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1.
Morphologic Characteristics of Bony Edentulous Jaws   总被引:1,自引:0,他引:1  
PURPOSE: The objective of this study was to examine bone tissue characteristics of edentulous arches and residual ridges in different regions of the human jaws. MATERIALS AND METHODS: For the study, 24 maxillary and 99 mandibular completely edentulous dry specimens were examined macroscopically and by linear and caliper measurements. Width and length of the edentulous arches were registered from the molar regions to the crest of the incisor zone. Residual ridges were quantified at the incisor, premolar, and molar regions. RESULTS: Arches and ridges varied in size and shape. A trabecular bone track was present at the edentulous surface. In the maxillary arch, trabecular tissue was external to the cortical palatal vault, and in the mandible, the trabecular bony stretch was inside the cortical plates along the entire edentulous surface of the jaw. Of the ridges, 38% were thin knife-edged. In the maxilla, bone resorption was centripetal, and the crest of the edentulous arch was external to the osseous base of the cranium. In the mandible, resorption was centrifugal, forming an edentulous crest lingual to the mental protuberance anteriorly and to the mandibular base posteriorly. This discrepancy produced a reverse horizontal overlap of the residual crests, where the edentulous maxilla was at the same level or internal to the facing edentulous mandible. CONCLUSIONS: This study, performed on 123 human edentulous dry bone specimens, indicates that the edentulous arch and the residual ridge take many forms. At the occlusal surface of the edentulous jaw a trabecular track is the remaining scar after tooth extraction. To accommodate an entire metal osseointegrated implant within the residual bone volume, crest reduction and bone grafts may be required as preprosthetic surgical measures. After tooth loss, maxillary resorption was centripetal and apical, whereas mandibular resorption was centrifugal and also apical, resulting in a reversed horizontal relationship in fully edentulous subjects.  相似文献   

2.
目的 观察无牙颌患者在牙槽嵴骨吸收程度不同的情况下下颌中性区外形的变化,以期寻找恰当的义齿磨光面设计.方法 选择20例无牙颌患者,根据患者上下颌弓关系,分为3组.第一组:牙槽嵴轻度吸收患者:第一类无牙颌,上下颌弓关系正常,共6例;第二组:牙槽嵴中度吸收患者:第二类无牙颌,上下颌弓关系正常,共7例;第三组:牙槽嵴重度吸收患者:第三类无牙颌,上下颌弓关系为反(牙合),共7例.通过患者充分主动的肌功能整塑,较准确地形成中性区外形,以此作为义齿磨光面,使用三维牙颌模型激光扫描仪对上下颌模型及磨光面进行三维激光扫描和重建.分别在双侧磨牙区和前磨牙区作垂直于磨光面轴线的垂面,将磨光面及上下颌模型一并切开,得到截面.观察截面形态,并在各截面上测量下颌舌侧磨光面外形曲线拟合直线与(牙合)平面所成的角度.结果从截面形态可见,第一组患者颊舌侧磨光面形态均为凹形;第二组患者颊舌侧磨光面形态均未见明显凹陷,为略凸或直形;第三组患者磨光面形态呈倾斜状.第一、二、三组患者下颌舌侧磨光面外形曲线拟合直线与(牙合)平面所成的角度分别为(80.40±3.51)°、(90.38±2.71)°和(96.59±5.00)°.结论 牙槽嵴骨吸收程度不同,下颌中性区外形有所不同,提示临床上在设计义齿磨光面外形时,应考虑牙槽嵴的吸收程度及上下颌弓关系.  相似文献   

3.
PURPOSE: This anatomic study was undertaken to examine the effects of atrophy on bone quantity and quality in the mandibular interforaminal region. MATERIALS AND METHODS: Three sections were made from each jaw studied, and each section was measured by means of a morphometric software program (Artma-Biomed, Vienna, Austria). The mandibular specimens were grouped according to the classification of Cawood and Howell and also according to that of Lekholm and Zarb. RESULTS: The macromorphometric measurements revealed that mandibular atrophy may cause the loss of up to 60% of the original bone mass. As the maximum width remained relatively consistent in all jaw sections, it can be assumed that the reduction in total area of each jaw section results from a reduction in mandibular height. The compact and cancellous bone portions were equally affected by resorption. The assessment of bone quality showed that most mandibles displayed a thick cortical compartment, especially inferiorly and lingually, with variations in the amount of cancellous bone. There was a clear predominance of bone types 2 and 3. DISCUSSION AND CONCLUSION: The interforaminal region of the mandible appears to be the site of choice for implantation, since it can be expected that the bone structure is well suited to provide the necessary stability even in severely atrophic mandibles. As the degree of alveolar ridge resorption does not depend on the patient's age but on the time elapsing postextraction, implants should be placed as soon as possible after tooth loss in order to avoid excessive resorption.  相似文献   

