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PubMed2005

The effect of maximum bite force on marginal bone loss in mandibular overdenture treatment: an in vivo study.

The impact of bite force on the marginal bone response around implants is a subject of debate. This study focused on the effect of maximum bite force on marginal bone levels in mandibular implant overdenture treatment. In addition, the effect of the sequence of 3 different loading conditions on marginal bone loss was evaluated in vivo. The patient population consisted of a group of 18 patients. They received 2 implants in the mandible and a new denture without attachments during the period of submerged implant healing. After second stage surgery, the denture was provided with a ball, magnet or bar-clip attachment. There was a transition of attachment type after 3 and 6 months of function. The sequence in which the attachments were used was randomised. Radiographic marginal bone loss was measured after the period of submerged implant healing and after 3, 6 and 9 months of functional implant loading. Maximum bite force measurements were obtained just prior to second stage surgery with the new denture without attachment. Bite force measurements were also obtained after 3, 6 and 9 months of loading with the implant-retained overdenture. The latter 3 values were averaged. The mean bone loss during the period of submerged healing and during functional loading was 1.7 mm (0.7 mm) and 1.3 mm (0.6 mm), respectively. A relationship between maximum bite force during the period of submerged healing or during the period of functional loading on the one hand and the amount of marginal bone loss on the other could not be demonstrated. The sequence in which the different attachment types were used did not influence the observed amount of marginal bone loss.

Adolescent↗
PubMed2002

Bone reactions at implants subjected to experimental peri-implantitis and static load. A study in the dog.

AIM: The aim of the present experiment was to study peri-implant tissue reactions to lateral static load at implants subjected to experimental mucositis or peri-implantitis. MATERIAL AND METHODS: 5 beagle dogs were used. The mandibular premolars were extracted. After 12 weeks, 3 implants were installed in each quadrant of the mandible. In one side, the implants were designed with a SLA surface and in the contralateral side with a turned surface. A plaque control program was initiated. 12 weeks later, the central and posterior implants were connected with an appliance containing an expansion screw. Cotton ligatures were placed around the neck of the anterior and posterior implants in both sides, and the plaque control measures were terminated. Sixteen weeks later the ligatures were removed. After 8 weeks without ligatures, the expansion screws in both sides were activated. Once every 2 week during a 12-week interval, the screws were reactivated. Thus, the model included 3 different experimental sites of each surface group: group M+L (mucositis+load); group P (peri-implantitis); group P+L (peri-implantitis+load). Fluorochrome labels were injected and standardized radiographs obtained. The animals were sacrificed and block biopsies of all implant sites dissected and prepared for histological analysis. RESULTS: It was demonstrated that the lateral static load failed to induce peri-implant bone loss at implants with mucositis and failed to enhance the bone loss at implants with experimental peri-implantitis. The proportion of bone labels and the bone density in the interface zone were significantly higher in group P+L than in group P. CONCLUSION: It is suggested that a lateral static load with controlled forces may not be detrimental to implants exhibiting mucositis or peri-implantitis.

Alveolar Bone Loss↗
PubMed2005

Bone reactions to longstanding functional load at implants: an experimental study in dogs.

OBJECTIVES: The aims of the present investigation were (i) to study marginal bone level alterations following implant installation, abutment connection and functional loading and (ii) to analyse bone tissue reactions to functional load. MATERIAL AND METHODS: Six beagle dogs, about 1-year old, were used. All mandibular pre-molars were extracted. Three months later four implants of the Astra Tech Implants Dental System were installed in one side of the mandible and four standard fixtures of the Brånemark System were placed in the contralateral side of the mandible. Abutment connection was performed 3 months later and a plaque control programme was initiated. Three months after abutment connection fixed partial dentures (FPDs) made in gold were cemented to the maxillary canines and pre-molars. FPDs were also connected to the three posterior implants in each side of the mandible, while the mesial implant in each side was used as an unloaded control. Radiographs were obtained from all implant sites following implant installation, abutment connection and FPD placement. Ten months after the FPD placement the radiographic examination was repeated. The animals were sacrificed and biopsies from all implant sites were obtained and prepared for histological analysis. RESULTS: The radiographic analysis revealed that largest amount of bone loss occurred following implant installation and abutment connection and that this loss was more pronounced at Brånemark than at Astra implants. The bone level alterations that were observed at implants exposed to 10 months of functional load in both implant systems were small and did not differ from control sites. The histological analysis revealed that implants exposed to functional load exhibited a higher degree of bone-to-implant contact than control implants in both implant systems. CONCLUSION: It is suggested that functional load at implants may enhance osseointegration and does not result in marginal bone loss.

