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Biomedical subjects

M Chiapasco

Publications and source records attributed to M Chiapasco.

At least 19 recordsLinked to original sources
PubMed2002

Long-term clinical effectiveness of oral implants in the treatment of partial edentulism. Seven-year life table analysis of a prospective study with ITI dental implants system used for single-tooth restorations.

One hundred and eight-seven ITI implants were prospectively followed from November 1992 to July 2000, in order to evaluate the clinical efficiency and the long-term prognosis in 109 partially edentulous patients (69 women and 40 men; average age 41.3 years). Of these 187 implants, 69.5% were placed in the mandible and 30.5% in the maxilla. After a healing period that ranged from three to six months, the osseointegrated implants (n = 184) were restored with single crowns. Three implants were extracted prior to loading the fixture and were considered early failures. Each implant was reassessed on a yearly basis, both clinically and radiographically. The results of the investigation, which were evaluated according to predefined success criteria, were reviewed in accordance with a life table method. During the follow-up, six cases were deemed to be late failures. In each of these cases, a suppurative infection of the peri-implant tissue was diagnosed: in one implant, the infection could not be eradicated and the implant was removed. When 11 drop-outs were included in the analysis, the cumulative survival and success rates for the whole sample group were 96.77% and 93.6%, respectively. When only prosthetically loaded implants were considered, the results increased to 99.35% for the cumulative survival rate and 96.18% for the cumulative success rate. The analysis on disaggregated data showed better results for maxillary restorations (survival rate 100%) in comparison to mandible restorations (survival rate 95.11%). It was concluded that, under standard anatomic conditions (bone site height > 8 mm, thickness > 6 mm), prosthetic restoration of partially edentulous patients with the ITI system can be described as a reliable and efficient therapy in the long term.

Adult↗
PubMed2000

Behavior of implants in bone grafts or free flaps after tumor resection.

The authors compared bone resorption of autogenous bone grafts and revascularized free flaps used for the reconstruction of mandibular continuity defects following resection for tumors, before and after the placement of endosseous implants. Ten patients (group 1) were treated with autogenous bone grafts taken from the fibula or the anterior iliac crest; 8 patients (group 2) were treated with iliac or fibula revascularized flaps. Four to 8 months later, 72 endosseous implants were placed in the reconstructed areas. After a further healing period of 4-6 months, patients were rehabilitated with implant-borne prostheses. The following parameters were evaluated and compared between the two groups: 1) bone resorption of grafts and free flaps before and after implant placement; 2) peri-implant bone resorption mesial and distal to each implant, immediately after prosthetic rehabilitation and then during yearly follow-ups. Bone resorption before implant placement showed mean values of 3.53 mm in group 1, and 0.96 mm in group 2. Peri-implant bone resorption was: 0.49 mm (39 implants) in group 1, and 0.45 mm (30 implants) in group 2, at time of prosthetic rehabilitation; 0.78 mm (39 implants) in group 1, and 0.89 mm (30 implants) in group 2, 12 months after prosthetic load; 1.16 mm (24 implants) in group 1, and 1.02 mm (13 implants) in group 2, 24 months after the prosthetic load. A significant difference in bone resorption before implant placement was found between the two groups, whereas it was not found after implant placement and prosthetic load. The failure rate according to Albrektsson criteria was 4.9% (2/41 implants) in group 1, and was 3.2% (1/31) in group 2.

Adult↗
PubMed2000

Spontaneous bone regeneration after enucleation of large mandibular cysts: a radiographic computed analysis of 27 consecutive cases.

