Implant supported single-tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions

Evaluation of aesthetics of implant-supported single-tooth replacements using different bone augmentation procedures: a prospective randomized clinical study

OBJECTIVES

The aim of this study was to evaluate the aesthetics of implant-supported single-tooth replacements using different augmentation procedures in a prospective study with the use of an objective rating index and with a subjective patient questionnaire, and to compare the results with each other.

MATERIAL AND METHODS

Ninety-three patients with a single-tooth gap in the anterior zone of the maxilla were selected for the study. All patients had a local bone defect that needed augmentation before placement of an endosseous implant with sufficient initial stability. Aesthetics of the implant-supported crown and adjacent mucosa was rated by a prosthodontist 1 year after placement of the porcelain crown. Aesthetics was rated using the Implant Crown Aesthetic Index. A subjective appreciation of the final result was assessed with a patient questionnaire.

RESULTS

The Implant Crown Aesthetic Index reveals a mean overall score of 4.8, with an acceptable result in 66% of the cases. Results of the satisfaction questionnaire reveal a mean overall score of 8.5 with an acceptable result in 100% of the cases. There is no correlation between results of the Index and the questionnaire for the overall and the crown score. The patients' opinion and the professionals' opinion about the peri-implant mucosa do show a significant correlation.

CONCLUSIONS

The peri-implant mucosa is rated as less satisfactory than the implant-supported crown by both the dental professional and patients. The dental professional was less satisfied with respect to the total result and results of the crown than the patients.

Optical phenomenon of peri-implant soft tissue. Part II. preferred implant neck color to improve soft tissue esthetics

OBJECTIVES

The purpose of this study was to investigate an optical solution to eliminate the undesirable shine-through effect of implants on peri-implant mucosa by selecting an optimized implant neck color based on an objective and quantifiable method.

MATERIAL AND METHODS

The optical effect of color strips on 15 peri-implant mucosal sites of 14 patients with Straumann single-tooth implant replacements in the maxillary anterior region was analyzed. The color differences between the peri-implant mucosa with insertion of each of eight different color strips (white, black, light pink, pink, light orange, orange, gold, violet) and the gingiva of an adjacent or contralateral tooth without any color strips were compared for the selection of optimal color of implant neck. Spectrophotometric color measurements were performed to compare the color difference index (DeltaE) and color coordinates (DeltaL*, Deltaa*, Deltab* and DeltaC*).

RESULTS

The colors of the peri-implant mucosa with color strips and the gingiva of natural tooth demonstrated that the test site soft tissue with color strips of light pink, pink, light orange and orange showed a significantly smaller DeltaE value (P<0.05). Moreover, light pink exhibited the lowest mean DeltaE value of 2.6+/-0.6, indicating a clinically indistinguishable color difference.

CONCLUSIONS

The results suggest that it is possible to improve gingival esthetics by coloring the implant neck, most effectively with light pink, to mask the impact of the underlying titanium implant. The use of implants with optimized neck colors to correct an esthetic deficiency may be a feasible approach to establish improved peri-implant soft tissue esthetics.

Optical phenomenon of peri-implant soft tissue. Part I. Spectrophotometric assessment of natural tooth gingiva and peri-implant mucosa

OBJECTIVES

The purpose of this study was to investigate the difference in optical appearance of the soft tissues labial to dental implants and to analyze the effects of titanium implant neck colors transmitted through the marginal mucosa.

MATERIALS AND METHODS

Fourteen patients with 15 Straumann single implant replacements in the maxillary anterior region were recruited. Color measurements of the peri-implant mucosa of test sites and the gingivae of contralateral or adjacent natural teeth as controls were made at the facial aspect of the teeth using a spectrophotometer. The color data (CIELAB color coordinates; L*, a*, b* and C*) in five incremental areas of 1 x 2 mm from the gingival margin toward the apical direction were obtained.

RESULTS

A significant difference existed (P<0.01) between the test site and the control site on the mean L* and b* values in all five incremental areas (area 1-5). In contrast, there was no significant difference in the mean a* values. Discrepancies between color distributions of soft tissues were stronger in areas close to the gingival margin and decreased toward the apical direction. The mean color difference DeltaE between the test site and the control site was 7.7 in area 1 and decreased toward area 5 with a value of 6.5. However, there was no statistical difference in each of the mean values of differences in optical data, DeltaL*, Deltaa* and Deltab*, when five incremental areas of the control and the test sites were compared.

CONCLUSION

It was observed that the color of soft tissue around the titanium implant was significantly different compared with the gingiva of natural teeth. Significantly lower values of CIELAB color coordinates, L* and b* were found in the peri-implant soft tissue.

