Alveolar Ridge Resorption Research Articles

Bone loss and teeth

Loss of teeth results in irreversible alveolar bone resorption, and untreated dental disease causes alveolar bone lysis that ultimately leads to loss of teeth. In addition to anchoring the teeth in the alveolar ridge, the maxillary and mandibular bone allows dental restoration procedures, such as construction of root-supported implants, fixed dentures, or removable dentures. However, the functional and cosmetic results depend on the quantity and quality of the maxillary or mandibular bone, which can be affected by many normal and abnormal processes. The alveoli are particularly fragile and labile. Changes in alveolar bone vary considerably across individuals and depend directly on local factors. Many studies have investigated associations between alveolar bone status and bone mass at other skeletal sites. These studies focused chiefly on the course of parodontal disease, alveolar ridge resorption after tooth extraction, and density differences across various mandibular sites. They produced conflicting results, probably because of differences in measurement methods. Measurement sites and methods should be standardized to ensure that reliable and comparable data are obtained. To date, there are few reliable methods for obtaining quantitative measurements of bone mineral content in maxillary and mandibular bone.

顎堤条件からみたリンガライズドオクルージョンの選択

Lingualized occlusion is applied to patients with alveolar ridge resorption, and it is considered that this occlusion is functionally useful and should be applied to cases with alveolar ridge resorption. However, selection criteria supported by evidence for what conditions of the alveolar ridge lingualized occlusion should be selected do not exist. For that reason, we conducted an investigation on choosing lingualized occlusion. As a result, no differences were noted in subjects with a good alveolar ridge condition while a sufficient lingualized occlusion effect was obtained in subjects with a poor alveolar ridge condition, suggesting that efficient mastication could be attained. The following indexes were examined as the criteria for applying lingualized occlusion: The ratio of the residual alveolar ridge should be less than approximately 0.5, in which the distance between the inferior border of the mental foramen and the superior border of the mandibular bone should be less than half the distance between the inferior border of the mental foramen and the inferior border of the mandibular bone. The supporting area of the denture base should be less than approximately 2,000 mm(2). Though the effect can be expected when applying lingualized occlusion under these criteria, they are one standard, and cannot be applied in all cases. In clinical cases, it is important to grasp the local and the whole-body conditions of the patient in order to choose denture occlusion.

Changes caused by a mandibular removable partial denture opposing a maxillary complete denture

Although many advances have been made in denture prosthetics, the great problem is still with us: coping with the resorption of the residual alveolar ridge and managing or preventing the secondary soft tissue changes brought on by bone loss.

Preservation of ridge dimensions following grafting with coral granules of 48 post‐traumatic and post‐extraction dento‐alveolar defects

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.

Effect of smoking on resorption of residual alveolar ridges in complete denture wearers

Based on literature data it is obvious that there is a connection between smoking and periodontal diseases. Alveolar bone loss increases with smoking. Tobacco smoking affects the proportion of subgingival bacterial flora by influencing oxidoreduction potential of dental plaque and thus making conditions for development of anaerobic bacteria. According to some researchers, smoking affects the mineral component of bone tissue. Orthopantomograms show higher level of alveolar bone loss in smokers than in nonsmokers with the same level of oral hygiene. The aim of this study was to establish if smoking affects alveolar bone loss in complete denture wearers. Our clinical investigation included 60 patients of both sexes (30 smokers and 30 nonsmokers) all complete dentures wearers. All patients met study criteria: jaw relation and smokers who smoke over 20 cigarettes per day. All subjects were interviewed, and after that orthopantomograms were made. They were used to calculate the degree of alveolar bone loss. The examined subjects were approximately of the same age. Mean age of smokers was 59.9 and nonsmokers 61.8. It was established that differences regarding resorption in men were not significant. The degree of resorption in women smokers and women non-smokers was different, but differences were not significant. It has been proven that the number of cigarettes smoked per day is very important. It is considered that the risk of oral epithelial dysplasia increases when smoking more than 20 cigarettes per day. Considering our results regarding resorption of edentulous alveolar ridge in smokers and nonsmokers, we concluded that there were no significant differences. There are opinions in literature that smoking is not an etiological factor in resorption, but there are some opinions that smoking is connected with the degree of resorption in periodontium. The analyses of resorptive changes in edentuolous smokers were done only around implants and it was estimated that smoking has more influence than other clinical risk factors. On the bases of our research we may conclude that smoking does not directly affect the degree of resorption of edentulous alveolar ridge with complete denture wearers.

