Maxillary Ridge Research Articles

Effect of attachment height on chewing efficiency for mandibular over denture wearer

Purpose: The intent of this research was to study the effect of attachment height on chewing efficiency of the patients wearing mandibular overdenture Materials and methods: Twelve male patients had completely edentulous maxillary and mandibular ridges, were elected to perform this study. All Patients received complete maxillary denture and mandibular over denture retained by two implants with locator abutments divided into two equal groups according to the length of the locator attachment.GroupI: the patients were received locator abutment with 1mm in height.Group II: the patients were received locator abutment with 3mm in heightColored chewing gum used for estimation of chewing efficiency of the patients by the help of special software programs. The data was reordered and statistically analyzed at( two, four &six) weeks from over denture insertion .Results: between groups the results of this study reveled that Group II representing higher means of Delta E values than group I throughout different follow-up periods. These values were statistically significant at four and six weeks from over denture insertion at p ≤ 0.05 .Within groups the results of this study presented that the means of Delta E values for group I& group II increase throughout different follow-up periods. These values were statistically non significant at all observation periods for group I and statistically significant for group II at p ≤ 0.05. Conclusion: Within the restrictions of this study it could be concluded that, the attachment height affects chewing efficiency of the patient.

Analysis of the Stress Distribution Pattern of Anatomic and Non-Anatomic Tooth Forms on Maxillary and Mandibular Edentulous Ridges—A Photoelastic Study

Aim: To compare the type of stress distribution pattern occurring with anatomic and non-anatomic tooth forms beneath a complete denture in both maxillary and mandibular arch. Methodology: A photoelastic model of the edentulous maxillary and mandibular ridge was prepared meticulously to simulate the human mandible and maxilla. Two sets of acrylic teeth with anatomic and non-anatomic occlusal forms were used to fabricate upper and lower dentures. A vertical static load of 100 N was applied through the mandibular model to the maxillary model. After load application on the dentures the photoelastic model as well as the upper and lower complete dentures were sectioned in the midline. The sectioned photoelastic model was viewed through a polariscope to observe the fringe pattern indicating varying amounts of stress distribution. In this study, a two-dimensional photoelastic stress analysis technique was utilized. Results: Force per unit area was observed more in anatomic teeth than the non-anatomic counterpart. Hence anatomic tooth forms may increase the possibility of bone resorption rate over a period of time. However, in non-anatomic lower teeth, a decrease in value was observed from posterior to anterior region. Conclusion: Stress of greater magnitude was observed with cuspal teeth whereas non-anatomic (0°) showed slightly less magnitude of stress. Depending upon the clinical situation the clinician needs to choose the type of occlusal tooth forms for edentulous patients.

Prosthodontic management of maxillary flabby ridge and the resorbed mandibular ridge

The management of resorbed mandibular ridge and the flabby ridge has always been a challenge for prosthodontist. Many patients cannot be suitable for implant denture therapy. Hence, in such patients to use a technique with routinely used impression materials becomes a justified option. Hence, the stability of denture in such patients becomes a distinguishable factor between failure and success. This article outlines a combination of different impression materials to improve denture stability in atrophied mandibular ridge, and management of flabby tissue keeping in mind further ridge resorption.

The concept of neutral zone and rehabilitation of severely resorbed alveolar ridges: A special case file

Mandibular dentures often present greater difficulty in achieving retention, stability, and support than do maxillary dentures, primarily, due to a complex anatomy because of bone architecture and muscle attachments, and consequently, increased number of anatomic limitations. Long-term edentulism as well as prolonged use of ill-fitting dentures result in severe resorption of the alveolar ridges, further, worsening this situation. The present case report describes a similar case of a 90-year-old male patient who reported to the department of prosthodontics seeking replacement of his missing teeth. On examination, the lower denture was ill fitting with a severely resorbed mandibular alveolar ridge. Intraoral examination revealed an Atwood's Class III maxillary edentulous ridge with Class VI edentulous mandibular ridge. Special measures were adopted for the management of the patient through a modified impression technique along with physiologic registration of the neutral zone.