Astra Tech single-tooth implants: an audit of patient satisfaction and soft tissue form

AIM

To investigate patient centred outcomes, soft tissue morphology, and bone levels.

MATERIAL AND METHODS

Sixty-six subjects, who had completed treatment for a single implant restoration at least l year previously. Appearance was recorded photographically and bone levels and interdental contact points measured from intra-oral radiographs using a x 7 scale loupe. Subjects completed a satisfaction questionnaire.

RESULTS

Subjects were highly satisfied with all aspects of the restoration including the appearance of the soft tissue (median shape/colour score 6 on scale 1-6). Twenty-eight sites in 20 subjects had no contact point between implant crown and adjacent tooth. A normal height papilla was judged to be present in 19 of these sites. These were excluded from the subsequent analysis. In the remaining 46 subjects with contact points the presence (JEMT score 3) or deficiency (score 1/2) of the papilla was significantly related to the distance to the bone level on the adjacent tooth and implant head. Differences were observed between the mesial and distal aspects of the implant restoration.

CONCLUSIONS

Examining clinicians were more critical of the restorations than the patients. The presence of a complete papilla was associated with a slightly greater distance from contact point to bone level than previously reported.

Effect of microthread on the maintenance of marginal bone level: a 3-year prospective study

OBJECTIVES

The purpose of the present study was to evaluate the long-term effect of the microthread on the maintenance of marginal bone level.

MATERIAL AND METHODS

Seventeen patients were selected and two types of Astra Tech implants were installed, with the Microthread on the coronal portion of the fixture [Astra Tech Single Tooth Implant (ST)] or without the Microthread [Astra Tech TiOblast Implant (TB)]. ST and TB were installed adjacent to each other within the same partially edentulous sites and marginal bone loss was evaluated by radiographic image. The marginal bone-level alteration of the each fixture after prosthesis insertion was analyzed.

RESULTS

The marginal bone loss of ST and TB differed significantly during the observation period (P<0.01). Marginal bone levels of both ST and TB were stabilized after 1 year of lading.

CONCLUSIONS

The Microthread might have an effect in maintaining the marginal bone loss against loading.

A review of the functional and esthetic requirements for dental implants

BACKGROUND

The esthetic replacement of teeth has become an important standard for implant dentistry. While defining this goal has not been difficult, the ability to restore implants esthetically has been fraught with obstacles and sometimes has not been attainable. The purpose of this review is to summarize essential anatomical and surgical considerations for cosmetic implant dentistry.

METHODS

This article provides a summary of the predominant findings from clinical studies and case reports that help develop implant surgical guidelines for better esthetic outcomes.

RESULTS

Soft- and hard-tissue requirements for placing an implant in an ideal position are defined. The authors discuss the best treatment approaches as well as the limitations associated with esthetic implant placement. They evaluate the available data specifically for the maxillary anterior sextant, since this anatomical region has higher esthetic demands.

CONCLUSIONS

Several parameters and various surgical techniques have been developed to manipulate soft- and hard-tissue contours and to control the esthetic outcome for implant-supported restorations.

CLINICAL IMPLICATIONS

It is essential for practitioners to understand the anatomical basis for and limitations of implant dentistry in the esthetic zone.

A 5-Year Prospective Study of Single-Tooth Replacements Supported by the Astra Tech® Implant: A Pilot Study

BACKGROUND

Implant-supported single-tooth replacements are an increasingly used method to replace teeth, especially in young patients. Therefore, long-term validation of different treatment modalities with different implant systems is of great importance.

PURPOSE

The aim of the present study was to make a biologic, technical, and aesthetic evaluation of single-tooth replacement supported by the Astra Tech implant (Astra Tech AB, Mölndal, Sweden) during a 5-year period.

MATERIALS AND METHODS

Twenty patients were divided into two consecutively treated groups. In group A the implants were placed "early" in the extraction sockets, and standard single-tooth abutments were used. In group B the implants were placed "delayed," and preparable abutments were used. Clinical examinations including registration of plaque, bleeding, crown lengths, soft tissue marginal level, papilla height, complications, and radiography were performed yearly. At the 3-year control examination the patient and a dentist evaluated aesthetic appearance with a visual analog scale.

RESULTS

An implant survival rate of 100% and a crown survival rate of 95% over a period of 5 years were found. The mean loss of marginal bone adjacent to implants and neighboring teeth was less than 0.5 mm during the 5-year period, and there was no significant difference after crown placement between the treatment modality for group A and that for B. There were fewer clinical complications and repairs in group B than in group A. Soft tissue dimensions were more natural around implant crowns in group B as compared to group A, but this was not reflected in the patients' satisfaction with aesthetic appearance. On the other hand the dentist judged the restorations in group B higher concerning aesthetics than in group A.

