Oral rehabilitation of tooth agenesis frequently starts in paediatric dentistry. A retrospective analysis of 625 patients.

AIM: As oral rehabilitation of tooth agenesis usually begins at a very young age, it is important to plan the therapy in advance in order to prepare the patient for the final treatment after the end of skeletal and dental growth. The diverse patterns of tooth agenesis require interdisciplinary oral rehabilitation adapted to individual factors like patient's age, number of missing teeth, and alveolar-bone development. The aim of the present high volume single-center study was to provide an overview of the management of patients with tooth agenesis, in terms of treatment approaches, associations, and long-term implant survival, over a period of 30 years. METHODS: Descriptive analyses were performed to analyse treatment approaches and and how they reated to severity of agenesis as well as patients' gender and age. Kaplan-Meier survival curves and log-rank-tests were used to investigate implant survival over time. CONCLUSION: Treatment starts usually in childhood or adolescence; orthodontic therapy was the most common treatment. All treatment options showed similar high survival rates. External bone augmentation might be a risk-factor for implant loss.

Atrophy of the residual alveolar ridge following tooth loss in an historical population.

OBJECTIVES: To study the natural aetiopathology of jaw atrophy after tooth loss, unaltered by prosthetic procedures, an historical population without modern dental treatment was examined. METHODS: Based on the hypothesis that there are predictable changes in shape during jaw-atrophy, frequency and degree of atrophy as well as clinical aspects of bone quality and resorption were determined in the skeletal remains of 263 individuals. The potential association between age and frequency/severity of atrophy was analysed. RESULTS: Atrophy in at least one jaw segment was present in 45.2% of the analysed jaw specimens. The residual ridge underwent a series of changes in shape and height following the pattern of resorption described for modern populations. The severity of these alterations was associated with the age of the individual and the region within the jaw. Atrophy was frequently related to structural degradation of the covering cortical layer. CONCLUSIONS: These findings prove that atrophy of the jaw evidently does occur, displaying similar patterns of resorption in a population without modern prosthetics, where the negative effect of ill-fitting dentures is excluded. The basic information about alterations of shape and the cortical layer covering the residual crest might help to provide a deeper insight into aetiopathological mechanisms of this common oral disease.

Characteristic features of trabecular bone in edentulous mandibles.

BACKGROUND: The density and architecture of the alveolar trabecular bone are crucial to the stability of an endosseous implant. A significantly higher implant failure rate can be expected when implants are placed in alveolar bone with reduced density and stability. Therefore, the present study aimed to describe the trabecular bone structure of edentulous mandibles. METHOD: Two hundred and seventy-eight bone sections, including the lateral incisor, first premolar, and first molar regions, were obtained from 128 edentulous lower jaws (68 females and 60 males; mean age: 77.58 years). Ground sections were prepared for each region using the 'sawing and grinding' technique. The following standard structural histomorphometric parameters were determined using a semiautomatic image analysis: trabecular bone volume, trabecular thickness, trabecular number, trabecular separation, and the trabecular bone pattern factor, which describes the connectedness of cancellous bone structures. Also, the maximum height of the jaw section was determined, to detect any possible correlations between vertical height and histomorphometric parameters. RESULTS: All the histomorphometric parameters examined showed an unexpectedly huge range of variation. The mean trabecular bone volume ranged between 20.9% and 36.9%. The mean trabecular thickness showed values between 165.9 and 224.7 microm. The mean trabecular number ranged between 1.22 and 1.77/ mm, and the mean trabecular separation ranged between 436.7 and 720.0 microm. The mean trabecular bone pattern factor showed values between -0.05 and -3.01/ mm. The maximum height of the jaw sections showed values between 16.05 and 23.42 mm. The trabecular bone volume, thickness, number and connectivity were significantly lower in the molar region than in the incisal and premolar regions. Significant sex-specific differences were found in all the regions, female mandibles showing a smaller amount and lower connectivity of cancellous bone than male mandibles. No correlation could be found between the maximum height of the jaw and the histomorphometric parameters of the cancellous bone. CONCLUSION: A possible explanation for the difference in the density between the incisal and the molar region may be that molars are generally lost at an earlier age than anterior and premolar teeth. As a result, atrophy-related resorptive and remodeling processes commence earlier and progress further in this region than in the anterior and premolar regions. Sex-specific differences are probably due to an increased postmenopausal bone loss of the females.

Lip piercing: prevalence of associated gingival recession and contributing factors. A cross-sectional study.

