Effectiveness of three treatment modalities for the edentulous mandible. A five-year randomized clinical trial

Currently, 3 treatment options are available for patients with denture complaints and an edentulous mandible with a height of at least 15 mm: meticulous construction of a new set of dentures (CD), construction of a new set of dentures following preprosthetic surgery to enlarge the denture-bearing area (PPS), and construction of an implant-retained mandibular overdenture (IRO). The aim of this study was to evaluate patient satisfaction and subjective chewing ability of edentulous patients treated with one of these treatment modalities. Ninety edentulous patients (Cawood class IV and V, mean mandibular height 20.7 mm) were randomly assigned to receive 1 of these 3 groups. Denture satisfaction and chewing ability were assessed using questionnaires focusing on denture-related complaints and problems chewing different types of food were assessed before treatment, and 1- and 5-years after treatment. At the 1-year evaluation, significantly better scores were observed in the 2 surgical groups (IRO, PPS) than in the CD group. At 5-year evaluation the "complaints of the lower denture" showed a significantly better score in the IRO group when compared to the PPS and CD groups. No significant differences were observed between the PPS and CD group. From this study it is concluded that both in the short and long term denture satisfaction appears most favourable in the IRO group when compared to the PPS and CD groups. Implant-retained overdentures are therefore a satisfactory treatment modality for edentulous patients with problems with their lower denture, even in cases of not severely resorbed mandibles.     

Surgical and prosthetic treatment of the atrophic mandible

Two vestibuloplasty methods and a muscle-formed method for improving the retention and stability of complete mandibular dentures were compared in 19 edentulous patients with advanced mandibular bone resorption. The resorptive changes in the alveolar crest and any relapse in the extended vestibule after surgery were monitored for 2 yr. Simultaneous production of the first new complete dentures, to which the labial plate is added during the surgical procedure, and firm circummandibular fixation during primary healing will guarantee the best surgical and prosthetic results. This order of treatment also eliminates unnecessary surgical procedures. A muscle-formed method for extending the baseplate of a complete mandibular denture was found to be a useful alternative for patients with highly advanced mandibular bone resorption.     

Tooth spaces in and prosthetic treatment received by the middle-aged and the elderly in Hong Kong

Abstract The purpose of this study was to describe the state of the dentition of middle-aged and elderly Chinese in Hong Kong in terms of teeth present, tooth spaces, and prosthetic treatment received. In an oral health survey conducted in 1991 in Hong Kong, a sample of 372 35–44-yr-olds and 537 noninstitutionalized 65–74-yr-olds was interviewed and clinically examined. In all dentate subjects, each tooth was scored for the presence/absence of that tooth, a tooth space of 5.5 mm which had not been treated, or the presence of a denture or pontic replacing that tooth. Each denture was assessed according to a set of criteria. None of the 35–44-yr-olds were edentulous and the mean number of teeth present was 27.5. About 40% of the third molars and about 35% of the mandibular first molars were missing. For only 1% of the missing teeth had space closure resulted in missing teeth not being recorded as tooth spaces or treated tooth spaces. Overall, 72% of the 35–44-yr-olds had no prosthesis. 17% had a bridge or bridges, 12% had a denture or dentures, and 1% had both. Of the 65–74-yr-olds, 12% were edentulous, and the dentate subjects had a mean number of 17 teeth present. About 70% of the molars were missing. Overall, only 29% of the elderly had no prosthesis, 52% had a denture or dentures, 33% had a bridge or bridges, and 13% had both. Only 35% and 28%, respectively, of the middle-aged and elderly denture wearers had no complaint about their dentures. There were more assessed problems in the dentures of the elderly than in those of the younger adults, over one-third of the partial dentures and half of the mandibular complete dentures being unstable and unretentive.     

Non‐submerged osseointegrated dental implants with ball attachments supporting overdentures in patients with mandibular alveolar ridge atrophy. A short‐term follow up.