4.
Residual ridge resorption in the mandible after tooth loss may lead to worsening of complete denture stability and to various subjective complaints. The aim was to evaluate the association between radiologically assessed residual ridge resorption in the mandible, clinically assessed stability of lower complete denture and subjective complaints among elderly denture wearers. The study population consisted of 326 (115 men and 211 women) edentulous subjects aged 60-78years, all of whom were wearing complete dentures in the mandible. Data on subjective complaints were obtained from questionnaires and interviews. Denture stability was assessed clinically. Residual ridge resorption was analysed from panoramic radiographs. The results showed that women were significantly more often satisfied with their lower dentures and reported fewer problems with eating than men. They also had significantly more often residual ridge resorption than men. Among women, residual ridge resorption was significantly associated with poor chewing ability, low satisfaction with dentures and poor denture stability. Among men, residual ridge resorption did not associate with subjective complaints or denture stability. Poor satisfaction with dentures associated significantly with poor denture stability in both genders. In conclusion, these results highlight the importance of denture maintenance treatment. As the extent of residual ridge resorption in the mandible was the most important factor that increased dissatisfaction with lower complete dentures, it is also important to inhibit the progression of resorption by preventing tooth loss or by using implant-retained dentures.  相似文献   

5.
The residual alveolar ridge resorption is inevitable with aging. The purpose of the study was to determine and compare differences in the vertical measurements of jaw bones in elderly dentate and edentulous subjects. The study sample included 51 elderly dentate subjects and 59 edentulous subjects. The panoramic radiographs were used to quantify the reduction in the alveolar ridges at 5 sites in each jaw. There were significant differences between elderly dentate and edentulous subjects in maxilla and mandible. The percentage reduction in the vertical height of edentulous subjects as compared to dentate subjects ranges from 29% to 39%. The reduction in the heights was greater in mandible than in maxilla in both the study groups. The vertical measurements were significantly greater in men than in women in maxilla and the mandible. Vertical heights of maxillary and mandibular jaw bones are important factors in planning complete denture and the implant supported prosthesis. Further studies would be necessary to determine the region specific resorption of jaw bones and its association with the duration of denture wear in edentulous subjects.  相似文献   

6.
Aim: To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket. Material and methods: Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re‐entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S‐OC), (ii) the horizontal residual gap (S‐IC), (iii) the vertical residual gap (R‐D) and (iv) the vertical position of the bone crest opposite the implant (R‐C). Results: It was demonstrated that (i) the S‐OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco‐lingual implant position influenced the amount of buccal crest resorption. Conclusions: Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing. To cite this article:
Tomasi C, Sanz M, Cecchinato D, Pjetursson B, Ferrus J, Lang NP, Lindhe J. Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis.
Clin. Oral Impl. Res. 21 , 2010; 30–36.  相似文献   

7.
Atrophy of the lower jaw is essentially a manifestation of vertical bone resorption and must be treated in a compensatory manner. Animal experiments have shown the value of the bioactive glass ceramic Ceravital as a bone replacement material. After box-shaped or step-shaped osteotomies, we perform interpositional plastic operations with glass ceramic in order to augment the atrophied human lower jaw. Results, advantages and dangers of the method are shown in 12 patients.  相似文献   

8.
The aim of the present study was to evaluate the effect of using mandibular cortical bone grafts covered with e-PTFE membranes for maxillary alveolar ridge augmentation, in comparison with the use of mandibular cortical grafts alone. The experiment was carried out in 20 rats. At one side of the maxillary jaw, the edentulous alveolar ridge between the incisor and the first molar was augmented by means of an autogenous mandibular bone graft, which was fixed with a titanium microimplant and covered with a Teflon membrane. The contralateral side, serving as control, was treated the same way, except for the placement of a membrane. Histological analysis at 15, 30, 60 and 90 days after surgery demonstrated that, in situations where the membrane was not exposed to the oral cavity during healing, the mandibular bone grafts presented no resorption and were in continuity with the maxillary bone at the recipient site. In situations where the membrane had become exposed, however, the bone grafts presented extensive resorption and lack of continuity with the bone at the recipient site. These latter findings were similar to those made at the non-membrane-treated side. The results indicate that the volume of autogenous bone graft used for alveolar ridge augmentation can be retained by covering the graft with a membrane, provided that the membrane is properly adapted and is kept covered with mucosa during healing.  相似文献   

