This finite element analysis compared the biomechanical effects of different corticotomy approaches on tooth movement during maxillary canine retraction. 24 corticotomy models were designed varying the position, distance from the canine, and width of the cuts. The results showed that a distal corticotomy close to the canine resulted in the greatest canine displacement and lowest strain in the periodontal ligament, suggesting it may be the best approach for facilitating canine retraction. As the distance between the corticotomy and canine increased, its biomechanical effects on tooth movement decreased. The width of the cut did not significantly influence the results.
This journal club presents a case of prosthetic
rehabilitation of an amputated thumb. It emphasizes that
prosthetic replacement is a better option for aesthetic and
psychological improvement, particularly in cases where the
victim is unwilling to undergo complicated surgical procedures for reconstruction of thumb or where functioning
of thumb cannot be restored even by multiple surgeries. In
the present case, a 20 years old female patient, with
missing thumb of her right hand was rehabilitated aesthetically by a non-invasive and cost effective prosthetic
procedure by using heat temperature vulcanizing silicone
material. The prosthesis (the thumb) was attached using
medical adhesives. On 3 months recall appointment, no
complications were observed. The prosthesis was in good
shape and required no further intervention. The prosthetic
thumb lacks the sensation of a normal or reconstructed
thumb, although it does not require the multiple procedures
of surgical reconstruction and the accompanying loss of
time for rehabilitation and healing
Terminologies
Introduction
Implant treatment options at the extraction site
Timing for immediate implants
Indications of immediate implants
Contraindications of immediate implants
Advantages of immediate implants
Disadvantages of immediate implants
Rule of 5 triangles
Deciding factors for immediate implant treatment modality in extraction socket
Armamentarium required for atraumatic extraction
Jumping distance or critical space
Immediate implantation in the extraction socket of anterior maxilla
Immediate implantation in the extraction socket of anterior mandible
Immediate implantation in the extraction socket of multi-rooted posterior teeth
Clinical guidelines for esthetic outcomes when using immediate implant protocol.
Hard tissue changes after immediate implant placement
Soft tissue changes after immediate implant placement
Criteria and guidelines for immediate implant placement site
Risk and complication in immediate implant placement
Loading options for the immediately inserted implant
Survival and success rate of immediate implants
Recent advances: socket shield
Review of Literature
Conclusion
References
Immediate Placement and Provisionalization of Maxillary Posterior Single Impl...Abu-Hussein Muhamad
Functional immediate load is the most recent concept. This describes a load, within physiological limits, applied to implants before the osseo-integration process is completed. One of the treatment options offered to patients requiring replacement of one or more teeth is the use of prostheses supported by implants. Patients nowadays demand greater aesthetic and functional restorations; therefore, the clinician tries to reduce implant load time. All this leads to the implementation of several modifications to the conventional surgical and prosthetic protocol leading to a reduction in the load time of the implant. This is a case report of the immediate loading of posterior implant.
This journal club presents a case of prosthetic
rehabilitation of an amputated thumb. It emphasizes that
prosthetic replacement is a better option for aesthetic and
psychological improvement, particularly in cases where the
victim is unwilling to undergo complicated surgical procedures for reconstruction of thumb or where functioning
of thumb cannot be restored even by multiple surgeries. In
the present case, a 20 years old female patient, with
missing thumb of her right hand was rehabilitated aesthetically by a non-invasive and cost effective prosthetic
procedure by using heat temperature vulcanizing silicone
material. The prosthesis (the thumb) was attached using
medical adhesives. On 3 months recall appointment, no
complications were observed. The prosthesis was in good
shape and required no further intervention. The prosthetic
thumb lacks the sensation of a normal or reconstructed
thumb, although it does not require the multiple procedures
of surgical reconstruction and the accompanying loss of
time for rehabilitation and healing
Terminologies
Introduction
Implant treatment options at the extraction site
Timing for immediate implants
Indications of immediate implants
Contraindications of immediate implants
Advantages of immediate implants
Disadvantages of immediate implants
Rule of 5 triangles
Deciding factors for immediate implant treatment modality in extraction socket
Armamentarium required for atraumatic extraction
Jumping distance or critical space
Immediate implantation in the extraction socket of anterior maxilla
Immediate implantation in the extraction socket of anterior mandible
Immediate implantation in the extraction socket of multi-rooted posterior teeth
Clinical guidelines for esthetic outcomes when using immediate implant protocol.
Hard tissue changes after immediate implant placement
Soft tissue changes after immediate implant placement
Criteria and guidelines for immediate implant placement site
Risk and complication in immediate implant placement
Loading options for the immediately inserted implant
Survival and success rate of immediate implants
Recent advances: socket shield
Review of Literature
Conclusion
References
Immediate Placement and Provisionalization of Maxillary Posterior Single Impl...Abu-Hussein Muhamad
Functional immediate load is the most recent concept. This describes a load, within physiological limits, applied to implants before the osseo-integration process is completed. One of the treatment options offered to patients requiring replacement of one or more teeth is the use of prostheses supported by implants. Patients nowadays demand greater aesthetic and functional restorations; therefore, the clinician tries to reduce implant load time. All this leads to the implementation of several modifications to the conventional surgical and prosthetic protocol leading to a reduction in the load time of the implant. This is a case report of the immediate loading of posterior implant.
