the reactive 1. Clinically and symptomatologically it can have different presentations, it is, therefore, of fundamental importance to make a correct differential diagnosis. Diagnosis is mainly based on histological criteria. Intravascular papillary endothelial hyperplasia usually occurs in the skin and subcutaneous tissues, less commonly in the skeleton. The present is the fifth case of intravascular papillary endothelial hyperplasia of the mandible.

A cohort study on anticoagulant therapy risks in dental patients after multiple extractions

BACKGROUND

Due to technology and pharmaceutical science and increasing life expectancy, the patient population is continuously aging. Patients requiring dental extractions often have systemic and/or chronic diseases and are undergoing polypharmacologic therapy. Oral surgeons often interface with patients who perform anticoagulant therapy. The main aim of this study was to clarify what the contraindications and short-/long-term complications may be.

METHODS

A sample of 298 patients (mean age 58 years) who required multiple surgical dental extractions has been taken in consideration. Patients were divided into groups and subgroups according to the anticoagulant drug therapy.

RESULTS

Long-term complications represented variable bleeding between groups from 8 hours to 7 days after surgery. The One-Way ANOVA Test was used to compare the results between groups. Patients treated with direct oral anticoagulants showed fewer intraoperative problems, but further studies and further collaboration between doctors, cardiologists and oral dentists/surgeons are certainly needed to manage these patients in a predictable manner.

CONCLUSIONS

This study showed that using direct oral anticoagulants drugs results in few intraoperative bleeding, less postoperative hemorrhagic complications, and an easier administration of the drugs respect vitamin K antagonists, with mild and manageable complications.

The Application of the Divine Proportion for the Construction of the Visualized Treatment Objective in Craniofacial Surgery

ABSTRACT

Aesthetics and function of maxillofacial district are closely related and could interfere with patient psychological conditions. The aim of this paper is to describe and to analyze the procedures necessary for a proper surgical visualized treatment objective (VTO) realization through the use of the tracing on lateral head film, applying the divine proportion (or golden ratio) in certain steps. The method described is easy to realize, cheap and help both orthodontist and maxillo-facial surgeon to communicate each other and to the patients.For the following article, digital research and handheld research on surgical VTO planning for patients with skeletal or dentoalveolar severe deformities managed by surgeons and orthodontics were used. The research included articles in English published on dental and maxillofacial surgery journals.The surgical VTO consists of a "previsualization" of the objectives in order to make the desired changes for the individual patient. The result can thus be visualized and pre-evaluated rather than just imagined by the mind's eye. To simplify the procedure, the surgical VTO has been divided into 11 steps. The accurate model of the surgical result is fundamental in the treatment of dentofacial deformities. These predictions are intended to guide the treatment towards the desired result, to give the patient a reasonable preview of the outcome, and to ensure communication between the orthodontist and the surgeon.This technique proves to be effective in planning surgical treatment and it allows the clinician to view changes before, during, and after orthognathic surgery. The skeletal, dental, and aesthetic complete cephalometric evaluation is the key point to the long-term success of the results.

A Parametric Study on a Dental Implant Geometry Influence on Bone Remodelling through a Numerical Algorithm

To ensure the long-term success of a dental implant, it is imperative to understand how chewing loads are transferred through the implant prosthetic components to the surrounding bone tissue. The stress distribution depends on several factors, such as load type, bone–implant interface, shape and materials of the fixture and quality and quantity of the bone. These aspects are of fundamental importance to ensure implant stability and to evaluate the remodelling capacity of the bone tissue to adapt to its biomechanical environment. A bone remodelling algorithm was formulated by the authors and implemented by means of finite element simulations on four different implants with several design characteristics. Internal bone microstructure and density, apposition/resorption of tissue and implant stability were evaluated over a period of 12 months, showing the influence of the geometry on bone tissue evolution over time. Bone remodelling algorithms may be a useful aid for clinicians to prevent possible implant failures and define an adequate implant prosthetic rehabilitation for each patient. In this work, for the first time, external bone remodelling was numerically predicted over time.

