DentistryUnited.com Newsletter

 


                    D e n t a l    F o l l i c l e               

             The        Monthly     E-newsletter                   Vol - I       Number- IX             February 2007

In this Issue:

  • Editorial

  • News

  • Laughter the best Medicine

  • Evaluation of the efficacy of a collagen GBR membrane (BioMend Extend) supported by autogenous bone grafts,     for the treatment of peri-implant bony defects, during implant placement."Part I - Dr.Yousef Abd ElGhaffar

  •  RASHA RECOMMENDS  - Dr. Rasha Seragelden

  • Career Options in Dentistry - Dr.Vinayak Joshi

  • Could what we see in our CLINICS be EVIDENCE?! - Dr. Maziar Mir

 

Editorial :

      Dear Fellow Dentist,

                           We are now in the ninth month since the inception of Dental Follicle! In this short span , we have reached almost every corner of the world! Day by day the number of subscribers are increasing! You can contribute to your own Dental Follicle's success by inviting your friends to use the free subscription !

                             Dr. Rasha Seragelden joined us in December , Dr Maziar Mir in January and  now , February , one more stalwart joins us to share his knowledge; Dr.Yousef Abd ElGhaffar , from University of Cairo , Egypt.We plan to make Dental Follicle the most intellectually sound newsletter for  dentists across the globe and infact this is the first of its kind where in we have dentists coming from across the globe to share their knowledge on a common platform!

                              Yahoo groups is growing day by day with the latest discussion going on on Lasers! If you are still not a part of DentistryUnited in Yahoo ,click on the icon below.

Click here to join DentistryUnited
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Yours truly

Dr.S. Nabeel

Editor of Dental Follicle & WebMaster www.DentistryUnited.com

News :

         

                       

Laughter The Best Medicine :

A young dentist had just opened his clinic and felt really excited. His secretary told him a man was there to see him. The young doctor told her to send him in.
Pretending to be a busy dentist, he picked up the phone just as the man came in. "Yes, that's right. The fee is  400$. Yes, I'll expect you ten past two. Alright. No later. I'm very busy man"
He Hung up and turned to man waiting. "May I help you?"
"No," Said the man," I just came in to install the phone"

                                                              

 

                                                                   

Evaluation of the efficacy of a collagen GBR membrane (BioMend Extend) supported by autogenous bone grafts, for the treatment of peri-implant bony defects, during implant placement."

Part - I

      

Dr . Yousef Abd ElGhaffar ,   

BDSc, MDSc,  Cairo University, Egypt

Fellow of ICOI and Member of AAID.

Email : dr_yousefabdelghaffar@hotmail.com

 Success of osseointegrated implants has been validated over the past 30 years as a viable alternative to fixed or removable prosthetic restorations. An increasing number of well-controlled longitudinal studies have demonstrated that osseointegrated oral implants are a predictable therapy for the replacement of missing teeth (Rutar et al. 2001). Tooth restoration using implant-supported prosthesis for functional and esthetic rehabilitation has become an established and widely used treatment modality in dentistry ( Von Arx et al. 2001).

  Dental implants are one of the fastest growing dental technologies of the 21st century. Millions of people scanning the globe are recipients of this fascinating development, ranging from its most primitive stages to latest inventions. Phenomenally, many of these individuals function day to day without anyone they encounter ever realizing that they are not looking at the patient’s natural dentition. In fact, these patients may even forget that they are functioning with an implant. Implants have also been a blessing to countless numbers of denture patients that became fed up with their dentures which are easily and embarrassingly dislodged. Now their implant supported dentures remain secured, putting the patient at ease (Iacono et al. 2000).

  This breakthrough in implant dentistry was initiated by the discovery that dental implants made of commercially pure titanium can be anchored in the jawbone with direct bone contact by means of osseointegration (Buser et al. 1994).

  Dental implants were defined as a biomedical device composed of an alloy placed in or within the osseous tissue with the goal of restoring masticatory function and esthetics (American Academy of Periodontology, 2000).