Crestal bone loss around dental implants after implantation of Tricalcium pho...Dr. Anuj S Parihar
Background and Aims: Bone loss around dental implants is generally measured by monitoring changes in marginal bone level using radiographs. After the first year of implantation, an implant should have <0.2 mm annual loss of marginal bone level to satisfy the criteria of success. However, the success rate of dental implants depends on the amount of the crestal bone around the implants. The main aim of this study was to evaluate and compare the crestal bone loss around implants placed with particulate β‑Tricalcium Phosphate Bone Graft and platelet concentrates. Methods: 50 individuals received hundred dental implants. Each individual received one dental implant in the edentulous site filled with β‑Tricalcium Phosphate Bone Graft along (β‑TCP) with Platelet‑ Rich Plasma (PRP)
(Group A) and another in edentulous site filled only with β‑Tricalcium Phosphate Bone Graft (Group B) in the posterior edentulous region. All the 100 implants were prosthetically loaded after a healing period of three months. Crestal bone loss was measured on mesial, distal, buccal and lingual side of each implant using periapical radiographs 3 months, 6 months and 9 months after implant placement. Results: The average crestal bone loss 9 months after the implants placement in Group A and Group B was 2.75 mm and 2.23 mm respectively, the value being statistically significant (P < 0.05). In both Group A and Group B, the average crestal bone loss was maximum on the lingual side followed by buccal, distal and mesial sides. Conclusion: β‑TCP is a promising biomaterial for clinical
situations requiring bone augmentation. However, the addition of PRP results in decreased bone loss around the dental implants.
In this study, Static structural analysis of a molar tooth was performed by using FEM. The commercial finite element package ANSYS version 14.5 was used for the solution of the problem. The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. Sometimes we are using artificial teeth instead of human molar tooth during broken. Here we optimize the molar teeth using different materials like acrylic, porcelain, silver and zirconia. Taking into consideration of forces acting on the top of the first molar teeth, the deformation, strain and stress are tabulated. And here we are studying about the molar teeth.
http://www.permadontics.com Dr. Berger and Dr. Aires are leading researchers in Dental implant technologies. Often lecturing and writing research papers for the industry and other doctors.
Atrophied Edentulous Mandible with Implant-Supported Overdenture; A 10-year f...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Immediate Implant Placement And Restoration With Natural Tooth In The Maxilla...Abu-Hussein Muhamad
Anterior tooth loss and restoration in the esthetic zone is a common challenge in dentistry today. The prominent visibility of the area can be especially distressing to the patient and requires a timely and esthetically pleasing solution. Immediate single-tooth implantation followed by immediate provisionalization is becoming an increasingly desirable treatment that offers numerous benefits over conventional delayed loading. Provisionalization for immediately-placed implants using the patient’s existing tooth can enhance the final aesthetic outcome if certain steps are
followed. If the natural tooth is intact and can be used as a provisional, the emergence profile can be very similar to the preoperative condition. This article outlines a technique to use the patient’s natural tooth after extraction to provisionalize an implant.
Abstract: Corticotomy-assisted orthodontic treatment is an established and efficient orthodontic technique that has recently been studied in a number of publications. Corticotomy facilitated orthodontics have been employed in various forms over speed up orthodontic treatment It involves selective alveolar decortication in the form of decortication lines and dots performed around the teeth that are to be moved. It is done to induce a state of increased tissue turnover and a transient osteopenia, which is followed by a faster rate of orthodontic tooth movement. This technique has several advantages, including faster tooth movement, shorter treatment time, safer expansion of constricted arches, enhanced post-orthodontic treatment stability and extended envelope of tooth movement. The aim of this article is to present a comprehensive review of the literature, including historical background, contemporary clinical techniques, indications, contraindications, complications and side effects. Keywords: Corticotomy, decortication, review, orthodontic treatment
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Crestal bone loss around dental implants after implantation of Tricalcium pho...Dr. Anuj S Parihar
Background and Aims: Bone loss around dental implants is generally measured by monitoring changes in marginal bone level using radiographs. After the first year of implantation, an implant should have <0.2 mm annual loss of marginal bone level to satisfy the criteria of success. However, the success rate of dental implants depends on the amount of the crestal bone around the implants. The main aim of this study was to evaluate and compare the crestal bone loss around implants placed with particulate β‑Tricalcium Phosphate Bone Graft and platelet concentrates. Methods: 50 individuals received hundred dental implants. Each individual received one dental implant in the edentulous site filled with β‑Tricalcium Phosphate Bone Graft along (β‑TCP) with Platelet‑ Rich Plasma (PRP)
(Group A) and another in edentulous site filled only with β‑Tricalcium Phosphate Bone Graft (Group B) in the posterior edentulous region. All the 100 implants were prosthetically loaded after a healing period of three months. Crestal bone loss was measured on mesial, distal, buccal and lingual side of each implant using periapical radiographs 3 months, 6 months and 9 months after implant placement. Results: The average crestal bone loss 9 months after the implants placement in Group A and Group B was 2.75 mm and 2.23 mm respectively, the value being statistically significant (P < 0.05). In both Group A and Group B, the average crestal bone loss was maximum on the lingual side followed by buccal, distal and mesial sides. Conclusion: β‑TCP is a promising biomaterial for clinical
situations requiring bone augmentation. However, the addition of PRP results in decreased bone loss around the dental implants.