An Edenturous Patient with Severe Alveolar Ridge Resorption Who Had Difficulty in Maxillomandibular Residual Relationship: A Case Report

An Edenturous Patient with Severe Alveolar Ridge Resorption Who Had Difficulty in Maxillomandibular Residual Relationship: A Case Report

Ten-year results of a prospective study using porous-surfaced dental implants and a mandibular overdenture.

Numerous investigators have used osseointegrated dental implants as retention for mandibular overdentures, but few have reported 10-year outcomes or incorporated carefully standardized radiographs to document crestal bone loss. The purpose of this study was to use a prospective clinical trial design to assess the performance of short sintered porous-surfaced dental implants with a mandibular complete overdenture when all patients in the trial had undergone 10 years of continuous function. Fifty-two fully edentulous patients, most with advanced alveolar ridge resorption, each received three free-standing Endopore implants (7-10 mm in length, mean length, 8.7 mm; Innova Corporation, Toronto, ON, Canada) in the mandibular symphysis region. After 10 weeks of submerged healing, these implants were used to support an overdenture. Carefully standardized radiographs, using a customized stainless steel filmholder attached to each implant and the x-ray tube, were collected at baseline, 3 months, 6 months, yearly to 5 years, and then again at 7and 10 years. Life table analysis revealed a 10-year implant survival of 92.7% and a mean annual bone loss after year 1 of 0.03 mm. Short free-standing dental implants with a sintered porous surface used for implant fixation are a predictable and effective means of retaining a mandibular overdenture in patients with advanced mandibular ridge resorption.

Degree of the residual alveolar ridge resorption registrated by ortopantomograms among immediate and classic complete denture users

Degree of residual ridge loss is influenced by sistemic phactors, but during the first phase after extraction local phactors are dominant. Patohistological changes of alveolar processus of jaws show the possibility of negative influence of complete dentures on support tissue. In this study, on the chosen sample, the degree of alveolar ridge loss was measured in the group of immediate complete denture users (30 patients) and classical complete denture users ( 30 patients).Height of residual alveolar ridge was measured on ortopantomograms. Localization of referent points proportion was used because of neutralization of shadow distorsion (five in maxilla and five in mandibula). The first ortopantomogram was made at the time of delivering dentures, and the second one six months later. The final measurement of alveolar ridge height is bigger in the group with classical dentures. The reduction degree of residual alveolar ridge is bigger in the group of immediate complete denture users in the first six months.

Reline materials--handle with care? An investigation into the effect of varying the powder/liquid ratio on some properties of auto-polymerising acrylic resin materials.

The fit of the denture base to the alveolar ridge progressively declines with alveolar ridge resorption. Once a denture becomes ill-fitting there are two main treatment options: to construct a new denture or to restore the fit of the existing denture. A denture may be relined as a laboratory procedure or at the chairside in the dental clinic. The chairside reline technique involves the direct application of auto-polymerising acrylic resin materials to the prepared denture base and the material is allowed to polymerise in the patient's mouth. The reline materials are generally supplied as a powder and a liquid. Clinicians and laboratory dental staff do not always follow manufacturers' recommended guidelines and the tendency can be simply to add varying quantities of powder and liquid until the desired consistency is achieved. This method however may have deleterious effects on the properties of the resultant material. The aim of the study was to investigate the effect of varying the powder/liquid ratio on some properties of three auto-polymerising acrylic resin reline materials. The properties investigated were the flow characteristics in terms of the manipulation and setting time and the hardness. Four powder and liquid ratios were chosen. For all the materials studied, a clinically useful lengthening of the manipulation time can be achieved by increasing the amount of liquid added to the powder. However, this is perhaps offset by the fact that it is associated with a corresponding increase in the setting time and resultant increase in clinical chairside time. There were significant differences in surface hardness when the powder/liquid ratio was altered.

Extraction Site Reconstruction for Alveolar Ridge Preservation. Part 2: Membrane-Assisted Surgical Technique

Alveolar ridge resorption has long been considered an unavoidable consequence of tooth extraction. Guided bone regeneration techniques and the use of bone replacement materials have both been shown to enhance socket healing and to potentially modify the resorption process. This article will describe a surgical technique using textured, high-density polytetrafluoroethylene (PTFE) membrane and particulate bone replacement materials for graft containment and prevention of soft tissue ingrowth into healing extraction sites. The technique described does not require primary closure, facilitating the preservation of keratinized mucosa and gingival architecture.

Extraction site reconstruction for alveolar ridge preservation. Part 1: rationale and materials selection.

Alveolar ridge resorption has long been considered an unavoidable consequence of tooth extraction. While the extent and pattern of resorption is variable among individuals, there is a progressive loss of ridge contour as a result of physiologic bone remodeling. Over the long term, prosthodontic complications, loss of function, and inadequate bone for the placement of dental implants may result. Guided bone regeneration techniques and the use of bone replacement materials have both been shown to enhance socket healing and modify the resorption process. This review describes the process of alveolar bone loss, materials for extraction site grafting, and proposed mechanisms for ridge preservation.