”Myxoma of the Jaws”: Report of an atypical presentation and review of literature

Oral lesions of myxomatous origin are relatively rare and include nerve sheath myxomas, soft tissue myxomas, oral focal mucinosis, and odontogenic myxomas. These lesions have a common histologic appearance of abundant myxoid ground substance. A 61-year-old edentulous female presented with nasal stuffiness since the past 4 months. Clinical examination revealed an asymptomatic intraoral swelling in the edentulous maxillary ridge which had ulcerated. Plain film radiography and CT showed an expansile osteolytic lesion involving the right maxillary sinus. A partial maxillectomy was performed and direct microscopy showed a predominant embryonic mesenchymal stroma with fibroblasts and calcifications suggestive of a myxoma. The central myxoma is hypothesized to originate from the odontogenic apparatus due to its almost exclusivity to the jaw bones. However, when a central myxoma occurs in an edentulous jaw at an age when the odontogenic apparatus is apparently nonfunctional, explaining the genesis of this unique tumor based on present understanding becomes difficult. We present one such case while reviewing the existing literature on the present concepts of pathogenesis.

Modified Impression Technique to Overcome Flabby Anterior Maxillary Ridge and Severe Residual Mandibular Ridge Resorption - A Case Report

Modified Impression Technique to Overcome Flabby Anterior Maxillary Ridge and Severe Residual Mandibular Ridge Resorption - A Case Report

Classification of Sinus Membrane Perforations Occurring During Transcrestal Sinus Floor Elevation and Related Treatment.

The predictability of transcrestal sinus floor elevation (tSFE) in elevating the sinus membrane following posterior maxillary ridge resorption has been widely demonstrated. To minimize complications and increase success, a literature search was conducted to validate procedures used for tSFE. A decision tree based upon timing of perforations was then developed to improve membrane-perforation management during the procedure. At each surgical procedure, the clinician is encouraged to use size of the perforation, time during the procedure in which the perforation occurred, and resulting symptoms to determine the best treatment approach. This article discusses all possible sinus membrane perforations based on timing of that surgical procedure, allowing the clinician to recognize and successfully rectify this clinical complication while successfully completing the surgery. With this aim, a classification of sinus membrane perforations occurring during tSFE is proposed, simultaneously providing guidelines to effectively manage these complications.

Role of zygomatic implants in functional rehabilitation of severe atrophic maxillary ridge

Role of zygomatic implants in functional rehabilitation of severe atrophic maxillary ridge

All on 4 Versus All on 6 implant concepts for rehabilitation of edentulous maxilla. Short term randomized clinical and radiographic study

Purpose: The aim of the present study was to evaluate clinical and radiological outcomes of “All on 4” Versus “All on 6” implant concepts for rehabilitation of edentulous maxilla. Materials and methods: 10 patients with complete maxillary edentulism and distal extension mandibular ridges who had resorption in the posterior aspects of the maxillary ridge were randomly assigned into 2 groups: Group 1 included 5 patients who received All on four maxillary prosthesis, and group 2 included 5 patients who received All on six maxillary prosthesis. Four (group 1) or six (group 2) implants were inserted between the maxillary sinuses and immediately loaded by provisional acrylic dentures. Definite screw retained porcelain fused to metal fixed prosthesis were inserted after 6 months. Plaque index, gingival index, probing depth, implant stability, and peri-implant bone loss were measured for both groups at base line (after insertion), 6 months and 12 months after insertion. Results: The survival rate was 85% and 100% for group 1 and group 2 respectively. Plaque and gingival scores significantly increased with time in group 1 only. At 6 and 12 months, group 1 showed significant higher plaque and gingival scores than group 2. Pocket depth and implant stability increased significantly with time in both groups. Group 1 showed significant higher pocket depth and reduced implant stability than group 2 at all observations. Bone resorption significantly increased after 12 months compared to 6 months in both groups. Group 1 recorded significant higher bone loss than group 2 after 6 and 12 months of prosthesis delivery. Conclusion: Within the limitations of this study, it could be concluded that All on 6 implant concept is recommended for restoration of atrophied maxilla compared to All on 4 implant concept as it was associated with improved clinical and radiographic parameters after one year.