In this study, Static structural analysis of a molar tooth was performed by using FEM. The commercial finite element package ANSYS version 14.5 was used for the solution of the problem. The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. Sometimes we are using artificial teeth instead of human molar tooth during broken. Here we optimize the molar teeth using different materials like acrylic, porcelain, silver and zirconia. Taking into consideration of forces acting on the top of the first molar teeth, the deformation, strain and stress are tabulated. And here we are studying about the molar teeth.
http://www.permadontics.com Dr. Berger and Dr. Aires are leading researchers in Dental implant technologies. Often lecturing and writing research papers for the industry and other doctors.
Atrophied Edentulous Mandible with Implant-Supported Overdenture; A 10-year f...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Immediate Implant Placement And Restoration With Natural Tooth In The Maxilla...Abu-Hussein Muhamad
Anterior tooth loss and restoration in the esthetic zone is a common challenge in dentistry today. The prominent visibility of the area can be especially distressing to the patient and requires a timely and esthetically pleasing solution. Immediate single-tooth implantation followed by immediate provisionalization is becoming an increasingly desirable treatment that offers numerous benefits over conventional delayed loading. Provisionalization for immediately-placed implants using the patient’s existing tooth can enhance the final aesthetic outcome if certain steps are
followed. If the natural tooth is intact and can be used as a provisional, the emergence profile can be very similar to the preoperative condition. This article outlines a technique to use the patient’s natural tooth after extraction to provisionalize an implant.
Abstract: Corticotomy-assisted orthodontic treatment is an established and efficient orthodontic technique that has recently been studied in a number of publications. Corticotomy facilitated orthodontics have been employed in various forms over speed up orthodontic treatment It involves selective alveolar decortication in the form of decortication lines and dots performed around the teeth that are to be moved. It is done to induce a state of increased tissue turnover and a transient osteopenia, which is followed by a faster rate of orthodontic tooth movement. This technique has several advantages, including faster tooth movement, shorter treatment time, safer expansion of constricted arches, enhanced post-orthodontic treatment stability and extended envelope of tooth movement. The aim of this article is to present a comprehensive review of the literature, including historical background, contemporary clinical techniques, indications, contraindications, complications and side effects. Keywords: Corticotomy, decortication, review, orthodontic treatment
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Corticotomy facilitated orthodontics
Although the art and science of orthodontics have progressed significantly over the past 100 years, relatively little has been done to enhance the rate at which tooth movement occur. Many methods have been done to enhance the rate of tooth movement. These methods include the injection of biologically active peptides, the use of magnets and even the application of electric current and corticotomy.
Corticotomy: is slight penetration through the cortical bone and did not be confused with the osteotomy. Or defined as incision made into the cortical bone.
This penetration or incision leads to decrease the resistance of the alveolar and diminish physical alveolar bone contact that accelerates the rate of tooth movement.
Several authors have described rapid tooth in conjunction with corticotomy surgery as movement by bony (Block). Kole6 was the first describe the corticotomy as a surgical procedure in which one tooth or group of teeth with the adjacent bone is repositioned in one step. But others prefer to call this osteo-corticotomy or intra alveolar segmental osteotomy, reserving the term corticotomy for a technique in which cuts are made in the buccal cortical plate of bone. So that the segment to be moved orthodontically is held only by cancellous trabeculea and palatal cortical bone.
Kole in 19596 reported combining orthodontics with corticotomy surgery and complete the active tooth movement in adult orthodontic cases in 6 to 12 weeks.
The inter-proximal corticotomy cuts were extended through the entire thickness of the cortical layer, just barely penetrating the medullary bone.
The vertical cuts were connected beyond the apices of the teeth with horizontal osteotomy cut extending through the entire thickness of the alveolus, essentially creating blocks of bone in which one or more teeth were embedded, using the crowns of the teeth as a handles. Kole believed that he was able to move the blocks of bone some what independly of each other because they were only connected by less-dense medullary bone. He found no incidence of root resorption, no loss of tooth vitality and no pocket formation.
Kole used this surgical technique for correction of some of dento-alveolar problems as:
Protruding of lower incisors: this procedure is indicated in most of cases but should be determined whether a mandibular or dento-alveolar retrusion. Buccally the cortiocotomy is performed between the incisors and canine then horizontal cut is made 1cm. below the incisors, lingual two vertical and one horizontal cut is made fig(1).
Distal displacement of a single tooth or group of teeth: correction necessitates a long period of treatment in adult patients fig(2) .
The retrusion of all six lower anterior teeth: after buccal and ligual corticotomy is perefrmed.
Alignment of rotated teeth.
Correction of spaced teeth: in maxillary and mandibular protrusion with diastemas between the t
FINITE ELEMENT ANALYSIS AND STATIC LOADING IN DENTAL IMPLANT WITH INNOVATIVE ...indexPub
Objective: The purpose of this study is to examine how different crown materials affect stress transformation and distribution around both dental implants. To do this, integrated and combined crowns were built, modelled, and tested under static axial loads using various material combinations. The biomechanical response was then examined. Methods: A validated three-dimensional finite element (FE) models of crown supported by implant was developed by to evaluate the effect of the different type of material (E max, zirconia, composite) on the short implant. After the FE models had been validated, simulations utilizing various configurations of various crowns fixed to two distinct types of implants were run and subjected to static loading to ascertain the distribution of stresses inside the bone around the implants. Result: The comparative results showed that manufacturing the crown using softer material (i.e., materials with lower elastic modulus) reduced the stress distribution in crown, implant and cancellous bone. It may refer to this phenomenon that softer material can absorb more energy from the applied compressive load, and result in transferring less energy to the implant and jaw bone. However, this effect was not significant on cortical bone compared to the cancellous bone. Combination of different materials for design and manufacturing the crown can alter the biomechanical response and could be beneficial for decreasing the stress distribution in implant and spongy region of jaw bone when stiffer material is needed to be covered in upper surface of the crown. In addition, the results suggests that shorter implant can increase the stress distribution in both cortical and cancellous bone. Conclusion: by using stiff material the stress will increase on the parts of implant and the surrounding bone which may led to failure of implant or bone resorption around of the implant, in other way by using less stiffer material the possibility of success will be increased and also the success rate of the implant is increased, also before deciding which implant size and length are used you select which type of the prosthetic will be used.