Investigating inlay designs of class II cavity with deep margin elevation using finite element method

Background

This study evaluates the mechanical performance of deep margin elevation technique for carious cavities by considering the shape designs and material selections of inlay using a computational approach combined with the design of experiments method. The goal is to understand the effects of the design parameters on the deep margin elevation technique and provide design guidelines from the biomechanics perspective.

Methods

Seven geometric design parameters for defining an inlay’s shape of a premolar were specified, and the influence of cavity shape and material selection on the overall stress distribution was investigated via automated modelling. Material selection included composite resin, ceramic, and lithium disilicate. Finite element analysis was performed to evaluate the mechanical behavior of the tooth and inlay under a compressive load. Next, the analysis of variance was conducted to identify the parameters with a significant effect on the stress occurred in the materials. Finally, the response surface method was used to analyze the stress responses of the restored tooth with different design parameters.

Results

The restored tooth with a larger isthmus width demonstrated superior mechanical performance in all three types of inlay materials, while the influence of other design parameters varied with the inlay material selection. The height of the deep margin elevation layer insignificantly affected the mechanical performance of the restored tooth.

Conclusions

A proper geometric design of inlay enhances the mechanical performance of the restored tooth and could require less volume of the natural dentin to be excavated. Furthermore, under the loading conditions evaluated in this study, the deep margin elevation layer did not extensively affect the strength of the tooth structure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01630-z.

The New Elderly Patient: A Necessary Upgrade

The elderly individual is becoming the most common patient in clinical practice due to the increasing average life span, especially in developed countries. The current elderly patients are different from those of some decades ago. They usually have an active social life, want to be informed, and are actively involved in the current society with consequent high expectations for medical and dental treatment. However, not all the elderly patients are like this. Some of them show limited financial resources, reduced mental and manual skills, and poor motivation. The purpose of this communication is to make a brief characterization of the new elderly population in view of prosthetic and dental management.

1-Year Evaluation of OT Bridge Abutments for Immediately Loaded Maxillary Fixed Restorations: A Multicenter Study

Objective  Preliminary data on survival and success rates of immediately loaded, maxillary, screw-retained, implant-supported, fixed restorations delivered on narrow and low-profile OT Equator abutments (OT Bridge, Rhein’83) were evaluated.

Materials and Methods  This retrospective study evaluated data collected from patients rehabilitated with OT Bridge prosthetic concept between November 2017 and February 2019 in six different centers. Outcome measures were implant and prosthetic survival rates, biological and technical complications, marginal bone loss (MBL), oral health impact profile (OHIP), bleeding on probing, and plaque index.

Results  A total of 76 implants were inserted in 14 patients. Patients were followed for a mean period of 15.8 months (range = 12–24). All the patients receive OT Equator (Rhein'83) as intermediate abutments. One year after loading, one implant failed (1.3%). None of the prosthesis failed. One prosthetic complication was experienced in one patient. Three out of 76 implants were connected to the prosthetic framework using only the Seeger system, without screw. Difference in OHIP values was statistically significant (71.9 ± 8.5; p = 0.000). One year after loading, MBL was 0.21 ± 0.11 mm and p- value was 0.000. One year after loading, 8.7% of the examined implant sites present positive bleeding on probing, while 6.4% of the implant sites presented plaque.

Conclusion  The OT Equator abutments (Rhein'83) showed successful results when used to support maxillary fixed dental prosthesis delivered on four to six implants. High implant and prosthetic survival rates, very low complications, high patient satisfaction, and good biological parameters, including only 0.2 mm of bone remodeling were experienced one year after function. Further studies are needed to confirm these preliminary results.

Multicenter clinical trial on dental implants survival rate: a FDS76® study

BACKGROUND

Implantology, thanks to its predictability in oral rehabilitations, has become a widespread method for rehabilitating edentulous patients, offering excellent patient satisfaction. Improving the quality of oral health, especially if rehabilitation involves minimal short and long-term complications, leads to an improvement in the quality of life of our patients.