Alveolar Bone Loss↗
PubMed1998

The mucosal attachment at different abutments. An experimental study in dogs.

The present experiment was performed to examine if the material used in the abutment part of an implant system influenced the quality of the mucosal barrier that formed following implant installation. 5 beagle dogs were included in the study. The mandibular premolars and the 1st, 2nd and 3rd maxillary premolars were extracted. Three fixtures of the Brånemark System were installed in each mandibular quadrant (a total of 6 fixtures per animal). Abutment connection was performed after 3 months of healing. In each dog the following types of abutments were used: 2 "control abutments" (c.p. titanium), 2 "ceramic abutments" (highly sintered Al2O3), 1 "gold abutment", and 1 "short titanium abutment". This "short titanium abutment" was provided with an outer structure made of dental porcelain fused to gold. Following abutment connection a plaque control program was initiated and maintained for 6 months. The animals were sacrificed and perfused with a fixative. The mandibles were removed and each implant region was dissected, demineralized in EDTA and embedded in EPON. Semithin sections representing the mesial, distal, buccal and lingual aspects of the peri-implant tissues were produced and subjected to histological examination. The findings from the analysis demonstrated that the material used in the abutment portion of the implant influenced the location and the quality of the attachment that occurred between the periimplant mucosa and the implant. Abutments made of c.p. titanium or ceramic allowed the formation of a mucosal attachment which included one epithelial and one connective tissue portion that were about 2 mm and 1-1.5 mm high, respectively. At sites where abutments made of gold alloy or dental porcelain were used, no proper attachment formed at the abutment level, but the soft tissue margin receded and bone resorption occurred. The abutment fixture junction was hereby occasionally exposed and the mucosal barrier became established to the fixture portion of the implant. It was suggested that the observed differences were the result of varying adhesive properties of the materials studied or by variations in their resistance to corrosion.

Aluminum Oxide↗
PubMed1985

Use of intraoral prostheses in external beam radiation of oral and perioral cancer.

An intraoral prosthesis can be used to position and immobilize tissues in beam-directed radiation therapy for cancer. The prosthesis stabilizes oral structures within the treatment field to permit improve control of field size and thus spare tissues that do not require treatment. The use of an oral prosthesis diminishes both early and late complications of radiation treatment. The prostheses can be used to advantage in conjunction with free-hand and precision methods for the orientation of patients.

Aged↗
PubMed2003

[Analysis of patient's satisfaction with the mandibular implant-borne overdentures].

OBJECTIVE: To compare the subjective attitudes of fully edentulous patients in mandible toward the implant-borne overdentures and toward the previous complete dentures. METHODS: 16 fully edentulous patients in mandible were consecutively included in this study and the attitudes toward the implant-borne overdentures and the previous complete dentures were surveyed through questionnaires at the first visit and after the implant prosthesis. RESULTS: There exists significant difference regarding to the comfort, function and fixedness between implant-borne overdentures and the previous complete denture. CONCLUSION: It was revealed that mandibular bar-clip retention implant-borne overdentures can highly fulfill patient's demands.

Aged↗
PubMed2004

Bone regeneration by bodily tooth movement: dental computed tomography examination of a patient.

A 32-year-old man was examined with computed tomography before and after orthodontic treatment, and alveolar bone levels at the edentulous spaces were assessed. When the computed tomography scans were compared, 2.2 to 5.2 mm of additional craniocaudal alveolar bone remodeling by bodily tooth movement was found in the space-opening region. Bodily movement was achieved with single- and crossed-lever-arm mechanics. Root resorption measuring 1 to 4 mm was observed at the mandibular anterior region, where teeth were used for anchorage to upright the molars.