CONCLUSION

Implant-supported single-tooth replacement with the Astra Tech system is a reliable treatment resulting in a good 5-year prognosis and only few complications.

Tissue alterations at implant-supported single-tooth replacements: a 1-year prospective clinical study

OBJECTIVES

The aim of this prospective study was to evaluate dimensional alterations of the peri-implant tissues at single-tooth restorations from the time of implant placement to 1-year post-loading.

MATERIAL AND METHODS

Eleven patients, aged 18-36 years, subjected to single-tooth replacements with implant-supported restorations (Brånemark implant system) in the maxillary anterior region were included in the analysis. The implant installation was performed as a two-stage procedure with a 6-month healing interval. Bone dimensions were determined by direct assessments immediately following implant placement and at abutment connection. The prosthetic restoration was placed approximately 1 month after abutment surgery. Radiographic and clinical examinations were performed at crown placement and at 1-year post-loading. Assessments of the soft tissues at the implant site and at the neighboring teeth were performed before and during implant placement, before abutment connection, after crown placement and at the 1-year follow-up examination. Mean values and standard deviations were calculated for each variable and interval, with the subject as the statistical unit.

RESULTS

At the time of abutment connection, a mean loss of bone height at the facial and lingual aspect of the implant amounting to 0.7-1.3 mm (P < 0.05) was recorded, whereas no significant change was noted at proximal sites. A mean reduction of 0.4 mm of the labial bone thickness was observed between implant placement and the second-stage surgery. The radiographic bone-to-implant level showed a mean loss of 0.9 mm between abutment connection and crown placement (P<0.05) and a further 0.7 mm loss at 1 year (P < 0.05). The thickness of the labial mucosa was increased at crown placement followed by a slight remission at 1 year. During the corresponding interval, a mean apical displacement of the labial soft tissue margin of 0.6 mm had taken place (P < 0.05). A papilla fill of > or = 50% was observed at a frequency of 32% at crown placement and 86% at 1 year.

CONCLUSIONS

The results demonstrated that following implant surgery remodeling takes place, which is manifested in diminished bone dimensions, both horizontally and vertically, at the facial aspect of the implant. The observed soft tissue alterations after the crown placement may affect the esthetic appeal of the restorative therapy.

Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score

AIM

In this study, the reproducibility of a newly developed pink esthetic score (PES) for evaluating soft tissue around single-tooth implant crowns was assessed. The effect of observer specialization was another point of interest.

MATERIAL AND METHODS

Twenty observers (five prosthodontists, five oral surgeons, five orthodontists and five dental students) were given photographs of 30 single-tooth implant crowns. Seven variables were evaluated vs. a natural reference tooth: mesial papilla, distal papilla, soft-tissue level, soft-tissue contour, alveolar process deficiency, soft-tissue color and texture. Using a 0-1-2 scoring system, 0 being the lowest, 2 being the highest value, the maximum achievable PES was 14. Each observer was requested to make two assessments at an interval of 4 weeks. At the second assessment, the photographs were scored in the reverse order.

RESULTS

The mean PES of evaluations at the first assessment (n=600) was 9.46 (+/-3.81 SD), and 9.24 (+/-3.8 SD) at the second one. The difference between these two means was not significant statistically (P=0.6379). Implant-related mean PES for single-tooth implants varied from 2.28 to 13.8, with standard deviations between 0.46 and 3.51. Very poor and very esthetic restorations showed the smallest standard deviations. The mean total PES was 10.6 for the prosthodontists, 9.2 for the oral surgeons, 9.9 for the dental students and 7.6 for the orthodontists.

CONCLUSIONS

The PES reproducibly evaluates peri-implant soft tissue around single-tooth implants. Thus, an objective outcome of different surgical or prosthodontic protocols can be assessed. Orthodontists were clearly more critical than the other observers.

A new index for rating aesthetics of implant-supported single crowns and adjacent soft tissues - the Implant Crown Aesthetic Index

OBJECTIVES

The important item of aesthetics is rarely included in evaluation studies. The aim of this study was to develop and validate an index for rating aesthetics of implant-supported single crowns and adjacent soft tissues.

MATERIAL AND METHODS

Nine items were selected, which have an influence on the aesthetic result. The items are based on the anatomic form, colour and surface characteristics of the crown and on the anatomic form, colour and surface characteristics of the peri-implant soft tissues. Two oral-maxillofacial surgeons and two prosthodontists rated 24 implant-supported single-tooth restorations and adjacent soft tissues on a form with the nine items of the rating index. The rating was carried out twice by each of the examiners. Weighted Cohen's kappa was calculated to express the intra- and interobserver agreement.