 Osseointegration was discovered in the 1950s by Swedish bioengineer Per-Ingvar Bränemark. He realized that after implanting titanium cylinders into the femurs of rabbits, he could not extract the titanium without destroying the surrounding bone. The discovery that bone will integrate with titanium components, not rejecting the element as does other materials, was the beginning of the study of osseointegration. Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it has direct contact. In practice, this means that in osseointegration there is an anchorage mechanism whereby non vital components can be reliably and predictably incorporated into living bone and that this anchorage can persist under all normal conditions of loading (Bränemark et al. 2001).

To achieve osseointegration, adequate bone volume must be present during surgical placement of the implant fixture to keep it stable during the initial healing phase. Clinically, many situations deviate from the ideal common such as inadequate bone circumference at the crestal aspect of the fixture or a thin shell of cortical bone that may fracture away from part of the fixture, offering little potential for integration at this site (Spiekermann 1995).

At the time of implant placement, anatomic bone deficiencies will result in exposed implant surfaces, reduced bone-to-implant con­tact, and as a consequence, compromised results varying from early implant failures to late peri-implant infections (Newman and Flemmig 1988).

Clinical studies have clearly demonstrated that the success rate of Bränemarkimplants is compromised in areas of poor bone qual­ity or in those with good quality but inadequate bone height and the long-term prognosis of dental implants is adversely affected by inadequate bone volume at implant recipient sites (Engquist et al. 1988 and Jaffin et al. 1991).

The placement of implants in sites where the bone volume is equal to or less than the size of the implant results in part of the implant surface not being covered by bone, with possible peri-implant soft tissue irritation, decreased bone-implant contact surface, and potential implant failure. A minimum buccolingual width of 5 mm is recommended for placement of implants without undesirable complica­tions (Boyne et al. 2001 and Allum et al. 2002).

Moreover, adequate bone volume at the implant site is a prerequisite for good esthetic outcome. Alveolar deficiencies can often prevent ideal implant placement. Furthermore, the gingival margin and papillae, which contribute to the esthetic outcome, are dependent on support from the underlying vital bone (Sethi and Kaus 2001).

The most common complication associated with placement of implants in narrow alveolar ridges or in an ideal position for esthetics are dehiscence and fenestration defects (Dahlin et al. 1995). An implant dehiscence is defined as exposure of the implant surface from the top of an implant head to the point where the implant is totally covered by bone (Jovanovic et al. 1992). An implant fenestration or window of exposed implant surface results from either insufficient buccolingual alveolar width or inadvertant misdirection of implant placement (Lindhe et al. 1998).

To achieve implant supported dental restorations in patients with limited bone volume, augmentation or rebuilding of the alveolar ridge must be performed. The final objective is to restore or preserve the height, width, depth (quantity), and quality of the bone for dental restoration (Brugnami et al. 1999). 

Many authors experimented augmentation of bone deficient recipient sites by various means to achieve sufficient bone volume around the dental implants, including bone grafting alone (Misch and Dietsh 1994, Lew et al. 1994, Misch 1997, Verhoeven et al. 1997, Hall et al. 1999, and Van Steenberghe et al. 2003), use of barrier membranes alone(Sevor et al. 1993, Schliephake et al. 2000, Francisco et al. 2001, and Oh et al. 2003), or combined use of both bone grafting and barrier membranes (Hockers et al. 1999, Carpio et al. 2000, Brunel et al. 2001, Rosen and Reynolds 2001, VonArx et al. 2001, Tawil et al 2001, and Zahran and Al-Shirbiny  2003). Other means for placing implants in bone deficient recipient sites was also investigated including ridge expansion (Scipioni et al. 1994), distraction osteogenesis (Oda et al. 1999), sinus elevation, tuberosity and pterygoid implants and zygoma fixtures (Balshi and Wolfinger 2003), and last but not least nerve lateralization (Garg and Morales 1998).

Bone grafts and their substitutes are evaluated from an understanding of the mechanism of bone formation processes which include osteogenesis, osteoinduction and osteoconduction.

Graft osteogenesis: The cellular elements within a donor graft, which survive transplantation and synthesize new bone at the recipient site.

Graft osteoinduction: New bone realized through the active recruitment of host mesenchymal stem cells from the surrounding tissue, which differentiate into bone-forming osteoblasts. This process is facilitated by the presence of growth factors within the graft, principally bone morphogenetic proteins (BMPs).

Graft osteoconduction: The facilitation of blood-vessel incursion and new-bone formation into a defined passive trellis structure.