9.
This study aimed to compare the influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T6 m), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar‐implant‐retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.  相似文献   

10.
Abstract – This prospective clinical analysis reports on the use of coral granules in alveolar ridge preservation procedures in a population of young, growing patients. The sample consisted of 21 patients, 12 females and 9 males, with a mean age of 13.6 years. These 21 patients had 48 dento‐alveolar defects suitable for augmentation with coral granules, and were followed clinically and radiographically for 3–7 years after augmentation. There were two areas of augmentation: 17 defects in the anterior maxilla resulted from traumatic tooth loss, and 31 defects in the posterior maxilla and mandible resulted from the extraction of ankylosed retained primary molars with no permanent succedaneous teeth. Between 1–2 ml of coral granules were implanted into the alveolar bone defects left by the extraction of teeth in both the areas. This was in order to preserve the remaining edentulous ridge from further alveolar ridge resorption. The goal of the procedure was to preserve the alveolus so that in the future, a dental implant could be placed to replace the missing tooth, after jaw growth had stopped, without the need for a bone graft. The coral granules appeared to be totally replaced by the host bone on follow‐up clinical and radiographic examinations. The two areas of the jaws behaved quite differently. In the anterior maxilla, where tooth loss was secondary to trauma, the coral granules restored the alveolar ridges temporarily. However, over the years of follow‐up in this study, the coral granules failed to provide sufficient bone to support the placement of a dental implant without using a bone graft in 14 of the 17 defects or 82.4% of sites. In the posterior maxilla and mandible, where tooth loss was due to the elective removal of ankylosed primary molars, 29 of the 31 defects or 93.5% of sites were successful as they were able to support the placement of an osseo‐integrated dental implant without the use of a bone graft. The alveolar sparing technique was more successful in maintaining an alveolar ridge sufficient for the placement of a dental implant without bone grafting in the posterior maxilla and mandible, where tooth loss was secondary to the elective removal of ankylosed deciduous molars than in the anterior maxilla, where tooth loss was secondary to trauma. Coral granules seem to be more suitable in the posterior maxilla and mandible where there were ankylosed deciduous teeth and congenitally absent permanent teeth than in the traumatized anterior maxilla. In successful sites, coral granules can spare the alveolus from residual ridge atrophy or resorption, obviating the need for a bone graft. This reduces patient morbidity, as a second surgical donor site is avoided because bone graft harvesting is made unnecessary.  相似文献   

11.
MATERIAL AND METHOD: We present a retrospective analysis of periodontal tissue reactions and clinically relevant phases of permanent tooth eruption and deciduous tooth resorption after half a year of orthodontic tooth movement in the upper and lower jaw of a deceased male (age 9 years 3 months). Specimens of the horizontal plane (lower jaw) and sagittal plane (upper jaw) were prepared by the ground microsection technique without prior decalcification. RESULTS: Histologically, reactions in the periodontal ligament presented as characteristic appositional/resorptive metaplastic processes in the areas of tension and pressure, with side effects such as root resorption and periodontal necrosis being only minor. In the upper jaw, an erupting permanent canine was closely associated with the tooth germ of the first premolar. Resorptive follicle activity had resulted in extensive erosion of the interradicular bone and root resorption in the area of the first premolars. CONCLUSION: These findings suggest that it might prove useful to take critical topographic findings as parameters for differential therapeutic decisions. Follicle-driven deciduous tooth resorption presenting partly as resorption lacunae and partly with linear characteristics was accompanied by resorptive/appositional remodeling of the alveolar socket as well as regressive changes in the supracrestal fibers of the marginal gingiva.  相似文献   