Periodontally Accelerated Osteogenic Orthodontics with Piezoelectric Surgery...Abu-Hussein Muhamad
Piezosurgery has been applied in dentistry for many years. This paper reviews specifically the treatment applications that have been used in surgically assisted orthodontic treatment since the last decade. Periodontally Accelerated Osteogenic Orthodontics (PAOO) is a surgical technique which results in an increase in alveolar bone width, shorter treatment time, increase post-treatment stability, and decrease amount of apical root resorption. The aim of this case report is to compare the use of micro-motor and piezoelectric surgery unit during decortication in Periodontally Accelerated Osteogenic Orthodontics technique.
Key words: Piezoelectric surgery, piezosurgery, Periodontal regeneration , accelerated tooth movement
Mandibular arch form the relationship between dental and basal anatomyEdwardHAngle
We investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form.
Orthodontics has been developing greatly in achieving the desired results both clinically and technically.
Today, it is still very challenging to reduce the duration of orthodontic treatments.
It is one of the common deterents that the orthodontist faces and it causes irritation among adults plus increasing risks of caries, gingival recession, and root resorption.
A number of attempts have been made to create different approaches both preclinically and clinically in order to achieve quicker results, but still there are a lot of uncertainties and unanswered questions towards most of these techniques.
Over time, progressively shorter implants have been placed such that short implants are now available that are less than 6 mm in length. The viability and high success rates seen with short implants can be explained by osseointegration, the macro geometric design of the implant, as well as physics and the distribution of forces. This paper was aimed to review the stability and survival rate of short implants under functional loads. Numerical and clinical studies were reviewed. Keywords: Short dental implants, sinus augmentation, factors affecting bone regeneration in dental implantology
“One-Piece” Immediate-Load Post-Extraction Implant In Maxillary Central IncisorAbu-Hussein Muhamad
Abstract: This case report describes extraction of a fractured left maxillary central incisor tooth, followed by immediate placement of an one-piece implant in the prepared socket and temporization by a bonded restoration.
Materials And Methods: The tooth was extracted with minimal hard and soft tissue trauma and without flap reflection. The socket was prepared to the required depth and a Implant was inserted.
Results: The atraumatic operating technique and the immediate insertion of the one-piece Implant resulted in the preservation of the hard and soft tissues at the extraction site.
Conclusion: The “One-piece” dental implant and provisional restoration provided the patient with immediate esthetics, function, comfort and most importantly preservation of tissues. The one-piece implant design resulted in a high cumulative implant survival rate and beneficial marginal bone levels.
Atrophied Edentulous Mandible with Implant-Supported Overdenture; A 10-year f...Abu-Hussein Muhamad
Abstract: Severe atrophy of the inferior alveolar process and underlying basal bone often results in problems with a lower denture. These problems include insufficient retention of the lower denture, intolerance to loading by the mucosa, pain, difficulties with eating and speech, loss of soft-tissue support, and altered facial appearance. These problems are a challenge for the prosthodontist and surgeon. In this case report, patient with resorbed edentulous mandible was successfully rehabilitated using two dental implants placed in the interforaminal region with ball abutments opposing conventional maxillary complete denture. Key Words: dental implants; dental prosthesis, implant-supported; resorption,
Once novel, Invisalign is now a digital orthodontic appliance used to treat millions of patients. This customized appliance is created by the aid of sophisticated 3D imaging and animation tools that enable virtual simulation of tooth movements. Tooth movements resemble a filmstrip, and each frame is called a stage. Each stage corresponds to a set of clear plastic aligner trays. As the trays are worn by the patient, every tray pushes the teeth 0.25-0.33mm at a time (Tuncay 2006). Each tray or aligner is composed of clear, removable polyurethane, which provides esthetic and more comfortable appliance wear experience than the traditional fixed appliances. This unique and esthetic alternative to tooth movement continues to recruit more patients to orthodontic therapy.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
1. Biomechanical effects of corticotomy approaches
on dentoalveolar structures during canine
retraction: A 3-dimensional finite element
analysis
Chongshi Yang,a
Chao Wang,b
Feng Deng,c
and Yubo Fand
Chongqing and Beijing, China
Introduction: Corticotomy has proven to be effective in facilitating orthodontic tooth movement. There is,
however, no relevant study to compare the biomechanical effects of different corticotomy approaches on tooth
movement. In this study, a series of corticotomy approaches was designed, and their impacts on dentoalveolar
structures were evaluated during maxillary canine retraction with a 3-dimensional finite element method.