RESULTS

Intraobserver results indicated that the agreement between the first and second rating of both the prosthodontists was good (both 0.7) and that the agreement of the oral-maxillofacial surgeons was moderate (0.49 and 0.56). The best interobserver agreement was found between the two prosthodontists (0.61, good agreement).

CONCLUSIONS

The Implant Crown Aesthetic Index is an objective tool in rating aesthetics of implant-supported single crowns and adjacent soft tissues. The rating is best be carried out by one prosthodontist to have the highest reliability.

Dimension of Keratinized Mucosa and the Interproximal Papilla Between Adjacent Implants

BACKGROUND

The interproximal papilla between two adjacent implants is gaining critical interest in the implant dentistry. The aims of this study were to evaluate the effect of 1) the width of keratinized mucosa, 2) the distance from the base of the contact point to the crestal bone, and 3) the horizontal distance between two implants on the radiographic dimension from the tip of the papilla to the crestal bone between two implants.

METHODS

This study involved 72 interproximal papillae between two adjacent implants (interimplant papilla) in 52 patients who had implants placed adjacent to each other and had a prosthesis in place more than 1 year. The shortest distance between the radiopaque material on the tip of the interimplant papilla and most coronal portion of the interimplant crestal bone was measured (the radiographic length of the papilla [RL]). The width of keratinized mucosa from the tip of the papilla was measured (WK). The vertical distance between the base of the contact point and the interimplant crestal bone was measured (CC). The horizontal distance between the two adjacent implants was measured at the fixture-abutment interface level (HD). Multiple regression analysis was performed between WK-RL, CC-RL, and HD-RL.

RESULTS

RL had a significant relation with WK between two adjacent implants (P = 0.001). However, RL was not related with other variables, such as CC and HD (CC, P = 0.641; HD, P = 0.901).

CONCLUSION

The results of this study suggest that the width of keratinized mucosa between two adjacent implants might be related to the dimension of the interproximal papilla between two adjacent implants.

Correlation of Papilla to Crestal Bone Levels Around Single Tooth Implants in Immediate or Delayed Crown Protocols

PURPOSE

The purposes of this study are to determine if there is a difference in the papilla fill between implant and teeth comparing immediate provisionalized and delayed single tooth implant restorations, and to determine the relationships between the vertical and horizontal bone levels to papilla filling the inter-dental region with single implant restorations.

PATIENTS AND METHODS

Two groups of patients treated with single tooth implant restorations were prospectively followed. One group had immediate provisionalization of their implants, and the second group a delayed approach. Serial radiographs and photographs were used to collect bone level measurements for the vertical distance between contact point to bone level on the adjacent tooth, implant, and the midcrestal region. The horizontal distances were also recorded. Papilla morphology was scored 1 through 4. Univariate analysis was used to evaluate the relationships between bone levels and papilla morphology.

RESULTS

There were no differences between papilla or bone levels comparing immediate provisionalization to delayed approaches. There were significant ( P < .05) relationships between the vertical distance from contact point to bone levels, with the distance from the contain point to the adjacent tooth the distance most critical to papilla maintenance. There were no significant relationships between horizontal distance and papilla maintenance.

CONCLUSION

As the distance from the contact point to the implant increased, there was a significant chance of loss of papilla. There was no difference between delayed or immediate provisionalization and papilla scores. The horizontal distance from adjacent tooth bone level did not correlate to papilla score within the range of clinically relevant distances.

Clinical and radiographic performance of delayed-immediate single-tooth implant placement associated with peri-implant bone defects. A 2-year prospective, controlled, randomized follow-up report

OBJECTIVES

The aim of the present study was to compare the delayed-immediate (Im) and the delayed (De) protocols for placement of single-tooth implants.

MATERIAL AND METHODS

After allocation to the Im and De groups by random, 46 patients were treated with a single-tooth implant with acid etched surfaces (Osseotite) in the anterior or pre-molar region of the maxilla or the mandible on average 10 days (Im) or 3 months (De) following tooth extraction, respectively. Forty-one patients attended a follow-up visit 2 years after implant placement corresponding to 1(1/2) years of loading of the implant restorations. Peri-implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs.