Development of a nondestructive compliance test for resilient denture liners.

Resilient denture liners are prescribed for patients who cannot adjust to hard-based dentures because of a thin mucosa or severe alveolar ridge resorption. A nondestructive test to evaluate compliance of new soft liner materials will be useful in clinical trials. The purpose of this study was to evaluate a nondestructive compliance testing technique designed to characterize long-term, silicone-based resilient denture liner materials. Samples of thicknesses of 1.1, 2.2, 3.3, and 4.4 mm of 2 materials (MPDS-SL [Lai Laboratories, Inc, Burnsville, MN] and Molloplast-B [Buffalo Dental, New York, NY]) were assessed for compliance using a closed-loop servohydraulic testing system, applying a 3 lb force following a squarewave pattern; force and position values were recorded using a storage oscilloscope. The oscilloscope values were analyzed using computer software to determine compliance values. The effect of material thickness was examined by testing wedges of the 2 materials. The testing technique used showed that differing thicknesses had significantly different compliance values (p <.0001). In the materials used to evaluate the technique, MPDS-SL behaved more elastically than did Molloplast-B (p <.0001). Material thicknesses beyond 2.2 mm did not increase compliance, although MPDS-SL had a steeper thickness-compliance curve than Molloplast-B. The method used to test compliance proved to be sufficiently sensitive to distinguish between 2 materials and between varying thicknesses. The sensitivity and nondestructive nature of this test show its suitability for clinical evaluation of resilient denture liners.

Endodontic disease of the mandibular first molar tooth secondary to caudal crossbite in a young Shetland sheepdog.

A six month-old intact female Shetland sheepdog was referred to the University of Illinois Veterinary Dental Clinic with a left-sided mandibular deviation and a thickened left ventral mandible in the region of the first molar tooth. On oral examination, left caudal crossbite was diagnosed. Dental radiographs revealed endodontic disease of the mandibular first molar tooth involved in the crossbite. Because of the difficulty of treating caudal crossbite and the potential of a pathological mandibular fracture, the endodontically affected tooth was extracted. Ten months following the extraction, mandibular deviation and alveolar bone lysis were resolved, but alveolar ridge resorption was present. The abnormal occlusal relationship caused by the caudal crossbite may have led to movement of the tooth, resorption of the tooth alveolus, and irreversible pulpal damage. Although not employed in this case, use of alveolar ridge preservation techniques can prevent mandibular bone loss after extractions.

欠損部顎堤診査に対する顎顔面断層Ｘ線撮影装置Ｓｃａｎｏｒａの有用性

A multipurpose, maxillofacial X-ray tomographic device, Scanora 6 (Soledex), which can be installed in dental clinics because of its small size compared to conventional CT, has been developed and introduced to Japan. In a previous study, we examined the basic performance of Scanora to assess its applicability to prosthodontic diagnosis and reported that Scanora permitted evaluation of the maxillofacial morphology and structure including jaw bone and temporomandibular joints, that X-rays obtained with Scanora were highly reproducible, and that it was a very useful instrument for examination of temporomandibular joints.In this study, prosthodontic diagnosis was carried out using Scanora in 5 patients with severe resorption or morphological abnormality of alveolar ridge in the area of defect.It was found relatively easy to derive clear-cut information on alveolar morphology, which is an important element in prosthodontic diagnosis, from tomograms obtained with Scanora.

Gonial angles and condylar and ramus height of the mandible in complete denture wearers--a panoramic radiograph study.

It has been accepted that the shape of the mandibular base, and especially the gonial angle of the mandible, correlates with the function of the jaw closing muscles. The gonial angles of the mandible and condylar and ramus heights of 30 complete denture wearers (18 women, 12 men, mean age 61 years, range 42-74 years) coming for renewal of their dentures were measured using panoramic radiographs. The mean period of edentulousness was 26 years (range 10-53 years). No statistically significant difference was observed between the sexes in the the sizes of gonial angles and condylar and ramus heights. The right gonial angle was statistically significantly smaller than the left one and correlated negatively with the ramus height in both sides but positively with the increased EMG activity in the right masseter muscle. The size of the gonial angle and the condylar and ramus heights did not correlate with the age of the patients, edentulous period or alveolar ridge resorption.