Non‐submerged, hollow screw ITI‐Bonefit dental implants with ball attachments supporting overdentures were used as alternative treatment to combined vestibulo‐lingual‐plasty with free split‐thickness skin graft and removable dentures in 40 consecutive patients with mandibular alveolar ridge atrophy. One hundred and fifty‐six non‐submerged fixtures were installed. Ball attachments were mounted on the fixtures and implant‐supported overdentures inserted 34 months after fixture installation. The observation period after implant activation and prosthesis insertion varied from 1 to 3 years with a median observation period of 2 years. The overall success rate of individual implants was 99%(155/156). The prosthesis function rate was 100%(40/40). The 1‐year success rate of individual implants was 99%(155/156) with a prosthesis function rate of 100% 40/40. No persistent surgical, periodontic or prosthodontic complications were observed. The results indicate that non‐submerged osseointegrated ITI‐Bonefit dental implants with ball attachments supporting overdentures can be a successful alternative to combined vestibulo‐lingualplasty with free split‐thickness skin graft and removable dentures, and as successful as the use of submerged dental implants.     

Fractures of the atrophic, edentulous maxilla during Le Fort I osteotomy

The incidence of unfavorable fractures of the maxilla during Le Fort I osteotomy was compared between patients with atrophic, edentulous maxillae and patients with normal dentate maxillae. Unfavorable fractures frequently occurred in atrophic, edentulous maxillae. The most common maxillary fracture involved the junction of the horizontal plate of the palatine bone and posterior part of the maxilla. Prevention strategies and treatment options are discussed.     

Surgical and prosthetic treatment for microphthalmia syndromes

Our aim was to evaluate the long-term outcomes of prosthetic treatment and orbital expansion in the management of microphthalmia syndromes. We did a retrospective single-centre study of all cases of microphthalmia treated between 1989 and 2010. The patients were divided into three groups: isolated microphthalmia, microphthalmia associated with micro-orbitism, and complex microphthalmia syndrome. To evaluate the results a score was computed for each patient by assessing the length of the palpebral fissure, the depth of the conjunctival fornix, and local complications together with an evaluation of the satisfaction of patients and their families.     

The rehabilitation of oral defects by osseointegrated implants

Abstract. So far, preprosthetic surgery for oral defects improved prosthetic retention problems for only a limited amount of time and led to many side-effects. The alternative offered by the osseointegration technique developed by P.–I. Brånemark changed the concept of preprosthetic surgery dramatically. By means of a few permucosal titanium screws, bridges or overdentures can be retained even in cases of advanced jaw bone resorption. When the latter is extreme, an autologous free bone graft fixed by means of self-tapping titanium implants can offer the necessary support for sometimes elaborate prosthetic reconstructions. The marginal bone loss around Brånemark implants is very limited after a 1st year of bone remodelling, even when an autologous transplant has been used.     

Clinical application of tissue-engineered transplants. Part I: mucosa

OBJECTIVES: The study series aims at testing the feasibility of the clinical application of tissue-engineered oral mucosa. The preliminary results were gathered over a period varying from 6 months to 12 years depending on the surgical method. METHODS: Tissue-engineered oral mucosa was used to cover defects in various surgical procedures like vestibuloplasty (n=42), freeing of the tongue (n=10), prelaminating the radial flap (n=5) and reconstruction of the urethra (n=16). In all interventions small samples of oral mucosa were harvested, cut into small pieces, resuspended in culture medium and seeded into a culture flask. Cultured keratinocytes were transferred onto membranes which then were used to cover mucosal defects in the oral cavity. RESULTS: To gain a graft of 15 cm(2) size a mucosa biopsy of 4-8 mm(2) and 40 ml autologous patients serum is needed. Tissue-engineered oral mucosa was applied successfully in all four surgical methods. Six months after transplantation a regular epithelial layering with a histological delimitation of the stratum, epithelial crest and a strong basal membrane appeared. According to the reception site the tissue engineered oral mucosa differentiated in several ways. CONCLUSION: Tissue-engineered oral mucosa fulfils the requirements for clinical routine. With view to healing time and outcome it does not appear to be superior to regular harvested oral mucosa transplants. Because of a smaller harvesting defect and primary wound closure at the actual operation site the patients' convenience is increased. Thus this method reduces morbidity and advances the quality of life.     