Adult↗
PubMed2005

Treatment of epiphyseo-metaphyseal fractures in children with an original implant. The threaded pin with an adjustable lock (Fixano).

OBJECTIVE: Improvement of stability of internal fixation of epiphyseo-metaphyseal fractures in children with an implant characterized by its small diameter, easy utilization and its versatility. It avoids the drawbacks of screw fixation particularly in respect to the growth plate. INDICATIONS: Potentially all epiphyseo-metaphyseal fractures in children. CONTRAINDICATIONS: None. Crossing of the growth cartilage by small pins (< 2 mm) is without consequences under the condition that no compression is applied and that correction of a faulty pin position is limited to one. SURGICAL TECHNIQUE: In general, two threaded pins are used. They are inserted in a divergent fashion after the fracture has been reduced. Percutaneous insertion is possible. An adjustable lock screwed on a special key is slid over the end of the pin and put in contact with bone. It is squeezed until the key breaks off. The pins are then shortened. RESULTS: Since November 1999 these pins have been used for six olecranon fractures. In January 2002 we extended the indication to other fracture sites. Between January 2002 and July 2003 this system has been used 37 times (six olecranon fractures, eleven lateral condylar fractures and 13 medial epicondylar fractures of the elbow, and seven fractures of the ankle). A total of 43 fractures were treated (20 girls, 23 boys, average age 9.8 +/- 3.6 years) Average duration of follow-up 16.8 +/- 4.7 months. The assessment of results was based on technical, radiographic, and functional aspects. The overall results were good, in particular in respect to the stability of implants and the functional results. No secondary displacement, nor nonunion were observed; the pins were removed in all children at 6 weeks. The ease of handling the implants and the good clinical and radiologic results led us to propose these pins for routine use in epiphyseal and epiphyseo-metaphyseal fractures in children. Some improvements, however, are indicated principally, in particular in respect to the control of compression achieved by the adjustable lock.

Bone Nails↗
PubMed2004

Bone healing after the inferior alveolar nerve lateralization: a histologic study in rabbits (Oryctolagus cuniculus).

PURPOSE: The purpose of this article is to evaluate the bone healing around 2 different dental implant surfaces after the lateralization surgery of the inferior alveolar nerve (IAN) during an 8-week healing period in rabbits, and to check if there is any interaction between the implants and the nerve. MATERIALS AND METHODS: The IAN lateralization was performed in an experimental rabbit model. Eight adult female rabbits (Oryctolagus cuniculus) underwent the surgical procedure, and 1 implant was placed on each side of the mandible while the nerve was lateralized. On both sides, the nerve was repositioned directly in contact with the implant surface. With the intention of obtaining comparative results, smooth titanium implants were installed on the right side, and blasted Al2O3 ones were placed on the left. During the healing period, bone tracers were administered subcutaneously to check different periods of bone ingrowth. RESULTS: Histologic section, regardless of the studied surface, showed bone remodeling around the nerve, without contact between the nerve and the implanted surface. The bone blocks containing implants were histomorphometrically examined through computerized analysis, and the results obtained showed that the bone remodeling around the nerve occurred during the first weeks of healing. Through analysis of variance, the blasted Al2O3 implants showed at least 2.5-fold greater bone neoformation compared with the smooth titanium implants. CONCLUSIONS: Our results showed that there was no significant difference in the healing process concerning the nerve between the 2 studied surfaces. No interaction was detected between the nerve and the implants.

Air Abrasion, Dental↗
PubMed1998

Short-term implantation effects of a DCPD-based calcium phosphate cement.