All bone graft and bone-graft-substitute materials can be described through these processes (Greenwald et al. 2001).

The autograft is tissue from one person or animal that is transferred from one portion of the body to another. The allograft is tissue that is transferred from one individual to another individual of the same species. The xenograft is tissue that is taken from animals and transferred after processing to an individual of a different species (Newton and Nunamaker1985). Alloplasts or synthetic bone substitutes are synthetic commercially available bone substitutes which can also be used as a grafting material around implants (Hall et al. 1999).

At the present time it is very popular to use a plasma product by spinning down blood from the patient to obtain a platelet-derived growth factor (PDGF) which can be mixed with other osseous graft materials and placed in the defects around implants to restore alveolar bone. The platelet-derived growth factor may assist in the healing of soft tissues of the alveolar ridge, so it may eventually affect the overall osseous healing, but it is less effective in the formation of bone than BMPs. An advantage of platelet-derived growth factor is that it can be taken from the same patient and simply given back to the patient as an autogenous graft material (Becker et al. 1992 and Boyne 2001).

The autogenous bone grafts are considered to be the gold standard for bone grafts as it is the most predictable material that possess both osteoconductive and osteoinductive properties. They stimulates non-differentiated mesenchymal cells to form new bone ingrowth with no risk of disease transmission. Moreover, they do not induce an immunologic reaction (Al Ruhaimi 2001). Autografts show higher bone-to-implant contact more than other bone grafting materials with minimal or no fibrous tissue between the newly-formed bone and the implant surface in regenerated defects around implants (Hockers et al. 1999).            

Allografts such as freeze-dried bone allografts (FDBA) and demineralized freezed dried bone allograft (DFDBA) are used to treat bony defects with its success attributed to its osteoinductive potential (Hall et al. 1999). Freeze-drying of bone allograft material markedly reduces the antigenicity of the allograft. Animal studies indicate that demineralizing bone which is followed by freeze drying, significantly enhances the osteogenic potential of the allograft, supposedly by exposing the "bone morphogenetic proteins" (Blumenthal and Steinberg 1990). Bone morphogenetic proteins (BMPs) are natural proteins which are primarily morphogenetic in nature, changing the stem cells directly to osteoblasts to initiate bone formation and the regeneration cascade (Cochran et al. 2000 and Hanisch et al. 2003).

However, other studies suggested that the quantity of BMP in allografts was too small to induce bone formation. The quantity of the BMPs is also variable according to the age of the donor (Spampata et al. 1992 and Schwartz et al. 1998).

Xenografts are used for their osteoconductive potential but they lack osteoinductive potential. Xenografts have many types according to their source of origin, such as bovine (BioOss), porcine, equine, and coralline xenografts. Pep Gen-15 is a natural, anorganic, microporous, bovine-derived hydroxyapatite bone matrix which was used in combination with a cell binding polypeptide that is a synthetic clone of the 15 amino acid sequence of type І collagen. The addition of the cell binding polypeptide was shown to enhance the bone regenerative results (Yukuna et al. 2000). Xenografts are also manufactured from calcifying marine algae named coralline officinalis (Frios Algipore) (Schopper et al. 2003).

Xenografts were used extensively in Europe as the law is still uncertain about the use of allografts due to the hazards of disease transmission through donor cadavers. Nonetheless, it was reported that some dangerous diseases such as bovine spongiform encephalopathy could be theoretically transmitted to the recipient patient (Sogal and Tofe 1999).

Alloplasts include different types of alloplastic materials commercially available as nonporous dense hydroxyapatite, porous hydroxyapatite, beta tricalcium phosphate, and HTR polymer (a calcium layered polymer of polymethylmethacrylate and hydroxyethylmethacrylate) (Gross 1997).

Bioactive glasses could be used also as bone substitutes. Bioactive glass was initially introduced to dentistry as a method of filling osseous defects. This biocompatible material is composed of 45% SiO2, 24.5% CaO, 24.5% Na2O and 6% P2O5 (Cordioloi et al. 2001). However, bioactive glass alloplasts have a limited criterion of success to be used with dental implants. Histologically, alloplasts acted almost as biocompatible fillers, induced little bone fill and were encapsulated by connective tissue (Yukuna 1994).