METHODS

This clinical study was conducted to evaluate the short and long-term complications (up to 18 months) of implant-prosthetic rehabilitations performed with a new dental implant (FDS76^®, Italy).

RESULTS

The results showed a limited number of complications or implant failures.

CONCLUSIONS

Knowing the latter could certainly help improve both surgical and dental materials performance.

Multicenter clinical trial on dental implants survival rate: a FDS76® study

BACKGROUND

Implantology, thanks to its predictability in oral rehabilitations, has become a widespread method for rehabilitating edentulous patients, offering excellent patient satisfaction. Improving the quality of oral health, especially if rehabilitation involves minimal short and long-term complications, leads to an improvement in the quality of life of our patients.

METHODS

This clinical study was conducted to evaluate the short and long-term complications (up to 18 months) of implant-prosthetic rehabilitations performed with a new dental implant (FDS76^®, Italy).

RESULTS

The results showed a limited number of complications or implant failures.

CONCLUSIONS

Knowing the latter could certainly help improve both surgical and dental materials performance.

Mineral Trioxide Aggregate Applications in Endodontics: A Review

A current topic in dentistry concerns the biocompatibility of the materials, and in particular, conservative dentistry and endodontics ones. The mineral trioxide aggregate (MTA) is a dental material with biocompatibility properties to oral and dental tissues. MTA was developed for dental root repair in endodontic treatment and it is formulated from commercial Portland cement, combined with bismuth oxide powder for radiopacity. MTA is used for creating apical plugs during apexification, repairing root perforations during root canal therapy, treating internal root resorption, and pulp capping. The objective of this article is to investigate MTA features from a clinical point of view, even compared with other biomaterials. All the clinical data regarding this dental material will be evaluated in this review article. Data obtained from the analysis of the past 10 years' literature highlighted 19 articles in which the MTA clinical aspects could be recorded. The results obtained in this article are an important step to demonstrate the safety and predictability of oral rehabilitations with these biomaterials and to promote a line to improve their properties in the future.

Occlusal Load Considerations in Implant-Supported Fixed Restorations

The advent of new technologies in the field of medicine and dentistry is creating improvements that lead clinicians to have materials and procedures able to improve patients’ quality of life. The aim of this article is to evaluate occlusion load and its consequences on fixed implant-supported prosthesis. New materials have granted clinicians the possibility achieve great aesthetic results in dental prosthesis, and new procedures allow them to standardize and give precise and repeatable results, especially for the functional and long-term stability aspects of products. Some principles should be carefully evaluated and applied to every dental prosthesis; the evaluation of the forces and fitting of meso-structures to dental implants, an aspect that is often not well considered by clinicians, is the main focus of this article.

A New Method of Measuring the Volumetric Change of Alveolar Bone Around Dental Implants Using Computed Tomography

This study proposes a method for measuring the volumetric change of alveolar bone after dental implant surgery using computed tomography (CT). A total of 40 implants in 20 patients (15 males and 5 females) were selected. The types of implants used were group 1: 24 CMI IS-II Active implants (Neobiotech Co., Seoul, Republic of Korea) and group 2: 16 SLActive Bone Level implants (Institut Straumann AG, Basel, Switzerland). The OnDemand3D software (CyberMed, Seoul, Korea) was used for analysis. The volumetric change of the alveolar bone around an implant fixture is measured as follows: (1) Establish two cylinders: the main cylinder with the implant axis as the central axis (radius of implant + 3 mm) and the error correction cylinder (radius of implant + 1 mm). (2) The height of the cylinder extended from the top of the fixture to a 3 mm coronal portion. (3) Calculate the volumetric change of the alveolar bone (Vd) by subtracting the volume of the error correction cylinder from the main cylinder between CT images taken immediately after the implant placement and 12 months later. After a one-year installation, the volumetric change of alveolar bone, ΔV (cc) had increased in both groups (group 1: −0.011 ± 0.015 cc, group 2: −0.012 ± 0.017 cc) with statistical significance (p < 0.05), and the difference between the groups was not statistically significant (p > 0.05). This three-dimensional assessment method would be a useful clinical reference for the assessment of marginal bone change after implant surgery.

