Types of Grafts in Dentistry

TYPES OF GRAFTS:

Osseointegrated implants can be combined with the following

types of graft: inlay, saddle, veneer, onlay (partial or full arch), and maxillary sinus grafts. (Triplett & Schow, 1996)

The mucoperiosteal flap should be designed to adequately expose the underlying residual ridge, maintain a broad base for vascular support, and allow tension-free primary closure. A midcrestal incision is usually preferred because it maximizes the vascularity to the margins of the mucoperiosteal flaps and minimizes ischemia created by the vasculature traversing dense, keratinized tissue at the crest of the ridge. Labial vertical releasing incisions are made as needed to improve access. All grafts must be well adapted to the recipient site with no or minimal space betveenbetween graft and residual bone. Hence, usually graft shaping and adaptation is unavoidable. The gGraft is positioned to its best adaptation to the underlying alveolus. A good fixation with titanium screws must be achieved to prevent the graft movement. Any movement of the graft increases the chance of soft tissues ingrowth between the graft and the recipient site, and thus the failure of the graft is likely. All voids or defects should be filled with particulate cancellous bone and marrow to provide good contour and eliminate dead space. A primary, tension-free closure must be achieved to prevent wound breakdown and graft exposure. A barrier membrane and filler graft may be used, if desired.

Inlay Grafts

Small osseous defects at the alveolar crest can be inlaid with an autologous graft to restore the contour and volume of bone necessary to place an the implant and allow for a proper emergence profile.

The defect is usually exposed through a crestal incision that is extended around the necks of one or two adjacent teeth on either side of the defect. A vertical releasing incision is made if necessary. A barrier membrane may be used to protect these areas during healing.

Saddle Graft

Indicated where both horizontal and vertical ridge augmentation[S1], this type of graft is also of considerable value. Aautogenous bone stabilized with rigid fixation to restore anatomic height and width is an excellent solution to this problem. A saddle of bone is obtained from the anterior-inferior border of the mandible (ipsilateral site) and secured in position from the buccal or crestal aspect with 1.5–mm titanium screws with a minimum of 2 screws to achieve stable graft fixation.

Veneer Graft

A veneer graft is preferred where there is only a horizontal bone defect of less than 4 mm. T

Onlay Graft

The design of onlay grafts can be segmental or arch in shape.

Both the height and width of an atrophic ridge can be achieved with onlay grafts. Following Iindications include the following[S2]: inadequate residual alveolar ridge height and width to support a functional prosthesis, contour defects that compromise implant support, function, or aesthetics, and segmental alveolar bone loss.

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Procedures aimed at increasing the volume of attached mucosa (free soft tissue grafts, pedicle soft

tissue grafts, and surgical extension of the vestibulum) have been recommended in areas of movable

mucosa. 75,77,102–111 [S3](Esposito, Hirsch, Lekholm, & Thomsen, 1999)

There wasIt has also been also stated that cancellous grafts are more successful because of cortical plate (“Buchman 1999 Cancelous Bone stucture.pdf,” n.d.)

Results:

1. A pPositive correlation outcome was found between age and missing teeth found in both groups A and B in the applied multiple regression analysis (SPSS)

Group A analysis for correlation between the patients age and number of teeth missing outcome:

Group B outcome:

2. A pPositive correlation was found between age and bone volume harvested in Group A. However, the correlation in Group B was non– significant.

Group A multiple regression analysis output:

Group B SPSS multiple regression analysis output:

3. The distribution for harvested overall bone volumes was found to be normal in both groups A and B and a significant correlation was found between clinitianclinician A and clinitianclinician B and their harvested bone volumes.

Distribution analysis output. Histogram:

Multiple regression analysis output for ClinitianClinician A

4. Association between a patient’s gender and performed clinicians A ands B found to be not statistically significant applying SPSS multiple regression analysis.

The SPSS output for multiple regression analysis:

5. The Aassociation between a patient’s age and clinitiansclinicians A and B was also not statistically significant (“Reszults,” n.d.). P value was more than 0.05. So the hypothesis that there is no difference between patientspatient’s age and performed clinitianclinician A and B harvested bone volumes –can not be rejected the hypothesis.

6. Nominal variables (number of teeth) were not equally distributed. So, a nonparametric Kruskal-Wallis Test was applied to test the hypothesishypostasis that there wasis no difference between the number of teeth missing and harvested bone volumes in group A and B. The hypothesis washypostasis rejected in Group A because the P value was less than 0.05. However, there was no difference in a Ggroup B (p value more than 0.05)

Number of teeth and harvested bone volumes distribution for Group A

Kruskal-Wallis hypothesis testing output:

SPSS output for Kruskal-Wallis Test Group B:

7. A bone volume’s distribution was tested by drawing a histogram to determent determine a parametric or non parametric test was needed to applyin order to test the hypothesis[S4]. The data was not equally distributed in both groups A and B. Hence, the non parametric Mann-Whitney test was applied to test the null hypothesis of if whether there is was no any difference in harvested bone volumes and the performance of theed clinicians. The P value was less than 0.05, so the null hypothesis was rejected and there is was a significant difference between cclinician A’s and clinician’s B performances.