PURPOSE: This study evaluated the spontaneous bone healing after enucleation of large mandibular cysts subjectively and with a computed analysis of postoperative panoramic radiographs. PATIENTS AND METHODS: Twenty-nine patients had large mandibular cysts treated by surgical enucleation. Postoperative clinical and radiographic examinations were performed at 6, 12, and 24 months in 27 patients. Bone regeneration and reduction of the residual cavities and bone density were evaluated with a computed analysis of preoperative and postoperative panoramic radiographs. A subjective and clinical radiographic evaluation of the healing process also was performed. RESULTS: Uneventful healing and spontaneous filling of the residual cavities was obtained in all cases. The computed analysis of the postoperative radiographs showed mean values of reduction in size of the residual cavity of 12.34% after 6 months, 43.46% after 12 months, and 81.30% after 24 months. The increase in bone density was 37% after 6 months, 48.27% after 12 months, and 91.01% after 24 months. CONCLUSION: Spontaneous bone regeneration can occur in large mandibular cysts without the aid of any filling materials. This simplifies the surgical procedure, decreases the economic and biologic costs, and reduces the risk of postoperative complications.

Adolescent↗
PubMed1999

Clinical outcome of autogenous bone blocks or guided bone regeneration with e-PTFE membranes for the reconstruction of narrow edentulous ridges.

The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation: guided bone regeneration with e-PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e-PTFE membranes. Thirty partially edentulous patients, presenting insufficient bone width (less than 4 mm) in the edentulous sites for installation of screw-type titanium implants, were selected and assigned to two different treatment modalities. Fifteen patients (group 1) were treated by means of guided bone regeneration with e-PTFE membranes supported by stainless steel screws and autologous bone chips taken from intraoral sites. Fifteen patients (group 2) were treated by means of autologous bone blocks taken from intraoral or extraoral sites (anterior iliac crest and calvaria) and stabilized with titanium microscrews. Six to 8 months later, during re-entry for implant insertion, the gain of ridge width obtained was measured. In group 1 the average amount of bone gain was 2.7 mm, whereas in group 2 the value was 4.0 mm. Five to 6 months after implant placement prosthetic rehabilitation was started. The mean follow-up after prosthetic load has been 22.4 months. Success rates of implants according to Albrektsson criteria has been 93.3% in group 1, and 90.9% in group 2. Although a statistical comparison between the two treatment modalities may not be feasible, due to the bias resulting from the choice of treatment by the clinician and from the differences in donor sites and defect extension, some considerations can be made: 1) both methods are a reliable means for the correction of narrow edentulous ridges; 2) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one; 3) the use of semipermeable barriers increases the costs of the surgical procedure, as compared to bone grafting without membranes; 4) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure. Therefore, in case of wide edentulous areas, reconstruction of narrow ridges should be performed with bone blocks without membranes.

Adult↗
PubMed1998

Simultaneous rhinoplasty and maxillomandibular osteotomies: Indications and contraindications.

Functional and esthetic correction of a dentofacial deformity may require not only maxillary or mandibular osteotomies but also a rhinoplasty. Rigid internal fixation makes it possible to perform rhinoplasty and maxillary osteotomies simultaneously. Nevertheless, to plan rhinoplasty correctly it is of paramount importance to predict changes of the nose that will follow osteotomy of the maxilla. The authors present their experience concerning the surgical technique, advantages, and disadvantages of rhinoplasty in combination with orthognathic surgery.

Adult↗
PubMed1997

Modified intraoral maxillo-malar osteotomy: long-term results in 16 consecutive cases.

The authors report their experience with sixteen consecutive cases of maxillo-malar osteotomy via an intraoral approach. Some technical expedients and modifications to the original technique are described here. This procedure was associated in all cases with bilateral sagittal splitting of the mandible and in two cases with vertical reduction of the chin. Results from this series confirm the reliability of this technique and the stability of functional and aesthetic results.

Adult↗
PubMed1997

Implant-retained mandibular overdentures with immediate loading. A retrospective multicenter study on 226 consecutive cases.