Methods: A basic 3-dimensional finite element model was constructed to simulate orthodontic retraction of
the maxillary canines after extraction of the first premolars. Twenty-four corticotomy approach designs were
simulated for variations of position and width of the corticotomy. Displacement of the canine, von Mises
stresses in the canine root and trabecular bone, and strain in the canine periodontal ligament were calculated
and compared under a distal retraction force directed to the miniscrew implants. Results: A distal corticotomy
cut and its combinations showed the most approximated biomechanical effects on dentoalveolar structures
with a continuous circumscribing cut around the root of the canine. Mesiolabial and distopalatal cuts had a
slight influence on dentoalveolar structures. Also, the effects decreased with the increase of distance between
the corticotomy and the canine. No obvious alteration of displacement, von Mises stress, or strain could
be observed among the models with different corticotomy widths. Conclusions: Corticotomies enable
orthodontists to affect biomechanical responses of dentoalveolar structures during maxillary canine retraction.
A distal corticotomy closer to the canine may be a better option in corticotomy-facilitated canine retraction.
(Am J Orthod Dentofacial Orthop 2015;148:457-65)
T
wo main challenges are often confronted in
orthodontic treatment for adult patients: long
duration and risk of side effects such as root
resorption and marginal bone loss.1,2
To cope with
these problems, surgical techniques are used to
facilitate orthodontic tooth movement, including
alveolar osteotomy, corticotomy, and distraction
osteogenesis.3-5
Compared with osteotomy and
distraction osteogenesis, corticotomy has become
popular gradually because of the minor surgical injury,
flexible approach, and operational simplicity.
Corticotomy has been demonstrated to facilitate
orthodontic tooth movement effectively in the clinic. It
has many advantages over more traditional orthodon-
tics, including reduced orthodontic treatment time,
more significant tooth movement, and less anchorage
required.5,6
Wilkco et al5
attributed these effects of
corticotomy to the regional acceleration phenomenon,
which is characterized by an increase in the rate of
bone turnover. The remodeling of alveolar bone and
periodontal ligament (PDL) would be activated and
aggravated after being exposed to an insult such as a
corticotomy or a cortical perforation. En-block
a
Graduate student, Chongqing Key Laboratory of Oral Diseases and Biomedical
Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing,
China.
b
Assistant professor, Chongqing Key Laboratory of Oral Diseases and Biomedical
Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing,
China.
c
Professor, Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences,
Stomatological Hospital of Chongqing Medical University, Chongqing, China.
d
Professor, Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences,
Chongqing Medical University, Chongqing; professor, Key Laboratory for Biome-
chanics and Mechanobiology of Chinese Education Ministry, International
Research Center for Implantable and Interventional Medical Devices, Beihang
University, Beijing, China.
Funded by the National Natural Science Foundation of China (numbers
11421202 and 11120101001).
Address correspondence to: Yubo Fan, Stomatological Hospital of Chongqing
Medical University, No. 426, Yubei District, Chongqing, China; e-mail,
yubofan@buaa.edu.cn.
Submitted, September 2014; revised and accepted, March 2015.
0889-5406/$36.00
Copyright Ó 2015 by the American Association of Orthodontists.
http://dx.doi.org/10.1016/j.ajodo.2015.03.032
457
ORIGINAL ARTICLE
2. movement of the bone segment was another
explanation for this technique.7,8
Corticotomy can
reduce the resistance of alveolar bone to orthodontic
tooth movement by breaking the continuity of the
bone layer, leading to a bone-bending effect,
and possibly even a greenstick fracture of the alveolar
bone.9
Orthodontic tooth movement is the result of
remodeling of the alveolar bone and the PDL around
the tooth.10
Two stages are included in this procedure:
the delivery of orthodontic force and the biologic
responses to the force.11
The force generated by the
orthodontic appliance is transmitted to the PDL by the
teeth and then to surrounding alveolar bone,
contributing to the change of the mechanical
environment of the dentoalveolar structure. The
mechanical stimulation can trigger a series of biologic
responses to regulate the deposition or resorption of
the alveolar bone temporarily and spatially to facilitate
tooth movement. The internal strength and distribution
of the mechanical stimulation can be denoted accurately
with stress and strain, rather than with orthodontic
force, in consideration of the shape and size of the den-
toalveolar units.12
The stress and strain in dentoalveolar
structure can be altered by breaking the continuity of the
cortical bone after a corticotomy.13
The change of stress
or strain can be calculated using 3-dimensional (3D)
finite element methods.
Three-dimensional finite element analysis is a
numeric technique for simulating mechanical processes
of a real physical system; it is considered to be a valid
and reliable approach for calculating stress, strain, and
displacement of dentoalveolar structures.14,15
This
technique can be used to simulate orthodontic
processes with different treatment plans and to
compare their biomechanical effects without
increasing the numbers of patients or animals in the
sample, unlike clinical or animal investigations.
The routine treatment plan for patients with
maxillary or bimaxillary protrusion is retraction of the
anterior teeth after extraction of the premolars. With
regard to these patients, a 2-step treatment can be
used to make the canine move first during space
closure.16
To shorten the treatment time and save
anchorage, corticotomies have been used to facilitate
canine movement in the clinic.17,18
Although these
studies have provided useful findings, the corticotomy
approach was limited. More importantly, little research
regarding the biomechanical effects of corticotomy
approaches on dentoalveolar structures has been done.
Therefore, the aims of this study were to design
different corticotomy approaches and compare their
biomechanical impacts on dentoalveolar structures
during retraction of the maxillary canine and to select
an optimal approach for clinical adoption.