Calcium phosphate cements can be handled in paste form and set in a wet medium after precipitation of calcium phosphate crystals in the implantation site. Depending on the products entering into the chemical reaction leading to the precipitation of calcium phosphates, different phases can be obtained with different mechanical properties, setting times and injectability. We tested a cement composed of a powder, containing beta-tricalcium phosphate (beta-TCP) and sodium pyrophosphate mixed with a solution of phosphoric and sulphuric acids. The cement set under a dicalcium phosphate dihydrate (DCPD)-based matrix containing beta-TCP particles. This was injected with a syringe into a defect drilled in rabbit condyles, the control being an identical defect left empty in the opposite condyle. The condyles were analysed histologically 2, 6 and 18 weeks after implantation. After injection into the bone defect the cement set and formed a porous calcium phosphate structure. Two different calcium phosphate phases with different solubility rates could be identified by scanning electron microscopy (SEM) observation. The less-soluble fragments could be degraded by cell phagocytosis in cell compartments of low pH or integrated in the newly formed bone matrix. The degradation rate of the material was relatively high but compatible with the ingrowth of bone trabeculae within the resorbing material. The ossification process was different from the creeping substitution occurring at the ceramic contact. Bone did not form directly at the cement surface following the differentiation of osteoblasts at the material surface. The trabeculae came to the material surface from the edges of the implantation site. Bone formation in the implantation site was significantly higher than in the control region during the first week of implantation. In conclusion, this material set in situ was well tolerated, inducing a mild foreign-body reaction, which did not impair its replacement by newly formed bone within a few weeks.

Animals↗
PubMed2004

The expanding role of dental oncology in head and neck surgery.

A comprehensive dental oncologic screening should be part of the pretreatment workup of patients who have head and neck cancer. This screening should be performed by a dentist who is familiar with the pathologic process of disease and type of treatment being rendered; in addition, he or she should comprehend the various morbidities associated with eradicating head and neck malignancy. The dental oncologist must provide the timeline for the surgeon and radiation oncologist in which all necessary dental treatment will be completed. It is important at this juncture to educate the patient as to the possible short- and long-term complications,no matter what treatment course they choose.Osseointegrated implants used in the rehabilitation of patients who have undergone head and neck surgery have provided a more reliable means of retaining intraoral and extraoral prostheses. With close communication between the head and neck surgeon and dental oncologist, and careful patient selection, better functional outcomes may be provided.

Dental Prosthesis↗
PubMed2000

Expanded polytetrafluoroethylene entubulation of the rabbit inferior alveolar nerve.

OBJECTIVE: The purpose of this study was to evaluate the use of an expanded polytetrafluoroethylene conduit in the treatment of a 6. 0-mm gap in the rabbit inferior alveolar nerve and compare the results with those of an autogenous interpositional tibial nerve graft. STUDY DESIGN: The inferior alveolar nerves of 5 adult New Zealand White female rabbits (10 nerves) were exposed bilaterally, and a 6-mm segment of each nerve was resected. On one side, chosen at random, the gap was immediately bridged through use of an 8.0 x 2. 0-mm expanded polytetrafluoroethylene conduit; on the other side, the gap was grafted with an autogenous tibial nerve graft. Two randomly selected nerves served as sham-dissected controls. At 15 weeks after surgery, the animals were killed and the entire nerve segments were harvested and prepared according to standard fixation and embedding techniques. The sections were examined histomorphometrically to quantify the degree of axonal regeneration through definition of fascicular number, total fascicular surface area, axonal density, and mean axonal diameter at 3 locations along the repair site. RESULTS: Light microscopic examination revealed the presence of disorganized neural tissue in both groups, with slightly more fibrovascular interfascicular tissue in the expanded polytetrafluoroethylene group. Histomorphometric analysis revealed no significant differences between groups for most of the measured variables. The mean axonal diameter varied between groups, and the fascicular number was greater in the expanded polytetrafluoroethylene group at the middle site. CONCLUSIONS: This study demonstrates that regeneration of the inferior alveolar nerve can occur across a 6.0-mm gap through an expanded polytetrafluoroethylene tube with results comparable to those of an autogenous nerve graft, significant donor site morbidity being avoided. The significant differences between groups were probably due to greater containment of regenerating axonal fibers in the expanded polytetrafluoroethylene group.