Clinical Evaluation of Residual Ridge Morphology of Maxillary Arch in Relation to Ageing and Length of Edentulism

Background: Ridge morphology is one of the important recognized factors affecting denture retention, stability, support and masticatory function in edentulous patients. The form of ridge affects the planning as well as determines the prognosis of treatment. The objective of this study was to assess maxillary residual ridge morphology according to American College of Prosthodontists (ACP) classification system and to find association between type of ridge morphology of maxillary arch with age and duration of edentulism. Methods: The study was conducted among 87 completely edentulous patients above 40 years of age visiting department of prosthodontics Nepal Medical College. The morphology of maxillary residual ridges were clinically evaluated and classified according to criteria given by American College of Prosthodontists (ACP) classification system. The findings were associated with age, sex, duration of edentulism and complete denture wear. Results: In this study, more than two thirds of the patients belonged to the age group of 60 – 80 years and their mean duration of edentulousness was seen to be 5.7 years. One fifth of the patients were using previous complete dentures. Type A maxillary ridge morphology was found to be the most prevalent. The type of maxillary ridge morphology was not found to be associated with either age or gender of an individual however it varied significantly with length of edentulism and duration of complete denture wears. Conclusions: Within limitations, it can be concluded that maxillary ridge morphology was not associated with age of an individual however the longer duration of edentulism or complete denture use would make the type of ridge morphology more unfavorable.
 Keywords: maxillary ridge; length of edentulism; residual ridge resorption; ridge morphology.

Combined use of xenogenous bone blocks and guided bone regeneration for three-dimensional augmentation of anterior maxillary ridge: A case series.

Background Bone augmentation ensures a favorable 3-dimensional position of implants. Onlay grafting is one of the techniques in ridge augmentation, which can be performed with the use of xenogenous blocks. Methods Three cases of the vertical and horizontal ridge are discussed, which were augmented using xenogenous blocks. The blocks were shaped in a favorable size and puzzled along the grafting area. All the gaps were filled with granular xenografts. The flaps were coronally advanced to obtain primary closure. Results An average of 4.2-mm gain in width and 4.2-mm gain in height of the ridge was observed at the implantation stage. Conclusion The outcomes of these cases could pave the way for suggesting xenograft blocks for augmenting wide areas of the alveolar ridge on average of 4 mm in width and height in selected cases as an alternative to standard autogenous blocks. Long-lasting xenograft ensures implant and lip support in the esthetic zone.

HISTOPATHOLOGIC ASPECTS OF JUVENILE OSSIFYING FIBROMA

Juvenile ossifying fibromas (JOFs) are benign fibro-osseous neoplasms observed in young individuals that, in cases of gneissic bones, are preferentially located in the maxilla and have histopathologic features very similar to other benign fibro-osseous lesions (BFOL). A 17-year-old male adolescent presented asymptomatic volume increase located in the right maxillary ridge region with a 6-month history of radiographic examination, showing the presence of mixed lesion with clear borders and a radiopaque center, an aspect of ground glass, and displacement of teeth. Histologic sections stained with hematoxylin and eosin (HE) revealed fragments a JOF with presence of cellular fibrous connective tissue containing spherical ossicles with basophilic centers and peripheral eosinophilic margins with JOF diagnosis. In this case, the outstanding histopathologic characteristics of the JOF are presented to differentiate it from the BFOL.

Fresh-frozen homologous bone in sinus lifting: histological and radiological analysis.

The aim of this study was to evaluate radiological and histological characteristics of fresh-frozen homologous bone as grafting material for maxillary sinus floor augmentation. Radiological, histological and clinical evaluations were made. Twenty-three patients with a 2 mm to 6 mm alveolar ridge height in the posterior maxilla have been enrolled. Unilateral or bilateral sinus floor augmentations were performed with fresh frozen morcelized homologous bone. Together with implant placement, 7 months after surgery, a bone core was harvested for histological analysis. Radiological measurements were obtained by superimposition of CT scans carried out at the surgery time and six months later. A total of 93 implants were positioned. A mean (±SD) increase in mineralized tissue height of 10.74±2.82 mm was noticed by comparing the CT scans. Histological analysis revealed the presence of newly formed bone in the grafted sites. The follow up period after the prosthetic load ranged from 8 to 31 months. One implant failure occurred. Fresh frozen homologous bone seems to have a good healing pattern and to be a successful and steady grafting material for the treatment of maxillary ridge atrophy. It might be considered a valid alternative to autologous bone in sinus floor augmentation procedures.