Immediate loading in the completely edentulous mandible: technical procedure and clinical results up to 3 years of functional loading

Objectives: This prospective mono‐center study describes a clinical technique to provide dental implants with a temporary cross‐arch cantilever bridge functionally loaded on the day of fixture insertion and discusses the 3‐year follow‐up of four to six machined surface Brånemark implants installed in the interforamina area. Material and methods: Ninety Brånemark implants were installed in 18 edentulous mandibles. Five patients were heavy smokers and one had Down syndrome. The day of surgery, a 10 unit provisional glassfiber‐reinforced cantilever bridge was installed. The final 12 unit bridge was in place after an average of 144 days (range 10–332). Bone‐to‐implant level was assessed radiologically from the day of surgery up to 3 years. Results: Two out of five fixtures were lost within 3 months in the Down syndrome patient but the provisional bridge continued to function on the three remaining implants until the patient was successfully reoperated. Another implant was lost after 11 months due to a non‐detected fracture in the metal framework, resulting in overloading of the cantilever part. As no additional losses occurred during the follow‐up time (range 57–26 months), the total failure rate is 3/91 (3.3%). Seventeen of the 18 patients are loading their implants more than 3 years and nine have moved beyond the 4‐year period. Average bone remodelling as measured on the apical radiographs from 12 patients at 0, 12 and 36 months revealed a statistically significant bone loss from the initial 0.1 mm [standard deviation (SD) 0.2; range 0–0.7] toward 1.8 mm (SD 0.2; range 1.6–2.2) during the first year of function. (Wilcoxon's signed rank test; P<0.002). After 3 years, no further significant bone loss occurred. Conclusion: This 3‐year study shows that machined surface Brånemark implants can be immediately loaded with cross‐arch cantilever bridges with an average bone‐remodelling pattern indicative of a steady state after 1 year of loading.     

Inequalities in prosthetic rehabilitation among elderly people: the importance of context

Giordani JMA, de Slavutzky SMB, Koltermann AP, Pattussi MP. Inequalities in prosthetic rehabilitation among elderly people: the importance of context. Community Dent Oral Epidemiol 2011; 39: 230–238. © 2010 John Wiley & Sons A/S Abstract – Objective: It has been demonstrated that social, economic, and environmental factors may influence individuals’ oral health conditions, particularly among vulnerable groups such as elderly people. The aim of this study was to investigate the association between contextual factors and the need for full dental prosthesis among elderly people. Methods: This was a cross‐sectional population‐based epidemiological study of multilevel nature, with two levels of analysis: individual and contextual (municipal). Data at the individual level were obtained from oral clinical examinations (WHO criteria) in 5349 individuals aged 65–74. Data at the contextual level were obtained from the United Nations Development Program for the 250 Brazilian municipalities participating in the survey. The outcome was the need for a full dental prosthesis for at least one arch. Exposures at the contextual level included socioeconomic, demographic, and dental service data. Data analysis used multilevel logistic regression. Results: After controlling for individual socioeconomic, demographic, and dental service variables, the chance of needing full prosthesis was higher in municipalities with lower educational levels than in better‐off ones (OR 1.57; 95% CI: 1.09–2.27) and lower in municipalities with fewer dentists (per capita) (OR 0.71; 95% CI: 0.52–0.97), compared to those with more dentists. Conclusion: This study can contribute to the identification of priority municipalities, helping healthcare authorities and communities to formulate equitable public oral healthcare policies that improve the quality of life for this population.     

Surgical management of the atrophic edentulous ridge--a prosthetic view.

The vast majority of edentulous patients manage to wear complete dentures with relative ease. There are however a small group of patients described as "Denture Cripples" by Hopkins, Stafford and Gregory (1980), for whom the provision of complete dentures using conventional means has proved impossible. Clinical examination usually reveals marked atrophy of the alveolar ridge, the prominence of sharp bony ridges and an atrophic denture bearing mucosa. The patient complains of loose, painful dentures and an inability to masticate a normal diet. The patients can often be helped by correcting errors on their presenting dentures or by minor surgical procedures such as frenectomy or smoothing sharp bony ridges. Other patients present with such extreme ridge atrophy that major surgery may need to be considered. This paper reviews three types of surgery commonly used to help the prosthetist rehabilitate the patient, namely vestibuloplasties, ridge augmentations and implants.     