MATERIAL AND METHODS
Construction of the basic finite element model was
based on computed tomography scans (120 kV;
175 mA; slice thickness, 0.625 mm) (LightSpeed VCT;
GE Healthcare, Wauwatosa, Wis) of the skull of an
adult with maxillary protrusion. A surface 3D model of
the maxillary alveolar bone and the dentition with the
first premolars extracted was constructed from the
scanned images through thresholding, region growing,
and calculating 3D operations with Mimics software
(version 9.0; Materialise, Leuven, Belgium). Scaling
and Boolean operations were performed on the surface
model of the alveolar bone and dentition to generate
the cortical bone with an average thickness of 2.0 mm
and the PDL around the tooth with an average thickness
of 0.2 mm based on the studies of Wang et al14
and Lim
et al19
with Rapidform software (version 6.5; INUS,
Seoul, Korea). The orthodontic appliances, including
edgewise brackets for the anterior teeth and premolars,
buccal tubes for the molars, square wires, and miniscrew
implants, were designed and modeled according to
clinical applications in computer-assisted design
software (version 2011; Solidworks, Velizy-Villacoublay,
France). The brackets and buccal tubes were placed on
the center of the labial or buccal surface of the clinical
crown of the teeth. The implants were placed in the
interradicular space between the first molar and the
second premolar. All components were saved in initial
graphics exchange specification format and imported
into Abaqus (version 6.11; Solidworks). The bases of
the brackets and buccal tubes were subtracted from
the corresponding teeth to create a matching geometry.
Then the alveolar bone, teeth, PDL and orthodontic
appliances were assembled to form the geometric model.
Volumetric meshes of these components in the model
were created separately. The types and numbers of
elements and nodes are listed in Table I
The first step of simulation of the corticotomy
approach was to design and build a shear band
Table I. Types of elements and numbers of nodes and
elements
Types of element Nodes (n) Elements (n)
Teeth C3D4 34037 166707
PDL C3D20R 589521 140402
Trabecular bone C3D4 29405 139600
Cortical bone C3D10 79619 40356
Bracket C3D4 28097 116846
Square wire C3D8R 1233 540
458 Yang et al
September 2015 Vol 148 Issue 3 American Journal of Orthodontics and Dentofacial Orthopedics
3. corresponding to the approach in Solidworks. Then
cortical bone was subtracted by the shear band to
generate the model in Abaqus. Twenty-four models
were built in this study. These models can be classified
as follows.
For the corticotomy approaches with the position of
the cuts varied, the corticotomy cuts were in cortical
bone around the maxillary canine. There were 4
basic cuts: mesiolabial, mesiopalatal, distolabial, and
distopalatal. Other approaches were the various
combinations of these cuts and combinations with labial
and palatal cuts. There were 20 corticotomy approaches
designed and modeled (Fig 1).
For the corticotomy approaches with the distance to
the canine varied, 2 other cuts parallel to the distal
corticotomy were designed at the extraction side. They
were 2 and 4 mm from the distal corticotomy cut,
respectively (Fig 1).
For the corticotomy approaches with the width of the
corticotomy cut varied, the width of the corticotomy cuts
above was set at 0.4 mm according to the diameter of the
bur used for corticotomies in the clinic. Two other cuts
with widths of 0.6 and 0.8 mm were designed on the
base of the distal corticotomy cut (Fig 1).
Five materials were used in this study. All materials
were assumed to be homogeneous, isotropic, and
linearly elastic. The material properties were determined
from the values documented in the literature (Table II).
Then the material properties were assigned to cortical
bone, trabecular bone, teeth, PDL, and orthodontic
appliances.
Canine distalization is the first step of space closure
in a 2-step treatment. To eliminate the complex
constraints of square wire on the canine and to facilitate
its movement, the segmented arch technique was used
in this study. The maxillary incisors, ipsilateral molars,
and second premolars were connected with 3 pieces of
square wire. The bilateral canines were not tied to the
Fig 1. Designs of corticotomy approaches for the maxillary canine: A, B, and C, continuous
circumscribing cut around the canine from the labial, lingual, and occlusal views; D, definition of canine
position for the designs of corticotomy approaches below; E, corticotomy approaches with the positions
of the cuts varied; F, corticotomy approaches with the distance to the canine varied; G, corticotomy
approaches with the width of the corticotomy cut varied.
Table II. Material properties
Young's
modulus (MPa)
Poisson's
ratio Reference
Cortical bone 10.7E3 0.3 Aversa et al20
Trabecular bone 9.7E2 0.3 Aversa et al20
Teeth 20.7E3 0.3 Lee and Baek21
PDL 50 0.45 Lin et al22
Brackets and stainless
steel wire
200E3 0.3 Canales et al23
American Journal of Orthodontics and Dentofacial Orthopedics September 2015 Vol 148 Issue 3
Yang et al 459
4. square wire to let them move freely. To prevent
separation and slippage, binding constraints were
used to define these interfaces: square wire-bracket,
tooth-bracket, PDL-tooth, trabecular bone-PDL, and
cortical bone-trabecular bone. The miniscrew implants
were not involved in calculations of finite element
models, and they were used to indicate the direction of
the orthodontic load (Fig 2).