Bone augmentation in atrophic maxillary ridge by ridge split technique and guided bone regeneration: A case report

Bone loss after tooth extraction is inevitable, it can be horizontal, vertical bone loss or combination. Now a days, dental implants are emerging as a better treatment option for oral rehabilitation and become an integral part of dentistry ,thus availability of adequate bone volume in all 3-dimensions to stabilize implant is foremost requirement for successful treatment. Various methods have been used to augment the ridge bone volume which includes bone grafting along with guided bone regeneration, ridge split technique, sinus lift procedure and distraction osteogenesis. This case report presents aesthetic rehabilitation by implant retained prosthesis in upper anterior region with large defect by combining bone augmentation with ridge split technique to enable implant placement. Keywords: Dental implants, Ridge split technique, Bone augmentation, Bone grafting, and Implant retained prosthesis.

Clinical and radiographic outcomes of polyetheretherketone (PEEK) hybrid prosthesis used for “All on four” rehabilitation of edentulous maxilla. A short-term case series study

Purpose: The aim of this study was to evaluate clinical and radiographic outcomes of polyetheretherketone (PEEK) hybrid prosthesis used for “All on four” rehabilitation of edentulous maxilla.Materials and methods: Six patients with atrophied edentulous maxillary ridges were managed by 4 implants according to the “All on four” protocol using computer guided surgery and flapless surgical approach. The existing maxillary dentures were placed immediately after modifications on the same day. After 6 months, the definite prosthesis consisted of screw retained milled BioHPP framework bonded to acrylic resin teeth and denture base. The prosthesis restored lost teeth, hard and soft tissues (hybrid fixed prosthesis). Plaque and gingival index, probing depth, implant mobility and bone loss (measured by standardized periapical radiographs) were evaluated after prosthesis delivery (T0), six months (T6) and 12 months (T12) after delivery.Results: Two implants failed in one patient resulting in 91.7% survival rate. Plaque index increased with time. No difference in gingival index, pocket depth, implant stability, and vertical bone loss between observation times was noted. Posterior implant showed higher plaque scores and pocket depth than anterior implants after 6 and 12 months and no significant difference in all other parameters between anterior and posterior implants was noted. Conclusion: Within the limitation of this study, PEEK hybrid prosthesis bonded to acrylic resin teeth and denture base can be used successfully to rehabilitate patients with atrophic maxilla according to “All on four” concept as it was associated with favourable clinical and radiographic outcomes after one year.

Horizontal Ridge Reconstruction of Atrophic Anterior Maxillary Ridges Using Customized Xenograft Bone Shell With 1 :1 Mixture of Autogenous and Xenograft Bone Particulate

Horizontal Ridge Reconstruction of Atrophic Anterior Maxillary Ridges Using Customized Xenograft Bone Shell With 1 :1 Mixture of Autogenous and Xenograft Bone Particulate

Clinical and radiographic outcomes of allogeneic block grafts for maxillary lateral ridge augmentation: A randomized clinical trial

A main drawback of bone block graft surgery is the resorption occurring in early stages of healing. To our knowledge, there are no studies comparing outcomes of freeze-dried bone allograft (FDBA) blocks with different architecture. The aim of this work was to investigate different factors that can affect graft resorption and to compare the resorption rates of two different types of allogeneic blocks, corticocancellous and cancellous. A randomized clinical trial was designed. Twenty-eight patients referred for onlay bone augmentation prior to implant placement were included in the study. Preoperative computerized tomography (CT) was taken for all patients. Patients received FDBA blocks of either cancellous or corticocancellous bone obtained from the iliac crest. After a 4-month follow-up, postoperative CT was taken. Then, another surgery was performed, with the purpose to place dental implants. The aforementioned groups were compared for bone resorption and implant outcome using analysis of covariance (ANCOVA) and repeated ANOVA measures, respectively. Demographic data, trabecular bone density, and graft sites were also analyzed. A total of 93 implants were placed in the augmented bone sites over 28 patients. A 100% survival rate was achieved during a mean follow-up period of 24 months in both groups. Higher bone resorption rate was found with cancellous bone grafts (29.2% ± 2.6) compared with corticocancellous grafts (19.3% ± 2.3). Moreover, higher resorption rates in patients with lower bone density (<185 Hounsfield Units) (31.7% ± 3.1) and smokers (26.39% ± 2.3) were observed when compared with patients with higher bone density (>185 Hounsfield Units) (16.8% ± 2.1) and nonsmokers (22.1% ± 2.3), respectively. Within the limitations of this study, these findings indicate that both corticocancellous and cancellous FDBA grafts constitute a clinical acceptable alternative for bone reconstruction, although cancellous grafts present higher resorption rates. Moreover, host factors such as patient's low bone density and smoking habits may also increase graft resorption rates.