Autogenous bone grafts can be obtained either from extraoral sites or intaroral sites. Several methods were developed to obtain autografts such as monocortical graft splitting using burs, microsawing disks  and chisels, trephining (Dennis et al. 1999), scraping, cancellous bone and bone marrow excavation, bone collectors (Kainulainen and Oikarinen 1998),  laser microsawing (Frentzen et al. 2003), and piezoelectric devices (Varcelloti 2000)...

to be continued in next issue

 

 

 

  RASHA RECOMMENDS .............

-Dr.Rasha Seragelden

 Egypt

 

Career Options in Dentistry

-Dr.Vinayak Joshi

SUNY at Stony Brook NewYork

USA

I have always believed that every specialization is good in itself, having its own share of uniqueness and a person can be the best in just any field he is in by commitment and hard work. Like any other dental graduate I had this time in my life when deciding on what I do after my graduation was a big question. This has been quite a perennial question in all the freshly graduated students. With so many specialization to choose from and with the options of general or specialized practice one is left quite confused what to do and whom to ask for guidance. Let me try to address various career options available to a dental graduate.

1) Academics: One can choose to be in academics being a full time academician. This is possible after any specialization (i.e. periodontics, prosthodontics, etc..), one can be a full time faculty in the department of his /her field of specialization. An additional PhD would be helpful for a full time faculty.

2) Basic research: A good training in basic research is necessary and can be attained with a good masters or PhD program. Additional training can also be obtained by working as post doc in specific areas of interest. Areas such as biomaterials, immunology, microbiology are few areas one can look into but generally the field of research vastly depends on ones own interest. Basic research mainly deals with research carried out in the lab setup or studies on animal models or epidemiological studies. Basic research is always in demand and is the cornerstone for all the new techniques and new materials been developed.

3) Clinical research: A specialization in any particular field with additional training in research is necessary. This field basically deals with clinical testing of the materials discovered/invented in the lab (basic research). Translation of the results obtained in the lab setting into a clinical setup, for example, testing various bone graft materials already tested in animals on to human subjects ,looking for efficacy of drugs, or testing different tooth implant systems in a clinical setting. This is a very interesting field especially to those who are good clinicians and are inclined towards research. Specialized program for training in clinical research are also available.

4) General or specialized private practice: This is possible with either a DDS/BDS alone or with additional specialized training in various fields respectively. Various centers and institute provide specialized training in implants, cosmetic and esthetics dentistry, endodontics and others which span from few days to few weeks or a year. Such training helps those candidates who are not much interested in a masters program but want additional knowledge to start their own specialized dental office.

5) Combination of the above: Few individuals who are good at multitasking do try this by being a part time academician and part time into private practice. Also the other combination which usually works out is being a academician and researcher. These combinations can often be rewarding as they help being adjunctive to each other and also keep out boredom of a single routine job.

6) Private Sector: Those who are not into the usual dental jobs and have a eye for change can sign up for business school. Now what am I talking about? Well a master in business administration will help you to join the private sector as a consultant for various industries dealing with dental materials/ dental consumer products. A master in hospital management/ public health may help you to work at administrative position in various hospitals. Those interested in research in private sector can think of working in industries with clinical testing various dental materials and dental consumer products with a PhD or good research experience at hand. Many companies hire people as clinical research coordinators who overlook the clinical trials, or as product development associates to help plan new product design and to conduct testings and trials.

7) Organisations and Goverments: Masters in public health would help those interested in epidemiologic studies or taking up jobs which include making strategies to combat disease and helping governments and non government agencies plan and induct preventive programs. They also have options of joining agencies like WHO or various UN agencies.