12.
Abstract: This study investigated the change over time in the area of the posterior mandibular residual ridge in patients wearing either i) mandibular overdentures stabilised by two implants (Brånemark System; Nobel Biocare, Göteborg, Sweden) connected by a bar, or ii) mandibular fixed cantilever prostheses stabilised on five or six implants. Proportional measurements were made in order to compare the area of the residual ridge with an area of bone uninfluenced by resorption. Measurements were made by digitising tracings of panoramic radiographs that were taken shortly after implant insertion and up to seven years later. With the use of overdentures, the posterior bone area index reduced by a mean of 1.1% per annum, while a mean bone area index increase of 1.6% per annum was demonstrated in association with fixed prostheses. A multiple linear regression model was fitted to predict the change in posterior area from type of prosthesis, gender, age, years of edentulism and initial height of the mandible. The model was only significant for initial height of mandible (P = 0.04) and type of prosthesis (P = 0.0001). In conclusion, patients rehabilitated with implant‐stabilised mandibular overdentures demonstrated low rates of posterior mandibular residual ridge resorption, while patients rehabilitated with implant‐stabilised mandibular fixed cantilever prostheses demonstrated bone apposition in the same area.  相似文献   

13.
Location of the mandibular canal within the atrophic mandible   总被引:1,自引:0,他引:1  
In 43 edentulous, lower jaw halves, sections were carried out in the area between the mental foramen and the third molar. The relative changes in the location and course of the mandibular canal which are caused by atrophy were analysed. For this purpose, the mandibles were classified according to so-called residual ridge orders which describe the different stages of alveolar ridge resorption.The following findings were obtained: The distance between the mandibular canal and the lingual and buccal external border does not change in any stage of the atrophic process, i.e. it remains conspicuously constant. However, the distance between the mandibular canal and the cranial and caudal borders of the body of the mandible partly changes to a statistically highly-significant extent, the distance between the canal and the atrophic alveolar ridge being affected more strongly than that between the canal and the base of the mandible. These changes were most clearly pronounced in the area of the first molar.  相似文献   

14.
本文通过曲面体层X线摄片测量,对男女两组共46例无牙颌患者下颌角皮质骨厚度与剩余牙槽嵴高度进行相关性研究,结果发现,下颌角皮质骨厚度与剩余牙槽嵴高度呈显著正相关关系(男女两组均为P<0.01);男性组下颌角皮质骨厚度及剩余牙槽嵴高度虽均大于女性组,但差异无显著性意义(P>0.5)。该结果提示全身性因素对剩余牙槽嵴吸收起主要作用。  相似文献   

15.
Background: The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze‐dried bone allograft (FDBA) in non‐molar extraction sockets. Methods: Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical versus cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17 to 21 weeks (average: 18.2 weeks), and a 2‐mm‐diameter core biopsy was obtained before implant placement. Histomorphometric analysis was performed to determine percentage of new bone formation, residual graft material, and non‐mineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement. Results: There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (P = 0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group compared with the cancellous FDBA group (P = 0.019). A significantly greater percentage of non‐mineralized CT/other material was found in the cancellous FDBA group compared with the cortical FDBA group (P = 0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group. Conclusions: This is the first reported study to compare the histologic changes following tooth extraction with ridge preservation in humans using cortical versus cancellous FDBA. There were no differences in the percentage of new bone formation between the groups.  相似文献   

16.
Pure trigeminal motor neuropathy is a very unusual disease that is characterized by trigeminal motor paralysis without trigeminal sensory disturbances and without the involvement of the other cranial nerves. We report a case of pure trigeminal motor neuropathy in a 70-year-old woman. The diagnosis was based on the results of clinical, electromyographic, and radiologic examinations. Only the motor branch of the left trigeminal nerve was damaged. Atrophy of the left-side masticatory muscles and jaw resulted in facial asymmetry. Magnetic resonance imaging (MRI) of the head and face did not detect any pathologic lesion, with the exception of atrophy and fatty infiltration of the muscles innervated by the left trigeminal motor nerve. The etiology of the patient's pure trigeminal motor neuropathy was undetermined. Patients with suspected trigeminal motor neuropathy should undergo MRI of the head and face to evaluate the sequelae of denervation and to detect an intracranial or extracranial lesion.  相似文献   