All these models were restrained at the nodes on the
maxillary bone at the base of nasal cavity in all degrees of
freedom. To simulate retraction of the maxillary canine,
a 100-cN concentrated force was applied to the middle
points of the bracket slot toward the crown notch of
the miniscrew implant according to the clinical
condition (Fig 2). The displacement of the canine, stress
distributions in the canine root, and strain distributions
in the PDL and the trabecular bone were analyzed with
Abaqus software.
RESULTS
The displacements of the canines were observed in a
newly defined coordinate system: origin-anterior nasal
spine; x-axis, the line through posterior nasal spine;
and the x-y plane–middle sagittal plane. The initial
displacement of the canine showed distal movement
combined with clockwise rotation, and the largest
displacement of the canine was highly concentrated on
the cusp in all models (Fig 3). The position of the
corticotomy had an obvious effect on the displacement
of the canine. The maxillary canine in the model with
the continuous circumscribing cut showed the greatest
displacement, and larger displacements were found in
models with distal corticotomy cuts and their
combinations. However, no notable difference of canine
displacement was observed in models with distopalatal
and mesiolabial cuts and in the model with no
corticotomy. As the distance between the canine and
the corticotomy increased, the displacement of the
canine decreased gradually. The width of the
corticotomy cut had no obvious influence on the canine
displacement (Fig 3).
The von Mises stress distribution in the canine root is
illustrated in Figure 4. The maximum von Mises stress
was centered on the distolabial side of the cervix in all
models. The position of the corticotomy cuts had similar
variations on the distribution of the von Mises stresses to
the distribution of displacements of the canine. When
the distance and the width of the corticotomy cut were
increased, the maximum stress value was reduced,
especially for a corticotomy with the distance
increased. In general, the differences of the maximum
stress in the canine roots were not evident among these
models.
The maximum strain was concentrated mainly in the
cervical region of the PDL (Fig 5). There were significant
differences in the strain values in the PDL with the
changes of corticotomy position. The maximum strain
values decreased in the models with the continuous
circumscribing cut and the distal cut and its
combinations, but the values were enhanced in the
models with the mesial cut and its combinations
compared with the model with no corticotomy. The
maximum strain in the PDL increased gradually when
the distance to the canine increased. The influence of
the farthest corticotomy, which was about 5 mm from
the canine, got close to the effect with no corticotomy.
The width of the corticotomy had no remarkable
influence on the strain distribution in the PDL of the
canine.
von Mises stress in the trabecular bone was mainly
concentrated on the alveolar crest at the distal side of
the canine in the model without a corticotomy. But in
models with a corticotomy, the area of stress
concentration transferred to the alveolar crest near the
corticotomy. Thus, the position of the corticotomy can
affect the distribution of stress in trabecular bone
remarkably. The trabecular bone showed the maximum
stress value in the model with a continuous
circumscribing corticotomy cut, a lower stress value in
the model with the distal corticotomy cut and its combi-
nations, and still a lower stress value in the models with
mesial and minor cuts. When the distance between the
Fig 2. Basic geometric model and illustration of the boundary and load: A, frontal view; B, lateral view.
Diamonds, Boundary; arrow, orthodontic load.
September 2015 Vol 148 Issue 3 American Journal of Orthodontics and Dentofacial Orthopedics
460 Yang et al
5. corticotomy and the canine increased, the maximum
stress value was reduced. No obvious alteration of the
stress distributions was observed among the models
with different corticotomy widths (Fig 6).
DISCUSSION
The continuous circumscribing cut around the root
of the tooth proposed by Wilkco et al5
was reported in
many studies, and its effect on facilitating tooth
movement has been confirmed.18,24
In this approach, 4
vertical and 2 horizontal cuts around the root need to
be made after elevation of the full-thickness
mucoperiosteal flap, as for the canine. Although this
technique proved to be effective in shortening treatment
time, it was difficult for most orthodontic patients to
accept because of its postoperative discomfort and risk
of complications. To reduce the surgical injury and the
difficulty of the operation, new corticotomy approaches
with minor cuts were designed by changing the
continuous circumscribing cut in this study. The
biomechanical effects of these approaches on
dentoalveolar structures were studied and compared
with the models with the continuous circumscribing
corticotomy and with no corticotomy. At the same
time, we also considered the distance between the
corticotomy and the canine, and considered the width
of the corticotomy cut in this study.
Because of the deviations between the finite element
models and the actual situation in geometric and
mechanical similarities, and owing to material property
and boundary conditions, the results of this study should
be interpreted with caution. For instance, the PDL was
assumed to be isotropic, homogeneous, and linearly
elastic in this study, but the PDL is a nonlinear,
viscoelastic, and anisotropic material.25
Meanwhile, the
thickness of the PDL was set at 0.2 mm, and the
thickness of cortical bone was set at 2.0 mm. However,
the PDL and the cortical bone are not uniform in
thickness.26,27
In addition, it is difficult to simulate the
real situation of alveolar sockets after the extraction of
teeth. Because the healing of an alveolar socket is a
dynamic process, the morphology and mechanical
characteristics of alveolar bone in this area change
markedly. Therefore, the alveolar sockets were
excluded in these finite element models, and the
height and width of the alveolar process at the
Fig 3. Comparison of the maximum initial displacements of the canine in the models: A, with the
position of corticotomy cut varied; B, with the distance between the corticotomy cut and the canine
varied; C, with the widths of corticotomy varied; D, distribution of the initial displacements of the canine.