A multicenter retrospective study has been conducted on 226 patients necessitating an implant-supported overdenture in the lower jaw. The patients were provided with 904 osseointegrated implants inserted in the interforaminal area of the mental symphisis (4 implants per patient). 4 titanium implant systems were used: TPS and ITI screw implants (Straumann Institute, Waldenburg, Switzerland); Ha-Ti screw implants (Mathys Dental Implants, Bettlach, Switzerland); NLS screw implants (Friatec, Mannheim, Germany). Immediately after implant placement, a U-shaped gold bar was fabricated and implants were immediately loaded with an implant-retained overdenture. Out of 226 patients treated, 194 were followed from a minimum of 2 years to a maximum of 13 years, with a mean follow-up of 6.4 years, whereas 32 patients dropped out during follow-up. The overall failure rate of implants was 3.1% (24/776 implants), whereas the failure rate of bars was 1.5% (3/194 bars). Results from this study showed that the success rate of immediately loaded implants is similar to that obtained in the case of delayed loading, after osseointegration has taken place. In contrast, this method shortens dental rehabilitation times with relevant satisfaction for patients.

Adult↗
PubMed1996

[Surgery of lower third molars and lesions of the lingual nerve].

OBJECTIVE: The authors describe a technical expedient applied during the removal of totally or partially impacted lower third molars, in order to prevent lingual nerve damage. EXPERIMENTAL ASSAY: Retrospective study. MATERIALS AND METHODS: The sample includes 1835 extractions of totally or partially impacted lower third molars, performed on 1030 patients, 493 males and 537 females, aging between 12 and 72 years. All the operations were carried out under local anaesthesia with standardization of the surgical protocol. A mucoperiosteal paramarginal flap was used in case of germectomy, whereas a mucoperiosteal marginal flap with mesial releasing incision was used in case of fully mature teeth. Ostectomy and tooth sectioning were performed using a round and fissure bur respectively, assembled on a straight low-speed handpiece and under irrigation with sterile saline. RESULTS: The authors reported only one case of transient lingual nerve paresthesia (0.05%) which occurred in a 19-years old female presenting a totally impacted third molar mesial-lingual inclination. Symptoms disappeared spontaneously one week postoperatively. Therefore the overall incidence of permanent nerve damage was equal to 0%. CONCLUSIONS: The data reported in literature show a lingual nerve lesion incidence ranging between 0% and 22%. With this simple surgical expedient the incidence of permanent lingual damage was 0%. Thus, it is the authors' opinion that this simple expedient should be applied in all cases of impacted third molar removal.

Adolescent↗
PubMed1996

[Warthin tumor of the palate: an unusual location].

UNLABELLED: Warthin's tumor (papillary cystadenoma lymphomatosum) primarily involves the parotid gland, whereas localization in the palate has been reported by a few authors. A new case of true Warthin's tumor arising from the hard palate is here presented and histogenesis and differential diagnosis are briefly discussed. CASE REPORT: A 50 year-old woman who was referred to us because of the presence of multiple contiguous bluish cyst-like lesions involving both sides of the hard palate mucosa. The lesion was removed with a wide excision involving almost all the soft tissues of the hard palate. Histologic diagnosis (E.E stain) was: papillary cystadenoma lymphomatosum. DISCUSSION AND CONCLUSION: The histogenesis of Warthin's tumor is still controversial. The most widely accepted theory is that the tumor represents a neoplastic proliferation of salivary gland ducts entrapped in pre-existing lymph nodes. In fact, immunohistochemical analysis and cell-surface markers studies have shown that the lymphoid component is predominantly formed by T-lymphocytes, with a relatively small number of polyclonal B-lymphocytes. On the contrary, other authors found opposite relationship between T and B lymphocytes. These findings supported the concept that lymphoid tissue in Warthin's tumor represented a reactive cellular infiltrate in a pattern similar to that seen in reactive lymph nodes. Similar results have been found in this report; moreover, the hard palate does not usually contain lymphatic tissue. This could support the idea that the lymphoid tissue associated with this case is reactive and a direct origin from the ductal epithelium with secondary lymphocytic infiltration is more likely to occur in this area.

Adenolymphoma↗
PubMed1995

Germectomy or delayed removal of mandibular impacted third molars: the relationship between age and incidence of complications.