The various options to the dentist in so many different countries are limited and these graduates look to continue their future studies in countries like USA and UK. I have received so many emails asking for the procedure to get into US dental schools. Let me try to briefly sum up few steps in how to go about it.
The first thing to be understood is that you need to get license to practice in US, most of which can be learned by visiting the ADA website (http://www.ada.org/prof/prac/licensure/us.asp). All international dental graduates (other than from US and Canadian dental schools), are required to complete an additional 2-3 years of DDS training in a US dental school. The list of the dental schools can be found on the ADA website (http://www.ada.org/prof/ed/programs/search_ddsdmd_us.asp) and the requirements of each university mentioned on the respective websites. Ideally you would need your TOEFL scores, 2-3 letters of recommendations and statement of purpose and national board examination scores (http://www.ada.org/prof/ed/testing/natboard/index.asp). The other important thing to be noted is that the fees for the dental schools vary between 60,000 – 85,000$ per year and financial aid to foreign dentist in form of scholarships/stipend is mostly not available and other financial aids are very limited, the exact details of this can be found on the university website. More information can be also found on http://www.studentdoctor.net/
Many students initially join the masters in public health/oral biology, this also helps them adjust to US and to prepare for the national board exams. Kaplan used to provide I-20 to students who enroll for their national board examination training, which students can use to apply for the F-1 visa. This has been very recently stopped, you can find more of it on this groups (http://groups.msn.com/dentalsurgery/general.msnw). A good score in NBDE exams is essential as there is a very stiff competition for the limited seats of the Advanced DDS program for the international graduates.


Those wishing to go in for PhD need to submit your GRE scores, TOEFL scores, recommendation letters and statement of purpose. Mostly the PhD students are paid a monthly stipend and have the tuition fees covered by the university/department. You need to decide which university you want to apply by looking in to each university website and finding out if research in area of your interest is been carried out in that university. Also important is to find out if that particular professor with whom you want to work has an approved grant and is willing to sponsor you, and this can be found by looking up the university website and/or by directly contacting the professor. These are few of the pre requisites of an application. Most universities offering doctoral studies can be found on http://www.perio.org/education/us.html

Wishing every aspirant the very best!

EVENTS

India International Dental Congress -Mumbai ,India Feb 23rd to 25 2007

 

Could what we see in our CLINICS be EVIDENCE?!

Maziar Mir

DDS, MSc, PhD

Assistant Prof. ZPP, RWTH Hospital, Aachen, Germany

 

Most of the Dental Clinicians, when hear about a new equipment, just buy it and try it! If works well will take the advantage of treatments assisted by that, but if does not work well?! Who is responsible for the troubles and side effects? 

When first Endo Rotary files were introduced to the market, one Endodontist friend of me bought a Japanese one and at the first week all files of the kit were gifted to the patient's teeth canals, because of mishandling of machine! I mean they were all broken inside the canals and he left them there! 

My professor, from the first day told me very serious that please take photograph from all the phases of procedures that you will do with laser. I started with normal digital cameras and for any patient made a FOLDER in my computer. After three years, we had a collection that could show us the success rate of a variety of methods we applied in practice. I was very happy that felt proud of having such a back bone for what I daily do. Parallel to these Folders, some thing about 500 articles were also automatically colleted in my computer, from different aspects of Laser Applications in Dentistry! I was looking for a way to bring my knowledge and CLINICAL experiences together and could build up a CROWN out of them to be the BASE of my professional work kingdom. 

About November 2005, again the Professor asked me for a short talk and informed me about an Event?! He told me that 16 of the Pioneers of Lasers in Dentistry are invited to come to our university for making a professional congress" Evidence Based Laser Dentistry”. 

That was really surprising for me and it was my duty to collect all of the papers and classify them in different orders to make them able to have fast access to any literature they wish during the congress. 

It was a three HARD days’ work, from 8 AM till 5 PM, just one hour lunch break for eating some thing LIGHT. I was mostly helping all of the professors to find the right articles form our DATA BANK. Also, it was a part of my duty to help to Prof. Dr. Ishikawa (Tokyo, JAPAN) and some other professors in writing the conclusion out of all the papers in any field.  

I learned more that what was estimated and could feel that know nothing and need to do active research for a long time to have some EVIDENCE only in an small part of Dentistry while applying lasers! 

What the professors read, discussed and wrote gave me new concepts and they are yet after one year discussing to complete the work and I wish that the collection be published till end of year by QUINTESSENCE. The book is called “Proceeding of First congress of Lasers in Dentistry”.  

Dr.Maziar Mir working on a patient

 But back to the CLINIC, we are not anymore bothering the patients for taking photographs and now use a microscope and record all the procedures we do on DVD. These clinical treatments now are based on the GOVERNMENT of EVIDENCE. We are looking forward to collect more and more INFORMATION and produce more and more knowledge and gift them to all dentists all around the world.