American Journal of Orthodontics and Dentofacial Orthopedics September 2015 Vol 148 Issue 3
Yang et al 461
6. extraction site were decreased slightly. Canine
movement occurred after the socket was well healed in
this study. Nevertheless, for comparisons, the relative
results have more value than the absolute results. In
this study, the different biomechanical responses of
the dentoalveolar structures with corticotomy
approaches were observed, and influences of these
approaches on orthodontic canine distalization were
seen.
Several studies have been published about the impact
of acceleration of canine movement and the histologic
findings. Aboul-Ela et al17
evaluated the clinical effects
of corticotomy-facilitated orthodontics during maxillary
canine retraction. Their results showed that the rate of
canine retraction with corticotomy was about twice
that of the control side in the first 2 months. Kim
et al28
investigated the biologic effects of corticotomy
on alveolar remodeling during canine retraction in an
animal study. Their histomorphometric analysis showed
an extensive direct resorption of bundle bone with less
hyalinization. Many researchers have attributed these
effects to the regional acceleration phenomenon, where
the acceleration of bone turnover was observed through
animal research.29,30
These studies confirmed the effects
of corticotomy as a stimulating factor that can increase
the rate of bone turnover. The change of the mechanical
situation in alveolar bone may be another stimulating
factor that can strengthen the remodeling of alveolar
bone, leading to rapid canine movement, which has
been proven in previous studies.31,32
In this study, we
found that the mechanical responses of dentoalveolar
structures can be affected by a corticotomy; the
responses were mainly reflected in the stress in
the trabecular bone. The maximum stress value in the
model with the continuous circumscribing cut
increased several times in the alveolar bone near the
corticotomy compared with the model with no
corticotomy.
The maximum displacement of the canine was
concentrated on the cusp of its crown under an
Fig 4. Comparison of the maximum stresses in the canine roots in the models: A, with the position of
the corticotomy cut varied; B, with the distance between the corticotomy cut and the canine varied;
C, with the widths of the corticotomy varied; D, distribution of the von Mises stress in the canine root
from the labial and distal views.
September 2015 Vol 148 Issue 3 American Journal of Orthodontics and Dentofacial Orthopedics
462 Yang et al
7. orthodontic load directed to the miniscrew implant. This
result demonstrated that the canine had clockwise
rotation, since the orthodontic force did not pass the
resistance center of the canine. This result is consistent
with the results reported by Xue et al.13
Alveolar bone
on the distolabial side of the canine was the main source
of resistance to its movement when the canine showed
clockwise rotation. Therefore, the maximum stress in
the canine root was focused on its cervix at the
distolabial side.
The effect of accelerated tooth movement and the
safety of the periodontal tissues are primary concerns
when performing a corticotomy. Changes of strain in
the PDL may have a significant influence on orthodontic
tooth movement. For one thing, the PDL is thought to be
the medium of orthodontic force transfer. For another,
the PDL itself takes part in the reactions promoting
orthodontic tooth movement.33
In this study, the distal
corticotomy approach and its combinations can reduce
the strain value of the PDL of the canine, but a mesial
corticotomy and its combinations can increase the strain
value. This result may contribute to the lower the rate of
orthodontic external root resorption, according to
Viecilli et al.12
In these models with different corticotomy
approaches, the model with the continuous circumscrib-
ing cut around the root of the canine affected the
mechanical responses of dentoalveolar structures the
most, and the distal corticotomy and its combinations
had similar impacts with the continuous circumscribing
cut compared with the model with no corticotomy.
These results can be generalized as to how corticotomy
cuts can greatly reduce the resistance to tooth move-
ment and how corticotomy cuts can affect the mechan-
ical responses of dentoalveolar structures greatly.
Therefore, a distal corticotomy approach may be a better
alternative to continuous circumscribing, and it can be
accepted readily by patients because of its minor injury
to dentoalveolar structures. A corticotomy cut closer to
the canine may benefit its distalization more because
the impact of the corticotomy decreased with the
increased distance between the cut and the canine.
Fig 5. Comparison of the maximum strains in the PDL of canine in the models: A, with the position
of the corticotomy cut varied; B, with the distance between the corticotomy cut and the canine varied;
C, with the widths of the corticotomy varied; D, distribution of strains in the PDL of the canine from the
labial and distal views.
American Journal of Orthodontics and Dentofacial Orthopedics September 2015 Vol 148 Issue 3
Yang et al 463
8. CONCLUSIONS
In this study, 24 corticotomy approaches used for
facilitating canine distalization were designed and
simulated, taking into consideration position, distance,
and width of the corticotomy. The biomechanical
responses of dentoalveolar structures were analyzed
and compared with 3D finite element analysis. From
the results of this study, the following conclusions can
be drawn.
1. Corticotomy surgery can influence the mechanical
responses of dentoalveolar structures during
maxillary canine retraction.
2. The position of the corticotomy can affect the
mechanical responses of dentoalveolar structures.
A distal corticotomy has similar biomechanical
effects as a continuous circumscribing cut around
the root of the canine.
3. When the distance between the corticotomy cut and
the canine increased, the biomechanical effects of
the corticotomy decreased gradually.
4. A distal corticotomy closer to the canine may be a
better option for rapid canine retraction, taking
into account of its biomechanical effects and
surgical injury.
SUPPLEMENTARY DATA
Supplementary data related to this article can
be found online at http://dx.doi.org/10.1016/j.ajodo.
2015.03.032
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