ClinitianClinician A and B harvested bone volumes distributions:

SPSS output Mann-Whitney Test

Conclusions:

A mandibular ramus donor site can provide sufficient autologous bone volume to restore dentoalveolar defects prior to dental implantation.

PThe positive correlations were found between a patient’s age and missing teeth, between clinicians A and B and their harvested bone volumes, and between harvested bone volume and a patient’s age in a group A but this was not significant in Group B., Bbetween a patient’s age and gender in both groups A and B there was no significant correlation based on the multiple regression analysis outcome SPSS.

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To conclude, with thean increasinge in age there were a higher number of teeth missing in both groups A and B. Although, the diameter of bone reconstruction were was greater because of a more missing teeth, the harvested volumes were greater only in the Group A harvested by cClinician A (p<0.05). Moreover, there is was a significant difference between clinicians A and B and their harvested bone graft volumes in Group A and B (p<0.05). Overall, the harvested bone volume from ascending mandibular ramus depends on the person who operatesor.

In aAdditionally to mandibular, ascending ramus bone can be harvested at intraoral sites and can be considered incrementally to the performed procedure, [S5]such as the contralateral ramus site, chin, and maxillary tuberosity, where when greater bone volumes are required. Moreover, the bone materials can be also added too, increase the further if the bone volume is yet not yet sufficient. And finally, based on the literature review findings, the majority of iliac crest bone graft can be successfully replaced with ascending ramus bone grafts as the studies revealed that the harvested bone grafts are not significantly greater.

The outcome of implant therapy has been summarized in several recent reviews (Cochran 1996, Esposito et al. 1998, Fritz 1996, Fiorellini et al. 1998, Gotfredsen 1999, Mericske-Stern 1999, Van Steenberge et al. 1999) and evaluations are often reported in success and survival rates. The interpretation of the results, however, relies on the concept that different investigators use similar criteria for implant success and survival. Variations in study design and study period, and an improper definition of the selection of patients are factors that may further affect the interpretation of the data.

First, autologous bone grafts of various types to different locations can be successfully used to improve the ability to place endosseous implants. Complications that lead to failure can be minimized with experience and adherence to the basic surgical principles of rigid fixation and tension-free primary closure of the soft tissue flaps. Second, most of the grafting failures are associated with infection or exposure of the graft to the oral cavity because of mucosal flap dehiscence. Early loading of grafts with a transitional prosthesis is also a potential cause of graft compromise or failure. Third, the successful placement of endosseous implants in autologous grafts is more predictable when they are placed secondarily after bone graft consolidation; and. fFourth, whether placed immediately with the bone graft, or secondarily, failure of individual implants does not imply failure of the bone graft.

Frenuloplasty, Frenectomy, Vestibuloplasty Technique (Liposky, 1983) oOr Mandibular Anterior Ridge Extension: Modification of the Kazanjian (Al-Mahdy Al-Belasy, 1997), Vestibule and floor-of-mouth extension procedures, Soft-tissue grafts (full thickness or connective)

Although COHRANE stated that autologous is not in favour, this statement needs to be taken considered very carefulycarefully because the outcome does not measure all aspects in convensionalconventional terms of success. As stated before, a simple implants survival is no longer a single preferable outcome today. Cohrane agrees that there is littleare few randomized controlled trials and for most that are conducted today are at a high risk of bias remains.

Further more, bone augmentation, such as synteticsynthetic bone materials, provide a poorer outcome rather thaen animal retrieved bone materials. However, because of culture cultural or religious reasons animal products may not be accepted for a certain groups of patient and therefore autologous bone grafts are then isremain a single oaption to augment the alveolar crest defects.

AeEsthetics and harmony in dental implant placement was well described by Belser et al., 1998. Buccal bone thickness has toshould be a minimum of 2mm and ideally 3mm from the implant buccal surface.

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[S1]Not sure about this. Does it relate to the heading i.e. ‘Saddle graft is Indicated where both horizontal and vertical ridge augmentation…’

[S2]Please check I haven’t changed the meaning

[S3]Are these page numbers? Should it be (Esposito, Hirsch, Lekholm, & Thomsen, 1999 75,77, 102–111)

[S4]Please check 

[S5]Please check this one. I’ve read it many times and am a little confused 