Animals↗
PubMed2006

Treatment planning of the edentulous mandible.

Edentulism can be a debilitating handicap. Zarb described endentulous individuals who could not function as 'denture cripples'.(1) Most difficulty with complete denture prostheses arises from the inability to function with the mandibular prostheses. Factors that adversely affect successful use of a complete denture on the mandible include: 1) the mobility of the floor of the mouth, 2) thin mucosa lining the alveolar ridge, 3) reduced support area and 4) the motion of the mandible (Figs 1,2). These factors alone can explain the difficulty of wearing a denture on the mandibular arch compared to the maxillary arch. The maxilla exhibits much less mobility on the borders of the denture than the mandible, moreover having a stable palate with thick fibrous tissues available to support the prostheses and resist occlusal forces. These differences explain most of the reasons why patients experience difficulty with using a complete denture on the mandibular arch compared to the maxillary arch.

Dental Prosthesis, Implant-Supported↗
PubMed2006

Feasibility and influence of the microgap of two implants placed in a non-submerged procedure: a five-year follow-up clinical trial.

BACKGROUND: The aim of this study was to evaluate the feasibility of using a two-piece implant system in a non-submerged procedure and to study the impact of the microgap between the implant and abutment. METHODS: Sixty edentulous patients (Cawood Class V-VI) participated in this study. After randomization, 20 patients received two two-piece implants placed in a non-submerged procedure, 20 patients received two two-piece implants placed in the traditional submerged procedure, and 20 patients were treated with two one-piece dental implants placed in the traditional non-submerged procedure. The implants were placed in the mandible for overdenture treatment. A standardized clinical evaluation was performed and radiographs were taken immediately after denture insertion and yearly up to 5 years. Peri-implant samples were collected 12, 36, and 60 months after loading with sterile paper points and analyzed for the presence of putative periodontal pathogens using culture techniques. RESULTS: One two-piece implant of the non-submerged group and one two-piece implant of the submerged group were lost after 6 and 12 months, respectively. After 5 years of functioning, no significant clinical, radiological, or microbiological differences were found between the three groups. No association was found between the level of the microgap and the amount of bone loss. CONCLUSIONS: The results of this study indicate that dental implants designed for a submerged implantation procedure can also be used in a non-submerged procedure and may be as predictable as when used in a submerged procedure or as one-piece implants. The microgap at the crestal level in two-piece implants does not appear to have an adverse effect on the amount of peri-implant bone loss.

Alveolar Bone Loss↗
PubMed1999

Chin surgery: I. Augmentation--the allures and the alerts.

The correction of sagittal deformities of the chin presents a seemingly simple surgical challenge. However, several authors have reported negative sequelae from such chin surgery, During the past 11 years, the senior author (B.M.Z.) has evaluated more than 100 such cases of adverse results after chin augmentation. Many surgeons, it seems, use chin implants unnecessarily and, thus, get into trouble. Because alloplastic chin augmentation is deceptively easy, it tends to be overused in certain situations. Either the surgeon's evaluation is too narrowly focused or his/her abilities to perform other types of surgery (e.g., osseous genioplasty) are limited. Herein, the authors present a diagnostic evaluation protocol, QUAC (Quick Analysis of the Chin), to assist in avoiding simple mistakes in alloplastic chin augmentation. This protocol will alert the surgeon to situations that, if unrecognized, will cause problems and create an unhappy patient. This article will specifically focus on (1) lower lip analysis; (2) the effect of the labiomental fold; (3) chin pad evaluation, both static and dynamic; (4) the anatomy of the cleft chin; (5) special situations; and (6) how to troubleshoot three common problems. The accompanying article, Chin Surgery II, will present a new operation that treats a chin problem that was previously difficult to correct.

Adult↗
PubMedDate not supplied

Implant reconstruction of a surgical defect.

This article describes grafting of the surgical defect created from the treatment of a mandibular ameloblastoma. Current prosthetic techniques are used and demonstrated during the implant-supported reconstruction of the deformity.

Adult↗