BACKGROUND AND OBJECTIVE: Body piercings have increased tremendously in popularity in recent years. For oral piercing, late complications include gingival trauma and localized periodontitis. The purpose of this cross-sectional study was to investigate the prevalence and contributing factors of gingival recession associated with labial piercing. MATERIAL AND METHODS: The test group included 50 subjects with lower-lip studs. Nonpierced controls were matched according to gender, age and smoking status. Clinical examination included plaque and bleeding indices, probing depth, recession, clinical attachment level, width of keratinized gingiva, periodontal biotype, insertion of frenula, evaluation of hard tissues, trauma of occlusion, characteristics of the stud, radiographs and photographs. RESULTS: Gingival recessions were noted on teeth opposite the stud in 68% of the test group compared with 4% of the controls. Localized periodontitis was recorded in 4% of test subjects. Time since piercing and the position of the stud in relation to the cemento-enamel junction were significantly associated with the prevalence of buccal recessions. There were no significant associations between piercing and abnormal tooth wear. CONCLUSION: The prevalence of gingival recessions is associated with labial piercing. The position of the intra-oral disc and time since piercing are associated with a greater prevalence of gingival recession. A narrow width of keratinized gingiva is associated with increased buccal recessions.

The symphyseal single-tooth implant for anchorage of a mandibular complete denture in geriatric patients: a clinical report.

Little information exists to define the minimum number of implants required for sufficient anchorage of mandibular overdentures. To date, 2 implants placed in the interforaminal region have been considered the minimum. The aim of this study was to examine whether a single symphyseal implant would suffice for adequate anchorage of a mandibular complete denture in elderly patients (octogenarians), and whether this surgically, prosthetically, and financially simple concept would also satisfy patients needing replacement of the mandibular dentition. Nine patients with a mean age of 82.2 years underwent placement of a single symphyseal endosseous implant and anchorage of a complete denture using a ball attachment. Standardized recall examinations, including patient response and inspections of the peri-implant soft tissue and bone conditions, were carried out at 3- to 6-month intervals for a period of 1 1/2 years. It was found that anchorage with a single implant led to both a significant improvement in patients' subjective satisfaction (P < .01) and a significant reduction in reported symptoms (P < .01). During the observation phase, pocket depth and bone resorption initially increased around implants but stabilized after the sixth month. Denture management (placement and removal) also improved during the recall period (P < .01). The results of this study indicate that oral rehabilitation by mandibular complete dentures anchored on a single implant can be considered an economical therapeutic alternative to a conventional mandibular complete denture for very old (octogenarian) patients.

Computed tomographic diagnosis and localization of bone canals in the mandibular interforaminal region for prevention of bleeding complications during implant surgery.

In this study, computed tomograms (CTs) of 70 patients were examined for visible vascular canals in the mandible as well as for their localization, incidence, diameter, and content. All patients examined showed at least 1 lingual perforating bone canal in the mandible. Since such vascular canals are encountered regularly, routine CT examination is recommended prior to implant surgery to help avoid severe bleeding complications during the placement of implants in the interforaminal region.

Effects of reduced mouth opening capacity (trismus) on pulmonary function.

In this study, pulmonary function test data were obtained from 15 healthy volunteers and 15 patients with slightly impaired ventilation during both normal and maximally reduced opening of the mouth (trismus, intercuspal position). The aim of the study was to examine the effects of complete trismus on pulmonary function using objective and subjective parameters. In maximally reduced mouth opening, both groups showed an impairment of all subjective and objective pulmonary function test data. In healthy volunteers, the significant changes in test data (P<0.05) stimulated mild to moderate pulmonary impairment, whereas patients with an already impaired pulmonary function showed a marked deterioration of their initial respiratory condition. The results of the subjective and objective parameters examined indicate that an intercuspal position (trismus) further aggravates pulmonary functional impairment. Complete trismus can be considered a risk factor to pulmonary function in patients using mouth breathing as a primary or supportive mode of respiration.

Assessment of the blood supply to the mental region for reduction of bleeding complications during implant surgery in the interforaminal region.