3D Digital Impression Systems Compared with Traditional Techniques in Dentistry: A Recent Data Systematic Review

The advent of new technologies in the field of medicine and dentistry is giving improvements that lead the clinicians to have materials and procedures able to improve patients' quality of life. In dentistry, the last digital techniques offer a fully digital computerized workflow that does not include the standard multiple traditional phases. The purpose of this study is to evaluate all clinical trials and clinical randomized trials related to the digital or dental impression technique in prosthetic dentistry trying to give the readers global information about advantages and disadvantages of each procedure. Data collection was conducted in the main scientific search engines, including articles from the last 10 years, in order to obtain results that do not concern obsolete impression techniques. Elsevier, Pubmed and Embase have been screened as sources for performing the research. The results data demonstrated how the working time appears to be improved with digital workflow, but without a significant result (P = 0.72596). The papers have been selected following the Population Intervention Comparison Outcome (PICO) question, which is related to the progress on dental impression materials and technique. The comparison between dentists or practitioners with respect to classic impression procedures, and students open to new device and digital techniques seem to be the key factor on the final impression technique choice. Surely, digital techniques will end up supplanting the analogical ones altogether, improving the quality of oral rehabilitations, the economics of dental practice and also the perception by our patients.

Comparison of Four Implant-Supported Fixed Rehabilitation Options of the Edentulous Mandible: A 3D Finite Element Analysis

Aim:

This study aims to compare four implant-supported rehabilitation concepts of an edentulous mandible and determines the most biomechanically advantageous technique.

Materials and Methods:

Five models with four implants in different configurations were formed: four axial interforaminal implants, All-on-4 concept (two anterior axial and two posterior distally tilted implants), All-on-4v4 concept (four distally tilted interforaminal implants), All-on-4W (two anterior mesially tilted and two posterior distally tilted implants), and two axial interforaminal implants and two posterior extra-short implants. Straumann bone-level (4.1 × 12 mm) and tissue-level (4.1 × 4 mm) extra-short implants were used for this study. Spherical loadings from canine and molar regions were applied to evaluate tension, compression, and von Mises stresses by implementing 3D finite element analysis.

Results:

Among the alternative concepts, the classic All-on-4 and the All-on-4v4 techniques were the most successful treatment option in biomechanical terms. On the other hand, the use of extra-short implants in the posterior region was found to be the last method of choice. This was because of the high stresses on bones in most conditions, even though it balances the forces from the molar region on the implants.

Conclusion:

The results of the present study indicate that the classic All-on-4 and the All-on-4v4 techniques were the most successful treatment options in biomechanical terms for the rehabilitation of an edentulous mandible with four implant-supported fixed full-arch prostheses.

Dental occlusion and sport performance

INTRODUCTION

In recent years, interest has been given to the relationship between dental occlusion and athletes' performance. A correct occlusion allows for a correct position of the mandible in space and could be reached by wearing a splint made by a dentist. Achieving this condition appears to be an advantage for all athletes, and especially for those who have TMJ dysfunction. The purpose of the study was to investigate the hypothesis and common belief that correcting the occlusion or the use of a splint could improve an athlete's performance.

EVIDENCE ACQUISITION

A search on electronic database has been performed and obtained 141 results; then, following the application of the inclusion criteria, only 11 articles were selected.

EVIDENCE SYNTHESIS

A good occlusion seems to be an advantage for the athletes.

CONCLUSIONS

The use of an occlusal splint should be evaluated in different sports, because the occlusion and TMJ conditions of the athletes are different and the efforts in which they are subjected could not be generalized because the sports have various rules and characteristics that involves the stomatognathic system differently.