Gonial angles and condylar and ramus height of the mandible in complete denture wearers—a panoramic radiograph study

summary It has been accepted that the shape of the mandibular base, and especially the gonial angle of the mandible, correlates with the function of the jaw closing muscles. The gonial angles of the mandible and condylar and ramus heights of 30 complete denture wearers (18 women, 12 men, mean age 61 years, range 42–74 years) coming for renewal of their dentures were measured using panoramic radiographs. The mean period of edentulousness was 26 years (range 10–53 years). No statistically significant difference was observed between the sexes in the the sizes of gonial angles and condylar and ramus heights. The right gonial angle was statistically significantly smaller than the left one and correlated negatively with the ramus height in both sides but positively with the increased EMG activity in the right masseter muscle. The size of the gonial angle and the condylar and ramus heights did not correlate with the age of the patients, edentulous period or alveolar ridge resorption.

Relationship between size of denture foundation area and resorption of alveolar ridge in the edentulous mandible

summary The relationship between the size of the denture foundation area and the resorption of the alveolar ridge was investigated in 55 edentulous subjects. The denture foundation area was recorded using a modelling compound impression technique with border moulding. Both sides of each edentulous mandible were examined separately, making a total of 110 experimental sides in the study. On a stone cast made from each impression, the size of the superficial denture foundation area and of the projected denture foundation area on the tentative plane of occlusion of each anatomical zone were measured. The vertical height of the alveolar ridge at the lateral incisor and first molar region was also evaluated. The size of the superficial denture foundation area in the antero‐lingual and postero‐lingual zones showed no significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the anterior section showed negative significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the posterior section showed no significant correlation with the degree of alveolar ridge resorption.

Relationship between size of denture foundation area and resorption of alveolar ridge in the edentulous mandible.

The relationship between the size of the denture foundation area and the resorption of the alveolar ridge was investigated in 55 edentulous subjects. The denture foundation area was recorded using a modelling compound impression technique with border moulding. Both sides of each edentulous mandible were examined separately, making a total of 110 experimental sides in the study. On a stone cast made from each impression, the size of of the superficial denture foundation area and of the projected denture foundation area on the tentative plane of occlusion of each anatomical zone were measured. The vertical height of the alveolar ridge at the lateral incisor and first molar region was also evaluated. The size of the superficial denture foundation area in the antero-lingual and postero-lingual zones showed no significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the anterior section showed negative significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the posterior section showed no significant correlation with the degree of alveolar ridge resorption.

The Benefits of Estrogen Replacement Therapy on Oral Health

Background: Several studies have demonstrated a relationship between tooth loss and alveolar residual ridge resorption and systemic osteoporosis. The recognized benefit of estrogen replacement therapy (ERT) in postmenopausal osteoporosis prompted review of the Leisure World Cohort Study regarding the effects of ERT on tooth loss and the need for dentures in older women. Methods: The Leisure World Cohort, established in 1981, comprises 13 979 residents (8877 women) of a retirement community. Of the 5935 cohort women alive in 1992, 3921 returned a dental survey with sufficient information to analyze relationships with ERT as reported on the original baseline questionnaire. Results: After adjusting for age, tooth loss and rates of edentia were significantly lower in estrogen users than in nonusers (relative risk for edentia, 0.64; 95% confidence interval, 0.51 to 0.79). The proportion of women with edentia decreased with increasing duration of ERT. Denture wearing was also less common in estrogen users than in nonusers (relative risk, 0.81; 95% confidence interval, 0.71 to 0.93) and decreased with increasing duration of ERT. Conclusion: Estrogen replacement therapy may be beneficial in preventing tooth loss and the need for dentures in older women. (Arch Intern Med. 1995;155:2325-2329)

The Benefits of Estrogen Replacement Therapy on Oral Health

Several studies have demonstrated a relationship between tooth loss and alveolar residual ridge resorption and systemic osteoporosis. The recognized benefit of estrogen replacement therapy (ERT) in postmenopausal osteoporosis prompted review of the Leisure World Cohort Study regarding the effects of ERT on tooth loss and the need for dentures in older women. The Leisure World Cohort, established in 1981, comprises 13,979 residents (8877 women) of a retirement community. Of the 5935 cohort women alive in 1992, 3921 returned a dental survey with sufficient information to analyze relationships with ERT as reported on the original baseline questionnaire. After adjusting for age, tooth loss and rates of edentia were significantly lower in estrogen users than in nonusers (relative risk for edentia, 0.64; 95% confidence interval, 0.51 to 0.79). The proportion of women with edentia decreased with increasing duration of ERT. Denture wearing was also less common in estrogen users than in nonusers (relative risk, 0.81; 95% confidence interval, 0.71 to 0.93) and decreased with increasing duration of ERT. Estrogen replacement therapy may be beneficial in preventing tooth loss and the need for dentures in older women.