Several life-threatening complications caused by hemorrhage that can occur during the placement of dental implants in the mandibular interforaminal region have been described in the literature. The aim of this study was to assess the vascular supply to this region and delineate the relative contribution and importance of the sublingual artery versus the submental artery. Thirty-four human cadavers were dissected. Special attention was directed to the presence of a branch of the submental artery that perforates the mylohyoid muscle and thus participates in the blood supply to the floor of the mouth together with the sublingual artery. A sublingual artery was found in 71% of the specimens. A large branch of the submental artery perforating the mylohyoid muscle was found in 41% of the specimens. The point of perforation was located an average of 31 mm posterior to the menton. The high risk of injuring the vessels of the floor of the mouth can be explained by the close vicinity of these vessels to the mandibular lingual cortical plate. To prevent complications in cases of unclear anatomic identification of the fossa sublingualis, preoperative lingual probing or elevation of the periosteum of the lingual aspect of the mandible is necessary. An alternative diagnostic procedure is precise preoperative noninvasive imaging (eg, computed tomography).

Use of crestal bone for augmentation of extremely knife-edged alveolar ridges prior to implant placement: report of 3 cases.

A technique is presented for interforaminal lateral augmentation of mandibles with adequate bone height, but extremely knife-edged mandibular alveolar ridges (Class IV of Cawood and Howell's classification of residual ridges), in which the crestal portion of the knife-edged ridge is used as grafting material. Following an osteotomy and rotation of the grafts by 180 degrees, the grafts were fixed to the residual ridge below the osteotomy line by means of miniscrews. All grafts showed only mild resorption after a healing period of 3 months, and it was possible to place 4 implants in the now sufficiently wide host region.

The incidence, location, and height of maxillary sinus septa in the edentulous and dentate maxilla.

PURPOSE: This study evaluated the incidence, location, and height of antral septa and demonstrates their clinical implications. MATERIALS AND METHODS: One hundred ninety-four maxillary posterior regions, subdivided into four groups (group 1, 61 clinically examined atrophic ridges; group 2, 41 anatomically examined atrophic ridges; group 3, 42 radiographically [CT] examined atrophic ridges; and group 4, 50 CT examined dentate maxillary ridges), were examined for the incidence, location, and height of antral septa. RESULTS: The incidence of antral septa was significantly greater (P<.01) in atrophic edentulous regions (groups 1, 2, and 3) than in dentate regions (group 4). However, the septa were much lower (P<.01). In atrophic maxillae, about 70% of antral septa were located in the anterior (premolar) region. CONCLUSIONS: Antral septa are more commonly found in edentulous atrophic maxillae than in dentate maxillae. The septae in edentulous atrophic maxillae are shorter than those found in dentate maxillae. When present, maxillary sinus septae are more common anteriorly than posteriorly. CT scanning is the preferred radiographic method for detecting the presence (or absence) of sinus septae. Panoramic radiography has less sensitivity and specificity than CT scanning for the detection of sinus septa.

Blood supply to the maxillary sinus relevant to sinus floor elevation procedures.

The maxillary blood supply is essential for preserving the vitality of the affected maxillary region, integration of the grafting material, and wound healing such as following sinus floor elevation. Although it is well established that edentulous maxillae demonstrate a decreasing vascularity as bone resorption progresses, the vascular conditions relevant to sinus floor elevation procedures have not been investigated yet. This study deals with maxillary arteries relevant to sinus floor elevation surgery and examines the vascularization of the lateral maxilla after tooth loss. The vessels of the lateral maxilla of 18 maxillary specimens (10 male, 8 female, mean age 67 years) were prepared anatomically and the local main arteries, the number of macroscopically discernible branches and anastomoses, their calibers, and the distance between the caudal main branches and the alveolar ridge recorded. The lateral maxilla is supplied by branches of the posterior superior alveolar artery (PSAA) and the infraorbital artery (IOA) that form an anastomosis in the bony lateral antral wall, which also supplies the Schneiderian membrane. This intraosseous anastomosis was found in all of the specimens. Eight of 18 also showed an extraosseous anastomosis between PSAA and IOA, vestibular to the antral wall, giving off an average of 3 branches cranially and 5 branches caudally. The two anastomoses form a double arterial arcade to supply the lateral antral wall and, partly, the alveolar process. The PSAA had a mean caliber of 1.6 mm and exhibited an average of 2 endosseous and 1 extraosseous branches. The IOA had a mean diameter of 1.6 mm and showed an average of 1 endosseous and 3 extraosseous branches. The mean distance between the intraosseous anastomosis and the alveolar ridge was 19 mm in 2 defined measuring sites. Its mean length was 44.6 mm. The epiperiosteal vestibular anastomosis was situated further cranially at a mean distance of 23 to 26 mm from the alveolar ridge and had a mean length of 46 mm. The rather large caliber of the vessels supplying the lateral antral wall seems to be crucial to the fact that the periosteal blood supply is maintained even in severe maxillary atrophy and after complete disappearance of the centro-medullary vessels.