PURPOSE: To analyze and compare complications and side effects after removal of 1,500 mandibular impacted third molar teeth in three age groups. MATERIALS AND METHODS: The sample comprised 868 patients, 462 women and girls and 406 men and boys aged 9 to 67 years. The patients were divided according to age into the following three groups: group A, aged 9 to 16 years; group B, aged 17 to 24 years; group C, older than 24 years of age. RESULTS: The incidence of complications and side effects was 2.6% in group A, 2.8% in group B, and 7.4% in group C. All complications were temporary except in one instance of mandibular nerve paresthesia that occurred in a group C patient, in whom symptoms were still present 25 months after surgery. CONCLUSION: This study showed no significant difference in the complication rate between groups A and B, but complications significantly increased in group C.

Adolescent↗
PubMed1995

Endosseous implants for prosthetic rehabilitation in bone grafted alveolar clefts.

The authors report their experience in the surgical and prosthetic rehabilitation of three patients affected by sequelae of cleft lip and palate, with residual alveolar cleft and absence of maxillary anterior teeth. The patients were treated by means of late secondary bone grafting of the alveolar cleft, followed by the insertion of endosseous titanium plasma-sprayed implants (IMZ). After a further healing period (6-12 months) fixed dental prostheses were constructed. Preliminary results from this series have shown how dental prostheses supported by endosseous implants in grafted alveolar clefts are a very reliable possibility in dental rehabilitation of this malformation.

Adolescent↗
PubMed1994

[The extraction of the lower third molars: germectomy or late avulsion?].

INTRODUCTION: Lower third molars show the highest incidence of impaction and have been held responsible for pathologies such as pericoronitis, periodontitis, second molars tooth-crown resorption, pain, cysts or odontogenic tumors, primary or secondary crowding of the dentition. Early removal of these teeth to prevent the overmentioned problems is widely acknowledged, as many studies demonstrated a direct correlation between age and incidence of complications. These studies mostly refer to adult patients, while studies about germectomies are few. Because recent contributions showed that the risk of development of these pathologies in presence of impacted third molars is quite low while a certain morbidity associated to this procedure may be expected, a very careful risk to benefit ratio must be considered. The purpose of this study was therefore to compare the incidence of complications and side effects in three age groups, in order to obtain some informations about the choice of the best moment for operation. MATERIALS AND METHODS: The patients, 462 females and 406 males, were divided, according to age, in the following three groups: group A included patients from 9 to 16 years; group B included patients from 17 to 24 years; group C included patients over 24 years. All patients were treated under local anesthesia; surgical procedure and instruments were standardized. RESULTS: In group A, formed by 500 germectomies, the incidence of complications was 2.6% (10 instances of secondary infections, 2 instances of trismus, 1 instance of excessive postoperative bleeding). Group B included 570 procedures and the incidence of complications was 2.8% (3 instances of alveolar osteitis, 7 instances of secondary infections, 2 instances of excessive postoperative bleeding, 2 instances od second molar lesions, 1 instance of inferior alveolar nerve paresthesia, 1 instance of trismus). Group C included 430 procedures and the incidence of complications was 7.4% (2 instances of second molar lesions, 9 instances of alveolar osteitis, 8 instances of secondary infections, 4 instances of excessive postoperative bleeding, 6 instances of inferior alveolar nerve paresthesia, 3 instances of trismus). All complications were transient; in one instance only of mandibular nerve paresthesia in group C symptoms were still present 25 months after the operation. DISCUSSION AND CONCLUSIONS: This study has shown no significant differences between group A and B, while complications significantly increase in group C. Recent researches have shown that: a) there is a low risk of development of pathologies correlated to third molar impaction; b) nowadays there are not valid criteria to evaluate the future eruption of the impacted tooth; c) a direct correlation between third molar impaction and anterior dental crowding hasn't been demonstrated yet; d) morbidity of the procedure is relevant. Therefore germectomy should be performed: a) if morphostructural alterations or ectopic impactions are present; b) in case eruption is not allowed for dysplastic alterations of the germs or pathological processes of the mandible; c) to gain space in the posterior segments of the lower jaw when distalization of first and second molars is necessary; d) in case of excessive anterior-posterior mandibular growth.

Adolescent↗
PubMed1994

Sinus lift and endosseous implants--preliminary surgical and prosthetic results.