Human Bone Marrow-Derived Mesenchymal Stromal Cell-Seeded Bone Biomaterial Directs Fast and Superior Mandibular Bone Augmentation in Rats

Atrophic maxillary ridges present a challenge in the field of oral implantology. Autologous bone is still considered the gold standard grafting material, but the increased morbidity and surgical complications represent a major drawback for its use. The aim of this study was to assess the efficacy of an off-the-shelf cell-seeded bone biomaterial for mandibular bone augmentation, compared to its acellular counterpart. We used a rat model to test the osteogenic properties of bone marrow-derived mesenchymal stromal cells (MSCs)-seeded bone microparticles compared to acellular bone microparticles alone. Rats were euthanized at 4 and 8 weeks, and results analyzed using micro-CT imaging, histology (H&E, Masson’s Trichrome), histomorphometry and immunohistology (Tartrate-Resistant Acid Phosphatase-TRAP, Osteocalcin and human specific anti-mitochondria antibodies). Micro-CT analysis demonstrated that the cell-seeded biomaterial achieved significantly more bone volume formation at 4 weeks (22.75 ± 2.25 mm3 vs 12.34 ± 2.91 mm3, p = 0.016) and at 8 weeks (64.95 ± 5.41 mm3 vs 42.73 ± 10.58 mm3, p = 0.029), compared to the acellular bone microparticles. Histology confirmed that the cell-seeded biomaterial was almost completely substituted at 8 weeks, in opposition to the acellular biomaterial group. Immunohistochemical analysis showed a significantly higher number of TRAP and Osteocalcin positive cells at 4 weeks in the cell-seeded group compared to the acellular group, thereby demonstrating a higher rate of bone remodeling in the presence of MSCs. The grafted human cells remained viable and were detected up to at least 8 weeks, as observed using the human specific anti-mitochondria antibody. This off-the-shelf material available in unlimited quantities could therefore represent a significant advance in the field of mandibular bone augmentation by providing a larger volume of new bone formation in a shorter time.

The Comparison of Utilizing Piezotome and Surgical Disc in Ridge Splitting of Atrophic Edentulous Maxillary Ridge

Narrow dentoalveolar ridges remain a serious challenge for the successful placement of dental implants. The aim of this study was to compare the clinical outcomes of piezosurgery versus surgical disc on ridge splitting in the atrophic edentulous maxilla. This was a double-blinded randomized clinical trial. The healthy subjects who were candidates for maxillary ridge expansion were included in this experiment. Patients were randomly divided into two groups: piezosurgery group and surgical disc group. The width of the bone in the surgical site was measured by surgical calliper before the osteotomy. The bone width was remeasured after ridge-split completion (before suturing) and during the implant placement (4months later). Then data were analysed by SPSS software, and the P value was set at 0.05. The study sample size included 20 cases. Our outcomes showed that both techniques (surgical disc and piezotome) were effective in ridge splitting (P < 0.001). However, the average bone width which was obtained after ridge splitting was significantly higher in the piezosurgery group (P < 0.05). It can be concluded that both methods of piezosurgery and surgical disc can significantly lead to increase in the ridge width. However, the piezosurgery technique was more effective in ridge splitting.

A Two-step Method for the Preparation of Implant Recipient Site in Severe Atrophic Maxilla: A Case Report of the Alveolar Ridge Split Technique Followed by Bone Expansion

Augmentation of deficient and atrophic alveolar ridges is an important aspect of dental implant therapy with the goal of providing a functional restoration in harmony with adjacent natural dentition. Bone splitting technique is considered a distinguished augmentation method for treatment of deficient alveolar ridges. According to this procedure, the compromised alveolar ridge is opened from the crest of the ridge and subsequently split with special chisel instruments. In this report, we described a case of horizontal ridge augmentation of an atrophic anterior maxillary ridge using ridge split in the first step and ridge expansion concomitant with implant placement in the second stage after 6 months. A two-step method of alveolar ridge split using piezosurgery followed by bone expansion is a reliable and successful treatment plan for implant recipient site rehabilitation in severe atrophic maxilla (less than 3 mm).