17.
Objective: The G/BBB syndrome is an X‐linked recessive disorder characterized by eye anomalies, laryngotracheoesophageal cleft, congenital heart disease, genitourinary anomalies and gastrointestinal disorders. Patients may also present cleft lip and palate, high‐arched palate and thin upper lip. This study aimed to investigate the occurrence of tooth abnormalities and soft tissue changes in patients with G/BBB syndrome. Design: Cross‐sectional. Subjects and methods: Twenty‐one patients with G/BBB syndrome were analyzed as to the presence of tooth abnormalities and soft tissue alterations. Main outcome measures: The prevalence of tooth agenesis and supernumerary teeth was compared to patients without morphofunctional alterations, matched for gender and age. Results: All patients had complete cleft lip and palate; 95.23% of patients presented tooth abnormalities, mainly hypoplastic alterations, with predominance of alterations of number, followed by alterations of structure, shape and position. The frequency of tooth agenesis and supernumerary teeth was significantly higher compared with the control group; 11 patients presented incisiform supernumerary teeth in the mandibular anterior region. Ankyloglossia was observed in 11 of 21 patients. Conclusion: The presence of mandibular anterior supernumerary teeth and ankyloglossia should be investigated in the clinical evaluation of patients with suspected diagnosis of the G/BBB syndrome.  相似文献   

18.
Objective: To compare ridge alterations after flap and flapless tooth extraction in the vertical and horizontal dimension in the dog model. Material and methods: This study was carried out on five Beagle dogs. Four extractions were performed in the lower jaw of each dog (two per side. Pm3, Pm4). At the time of tooth extraction, flap surgery was performed on one side (control group). On the contra‐lateral side, a flapless extraction was performed (test group). Mesial sockets were left untreated on both sides. After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. Results: Ten samples were evaluated on each group. The vertical difference in height between the buccal and lingual crest was 1.48 mm for the flap, and 1.22 mm for the flapless group. The horizontal dimension of the ridge was 4.41 mm (at 1 mm from the crest), 5.72 mm (at 3 mm from the crest) and 6.67 mm (at 5 mm form the crest) in the flap group. In the flapless group, the measurements were 4.5, 5.58 mm and 6.44 at 1, 3 and 5 mm from the crest, respectively. Conclusion: Evaluating ridge alterations in the vertical and horizontal dimension after 3 months of healing following tooth extraction, results for the flap and the flapless group were very similar. To cite this article:
Blanco J, Mareque S, Liñares A, Muñoz F. Vertical and horizontal ridge alterations after tooth extraction in the dog: flap vs. flapless surgery.
Clin. Oral Impl. Res. 22 , 2011; 1255–1258.
doi: 10.1111/j.1600‐0501.2010.02097.x  相似文献   

19.
The study investigated whether chronic TMD patients with disc displacement with reduction (DDR), performing non‐assisted maximum jaw movements, presented any changes in their mandibular kinematics with respect to an age‐matched control group. Moreover, it was examined whether jaw kinematics and a valid clinic measure of oro‐facial functional status have significant associations. Maximum mouth opening, mandible protrusion and bilateral laterotrusions were performed by 20 patients (18 women, 2 men; age, 18–34 years) and 20 healthy controls (17 women, 3 men; age, 20–31 years). The three‐dimensional coordinates of their mandibular interincisor and condylar reference points were recorded by means of an optoelectronic motion analyser and were used to quantitatively assess their range of motion, velocity, symmetry and synchrony. Three functional indices (opening–closing, mandibular rototranslation, laterotrusion – right and left – and protrusion) were devised to summarise subject's overall performance, and their correlation with the outcome of a clinical protocol, the oro‐facial myofunctional evaluation with scores (OMES), was investigated. TMD patients were able to reach maximum excursions of jaw movements comparable to healthy subjects’ performances. However, their opening and closing mandibular movements were characterised by remarkable asynchrony of condylar translation. They had also reduced jaw closing velocity and asymmetric laterotrusions. The functional indices proved to well summarise the global condition of jaw kinematics, highlighting the presence of alterations in TMD‐DDR patients, and were linearly correlated with the oro‐facial functional status. The jaw kinematic alterations seem to reflect both oro‐facial motor behaviour adaptation and a DDR‐related articular impairment.  相似文献   

20.
Severely atrophic ridges provide decreased retention, support, and stability and pose a clinical challenge to the success of complete denture prostheses. Extreme ridge resorption also increases the interridge distance. Restoration of the vertical dimension and esthetics thus demands increased height of the prosthesis and in turn leads to an increase in prosthesis weight. Reducing the weight of the denture enhances stability and retention and reduces further resorption of the jaw, thereby favoring the prognosis of the denture. This report describes the rehabilitation of an edentulous patient with resorbed maxillary and mandibular ridges and an increased interridge distance using simplified techniques of fabricating hollow dentures.  相似文献   

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