The authors present their experience in 43 cases of maxillary sinus augmentation with autologous bone and hydroxylapatite granules via a lateral maxillary approach. During the same operation or after six months, according to width and height of the residual alveolar ridge, hydroxylapatite coated titanium endosteal implants (IMZ) were inserted in the maxilla; after an additional healing period of 6 months, dental prostheses were applied; the mean follow-up was 14.5 months (range: 12-24 months). Out of 124 implants inserted in the grafted sinuses, 8 failed, with a 93.5% success rate, whereas of 38 implants inserted in the grafted sinuses, 8 failed, with a 93.5% success rate, whereas of 38 implants inserted in the anterior maxilla, 2 (5.3%) failed. The results from this preliminary report indicate that composite bone grafting of the maxillary sinus is a very reliable technique that provides the bony structure for correct placement of endosseous implants.

Adult↗
PubMed1993

Side effects and complications associated with third molar surgery.

A retrospective analysis of complications and side effects associated with surgery for 1000 mandibular and 500 maxillary impacted third molars was performed. The analysis included 614 patients with impacted mandibular third molars and 274 with impacted maxillary third molars who were treated in a 5-year timeframe from 1987 to 1992. The incidence of intraoperative complications and side effects of mandibular third molar surgery was 1.1% and 4% for maxillary third molar surgery whereas postoperative complications were 4.3% and 1.2%, respectively.

Adolescent↗
PubMed1993

[Neurilemmoma (schwannoma) of the oral cavity. A report of 2 clinical cases].

Neurilemmoma (schwannoma) is a benign, encapsulated perineural tumor of neuroectodermal derivation that originates from the Schwann cells of the neural sheath of motor and sensitive peripheral nerves; the etiology is still unknown. The tumor is normally solitary, smooth-surfaced, slow growing and generally asymptomatic. It may develop at any age and there is no gender predilection. Head and neck are one of the most frequent localizations, but intraoral development is quite uncommon. In this area the mobile portion of the tongue, and in a decreasing order, the palate, the cheek mucosa, the lip and gingiva are the most frequent locations. Although it origins from the nervous tissue, only in 50% of the cases a direct relation with a nerve is demonstrated. The term schwannoma has been attributed in the past either for neurofibroma and neurilemmoma. Their histogenesis remain anyway a controversial argument. Some authors think that both tumors originate from Schwann cells and perineural connective cells. Others think that the first one originate from perineural cells, while the latter from Schwann cells. Diagnosis is confirmed by microscopic examination. Neurilemmoma shows two different components: Antoni type A and Antoni type B tissue. The first one consists of Schwann cells arranged in compact, twisted bundles, associated with delicate reticulin fibres and spindle-shaped nuclei aligned in parallel rows forming a typical palisading pattern. Between the rows there are fine cytoplasmatic fibrils with acellular, eosinophilic masses called Verocay bodies. The second one is formed by irregularly arranged masses of elongated cells and fibers similar in appearance to neurofibroma, with areas of cystic degeneration and edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Vital staining of oesophagus in patients with head and neck cancer: still a worthwhile procedure.

One hundred three patients with upper aerodigestive cancer were consecutively submitted to upper GI endoscopy with vital staining (Toluidine Blue 1%) of the oesophagus. The aim of the study was not only to confirm the prevalence of synchronous or metachronous tumour but also to verify the usefulness of the vital stain compared to simple endoscopy. Staining was positive in 29 patients (28.1%) for oesophagitis, leukoplakia, Barrett's oesophagus and 3 oesophageal neoplasms (2.9%), two of them unsuspected at endoscopy. We did not observe false positives while 13 cases (13/29-44.8%) were considered normal at endoscopy. Five cases with some endoscopic abnormality of the mucosa did not stain and were considered false negatives. Specificity of the method was 100%, sensibility 85.2%. The recognition of dysplastic changes and neoplasms not suspected at endoscopy should recommend in our opinion the use of vital staining of oesophagus in high-risk groups.

Adult↗