Characteristic features of trabecular bone in edentulous maxillae.

Following tooth loss, the maxillary alveolar ridge is affected by extensive resorption and its cancellous bone substance undergoes intense remodeling processes. This is particularly important for endosseous implant surgery as the primary stability and thus the prognosis of endosseous implants depends on the cancellous bone density and structure of the alveolar ridge. To analyze the structure of alveolar trabecular bone, 156 sections were obtained from 52 edentulous maxillae (29 female, 23 male; mean age: 72.5 years) from the lateral incisor, first premolar, and first molar regions. The structural histomorphometric analysis was performed on cancellous bone of the section surfaces using semiautomatic image analysis. The following parameters were measured: trabecular bone volume, trabecular number, trabecular thickness, trabecular plate separation and trabecular interconnection. All examined parameters showed an extreme range of variation. A difference of more than 45% between the highest (= 51.93%) and the lowest (= 6.73%) trabecular bone volumes was found. Furthermore, the measurements showed that trabecular bone volume, thickness and number were distinctly lower in the molar region than in the incisal and premolar regions. Significant sex-specific differences were found in all investigated regions, female maxillae showing a smaller amount and a lower connectivity of cancellous bone than male maxillae.

Treatment of patients with extreme maxillary atrophy using sinus floor augmentation and implants: preliminary results.

Twenty consecutive patients with extreme maxillary atrophy underwent bilateral sinus floor augmentation, either with autogenous bone from the iliac crest or with a combination of autogenous bone and hydroxyapatite. One patient was treated using autogenous bone from the chin region. After a period of three to eight months, three to four implants were placed in each posterior maxilla. Only 10 out of 155 inserted implants were located in the anterior non-augmented maxilla. During the observation period of one to six years, four implants (one of them located in the anterior maxilla) had to be removed prior to prosthetic treatment. Another three implants were lost during the follow up period. This corresponds to a Kaplan-Meier survival probability of 95.4% after 70 months. No statistically significant difference in implant success was observed between women and men (P=0.16). All prosthetic suprastructures are still in function despite these implant losses. Mean peri-implant bone resorption was 1.34 mm with no statistically significant difference between implants placed more mesially and those placed more distally in the augmented area, though a trend could be observed (P=0.058) for a more pronounced bone resorption around implants placed in the premolar region. When a mean mesial and distal bone resorption of >2 mm was considered in the calculation of the success prognosis, the survival probability dropped to 74.7% after 70 months.

Maxillary sinus septa: incidence, morphology and clinical implications.

This study was carried out to examine the incidence, morphology and clinical implication of antral septa. Out of 265 maxillary sinuses, 65 sinuses in atrophic maxillae were examined clinically during sinus floor elevation and 200 sinuses examined radiographically (CT), the latter being further subdivided into non-atrophic/dentate and atrophic/edentulous maxillary segments. Eighteen (27.7%) out of 65 clinically-examined maxillae and 32 (16%) out of the 200 non-preselected CT-examined maxillary sinuses showed antral septa. CT-topogram subclassification revealed 21 septa (13.2%) in 159 non-atrophic and 11 septa (26.8%) in 41 atrophic maxillary segments (P < 0.01). Morphologically, CT examination yielded one complete septum (0.5%), 21 incomplete septa on the sinus floor and 10 incomplete septa on the anterior antral wall (5%). CT revealed a significantly greater dimension of antral septa in non-atrophic maxillary segments than in atrophic ones (P < 0.01). In atrophic maxillary sinuses, the incidence (27.7% vs 26.8%), morphology (all septa located on sinus floor) and height (8.1 +/- 2.5 mm vs 6.8 +/- 1.6 mm) did not differ between the clinical and the CT examinations. Detailed knowledge about location, morphology and height of antral septa is clinically relevant to reduce the rate of complications when maxillary sinus surgery, i.e. sinus floor elevation, is carried out.

Complications of sinus perforations and their management in endodontics.

The intimate position of the maxillary sinus to the apices of teeth creates problems if periapical inflammation occurs. This can lead to a perforation into the sinus and cause sinusitis. Persistent and complicated situations that do not respond after nonsurgical root canal treatment demand a suitable surgical therapy. Knowledge of the specific anatomic conditions, an adequate diagnosis, and an appropriate surgical procedure facilitate success rates that are comparable with those obtained in other regions, even in unfavorable initial conditions.