Bioengineering Methods of Analysis and Medical Devices: A Current Trends and State of the Art

Implantology, prosthodontics, and orthodontics in all their variants, are medical and rehabilitative medical fields that have greatly benefited from bioengineering devices of investigation to improve the predictability of clinical rehabilitations. The finite element method involves the simulation of mechanical forces from an environment with infinite elements, to a simulation with finite elements. This editorial aims to point out all the progress made in the field of bioengineering and medicine. Instrumental investigations, such as finite element method (FEM), are an excellent tool that allows the evaluation of anatomical structures and any facilities for rehabilitation before moving on to experimentation on animals, so as to have mechanical characteristics and satisfactory load cycle testing. FEM analysis contributes substantially to the development of new technologies and new materials in the biomedical field. Thanks to the 3D technology and to the reconstructions of both the anatomical structures and eventually the alloplastic structures used in the rehabilitations it is possible to consider all the mechanical characteristics, so that they could be analyzed in detail and improved where necessary.

We Do Not Eat Alone: Formation and Maturation of the Oral Microbiota

From the earliest moments of life, contact with the outside world and with other individuals invalidates the sterility of the oral cavity. The oral cavity passes from a sterility condition, that is present only during intrauterine life, to a condition in which a microbiota organizes and evolves itself, accompanying the person throughout their life. Depending on a patient’s age, systemic conditions and/or oral conditions, different characteristics of the oral microbiome are shown. By verifying and analyzing this process it is possible to understand what is at the basis of the etiopathogenesis of some oral pathologies, and also the function of the oral microbiome.

Endo and Exoskeleton: New Technologies on Composite Materials

The developments in the field of rehabilitation are proceeding hand in hand with those of cybernetics, with the result of obtaining increasingly performing prostheses and rehabilitations for patients. The purpose of this work is to make a brief exposition of new technologies regarding composites materials that are used in the prosthetic and rehabilitative fields. Data collection took place on scientific databases, limited to a collection of data for the last five years, in order to present news on the innovative and actual materials. The results show that some of the most commonly used last materials are glass fibers and carbon fibers. Even in the robotics field, materials of this type are beginning to be used, thanks above all to the mechanical performances they offer. Surely these new materials, which offer characteristics similar to those in humans, could favor both the rehabilitation times of our patients, and also a better quality of life.

Reliability of a Virtual Prosthodontic Project Realized through a 2D and 3D Photographic Acquisition: An Experimental Study on the Accuracy of Different Digital Systems

AIMS

The study aims to assess the accuracy of digital planning in dentistry, evaluating the characteristics of different intraoral 3D scanners and comparing it with traditional imaging 2D recording methods. Specifically, using computer aided design (CAD) software and measuring inside CAD software, authors want to verify the reliability of different models obtained with different techniques and machines.

METHODS

12 patients that needed aesthetic restorative treatment were enrolled in the study. All the patients underwent recording data of the height and width dental elements 1.1, 1.2, and 1.3 size using different technologies and comparing 2D with 3D methods. A T test was then applied in order to verify whether there was a statistically significant difference between the measurements obtained, comparing the different tools data (Emerald, TRIOS, Photogrammetry and DSS (Digital Smile System)) with the reference values.

RESULTS

No significant differences emerged in the measurements made with the different scanners (Trios 3Shape ®, Planmeca Emerald ®) and photogrammetry. Therefore, what should be underlined regarding the 2D measurements is the speed and simplicity compared to all 3D techniques, so this work can help to better define the field of application and the limits connected to 2D techniques, giving a good window of the technique.

CONCLUSIONS

The low number of patients is not sufficient to provide statistically significant results, but the digital planning future prospects seem to be promising. This study results highlighted how a photogrammetric scanner for dental arches would only have a much smaller shooting field size and greater accuracy. Despite these considerations, the photogrammetric facial scanner provided excellent results for the measurement of individual teeth, showing a great versatility of use.