Oral health-related quality of life in tumour patients treated with patient-specific dental implants

Dental rehabilitation after surgically acquired bone deficiency related to tumour treatment remains a challenge. The insertion of patient-specific implants geared to the contour of the remaining bone is a feasible method of supporting fixed or removable dentures. As oral health-related quality of life (OHRQoL) is of great interest in these cases, 12 individuals treated with patient-specific implants for severe bone deficiency were surveyed and their Oral Health Impact Profile (OHIP) scores after dental rehabilitation were evaluated. The OHIP-G53 questionnaire was used to measure overall treatment outcomes. The distribution of OHIP sum-scores for participants treated with patient-specific implants was almost homogeneous when compared to those cited in the literature for patients treated with conventional dental implants. OHIP items related to functional impairment and physical pain showed the highest scores (occurring occasionally), and financial loss related to treatment was frequently stated. Moreover, higher scores were detected in almost all OHIP dimensions for participants with patient-specific implant-supported removable dentures. Conversely, those treated with patient-specific dental implants and fixed dentures showed lower psychosocial impact scores and equal or superior OHRQoL. Hence, patient-specific dental implants, especially combined with fixed dentures, can lead to a positive OHRQoL in patients with severe bone deficiencies related to tumour therapy.     

不同口腔修复材料对磁共振成像的影响

目的:收集临床常用的口腔修复材料在磁共振中的影像数据,分析其伪影对磁共振检查和诊断的影响.方法:3名分别携带有纯钛种植体,钴铬桩冠烤瓷牙冠以及二氧化锆全瓷冠修复患者行磁共振扫描,磁共振仪磁场强度为1.5 T,采用FSE-T1WI序列,观察和分析伪影图像,评估口腔修复材料对磁共振诊断的影响. 结果:3种口腔修复体在磁共振扫描中均存在不同程度的伪影,钴铬修复体产生的伪影面积较大,纯钛修复体其次. 伪影图像呈圆形或椭圆形,沿修复体边缘向周围扩散,相关区域部分图像扭曲变形,且在钴铬及纯钛修复体伪影周围产生高亮度线圈样影像;二氧化锆全瓷冠伪影面积最小,仅对其周围骨组织成像有一定影响. 结论:不同材质口腔修复体在磁共振扫描中均可产生不同程度的伪影,但其波及范围有限,对较远处组织成像无明显干扰.在不摘除固定修复体的同时,患者可安全接受磁共振检查.     

Fabrication of a Surgical Stent for Bilateral Tuberosity and Mandibular Alveolar Reduction

A technique for constructing a single surgical stent to direct bilateral preprosthetic maxillary tuberosity reductions and mandibular alveolectomies is presented. The stent is fabricated using unaltered articulated definitive casts. The stent allows the oral surgeon to replicate the desired vertical dimension of occlusion for a thorough assessment of the sufficiency of the surgical revisions. The situation illustrated is unique, in that preoperatively, the patient's maxillary tuberosities were situated inferior and medial to their ipsilateral retromolar pads.     

Palatonasal Recess on Medial Wall of the Maxillary Sinus and Clinical Implications for Sinus Augmentation via Lateral Window Approach

Background: Anatomic variations of the maxillary sinus determine the degree of difficulty in performing sinus augmentation. Whereas some variations, e.g., the septum and morphology of the sinus, have been extensively studied, the structure of the medial wall has never been investigated. The aims of this study are to measure the location and angulation of the palatonasal recess (PNR) on the medial wall and identify risk sites that are related to the shape of the PNR. Methods: Cone‐beam computed tomography (CBCT) scans were screened from the University of Michigan School of Dentistry database. Edentulous sites with <10 mm between the floor of the maxillary sinus and the alveolar crest were selected. The residual ridge height (RH), the distance between the PNR and the alveolar crest, and the angulation of the PNR were measured on the selected sagittal planes. The percentage of sites (risk sites) with recesses that were <90°and <15 mm from the alveolar crest was calculated. The PNR location and angulation were compared among premolar and molar edentulous sites. Results: Two hundred seventy‐four sites were studied. The mean ± SE PNR location was 14.2 ± 2.8 mm, 13.1 ± 2.2 mm, and 12.5 ± 2.5 mm for the second premolar, first molar, and second molar sites, respectively, with significant differences between the second premolar and second molar sites. The mean PNR angulation was 109.8° ± 25.3°, 121.6° ± 22.1°, and 144.9° ± 23.1° in the corresponding sites, with significant differences among the site groups. The respective percentages of risk sites were 15%, 8.2%, and 2.4% in the second premolar, first molar, and second molar sites. Conclusions: Maxillary sinuses with acute‐angled PNRs might present a challenge for performing sinus augmentation. Therefore, this anatomic structure should be carefully evaluated.