RESULTS

Three implants were lost, all before mounting of the crown. None of the implant restorations had failed after 1(1/2) years of function. Probing pocket depths were reduced by up to 1.4 mm on average from the time of loading to the 2-year follow-up and at that time, no significant difference between the Im and De groups was found (4.2 versus 4.1 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (mean=0.8 mm) as well as in the De group (mean=0.7 mm) in the follow-up period. However, a mean marginal bone level of approx. 1.5 mm in both groups measured from the implant-abutment junction was found to be acceptable. It was demonstrated that probing pocket depths and marginal bone levels after 1(1/2) years of loading of the implant-retained crowns were not influenced by the presence of peri-implant bone defects immediately after implant placement. Furthermore, no severe prosthodontic complications, such as screw loosening or porcelain fractures, arose in this study material.

CONCLUSION

High success rates of single-tooth implants after 1(1/2) years of function were achieved using the delayed-immediate and delayed implant placement techniques.

Patient experience of, and satisfaction with, delayed-immediate vs. delayed single-tooth implant placement

OBJECTIVES

Recent investigations have focused on patients' subjective assessment of implant treatment. The aim of this study was to compare the patients' experience of surgical and prosthetic procedures, as well as satisfaction with function and aesthetics following single-tooth replacements mounted to early vs. delayed placed dental implants.

MATERIAL AND METHODS

Forty-six patients were treated with a single-tooth implant in the anterior or premolar region. Twenty-three implants were placed on average 10 days after tooth extraction (Im), while 23 implants were placed approximately 3 months after tooth extraction (De). Forty-one patients completed a questionnaire regarding the treatment using visual analog scales (VAS) and check boxes 16-18 months after delivery of the restoration.

RESULTS

In all, 90% of the respondents rated 88 or higher on the VAS regarding satisfaction with the crown. Satisfaction with the restoration in general and the appearance was significantly greater in the Im group than in the De group (96 vs. 93; P<0.02). Assessment of the implant surgery was not significantly different between the delayed-immediate and the delayed group. Approximately 25% of the patients experienced unpleasantness in relation to the prosthetic procedures, and in 8 of 11 cases, impression taking was the cause. When evaluating satisfaction with the overall implant treatment, the VAS scores for the delayed-immediate group were significantly higher than for the delayed group (96 vs. 90; P<0.02).

CONCLUSION

The patients in the present study were highly satisfied with the outcome of the treatment and experienced it to be without significant unpleasantness irrespective of the treatment concept.

Peri-implant bone alterations in relation to inter-unit distances. A 3-year retrospective study

The aim of the present retrospective study was to evaluate longitudinal alterations in radiographic bone topography at proximal sites of three-unit implant-supported fixed partial prostheses during the first 3 years after bridge installation, in relation to vertical and horizontal inter-unit distances. The subjects were partially dentate patients who had received implant-supported fixed partial prostheses during the year 1995 at the Brånemark Clinic, Göteborg, Sweden. For inclusion in the study, the patient had to have a three-unit bridge construction supported by three implants in the posterior area of the jaw. Twenty-eight patients having 35 screw-retained prostheses on Brånemark standard implants fulfilled the inclusion criteria. Radiographs obtained at bridge installation and at 1- and 3-year follow-ups were assessed for implant positions, contact point level, bone level at implants and adjacent tooth and mid-proximal bone crest level. The data were analysed with respect to two proximal units: tooth/implant units (n=35) and implant/implant units (n=70). Multiple regression analyses were used to evaluate the influence of various factors on the peri-implant and periodontal bone level changes during the 3 years of follow-up. At the tooth/implant units, the mean bone loss over the 3 years was 0.5 mm at the implant and 0.4 mm at the tooth. Multiple regression analysis failed to identify significant explanatory factors for the peri-implant/periodontal bone level changes at the tooth/implant units (R2=0.28). At the implant/implant units, the peri-implant bone loss was 0.6-0.7 mm and was significantly influenced by the vertical inter-implant distance (P<0.01), the difference in bone level at baseline between two neighbouring implants (P<0.001) and the bone level changes at the opposed implant surface (P<0.001) (R2=0.49). Furthermore, the magnitude of apical displacement of the inter-implant bone crest level during the 3 years of follow-up was negatively associated with the horizontal inter-implant distance (P<0.05). The results of the study demonstrated that both vertical and horizontal differences in implant positions might influence bone alterations in the inter-implant area during the first 3 years of loading, while the data failed to show corresponding relationships for the bone changes at the proximal area between the implant and the neighbouring tooth.

Outcome of orthodontic space closure with a missing maxillary central incisor

Orthodontic space closure is one of the treatment alternatives when a maxillary central incisor is missing. Because no systematic analysis of such treatment results is available, a sample of 20 consecutively treated patients was examined in a follow-up study. All patients had received orthodontic treatment with the objective of closing the space for the missing central incisor. Biologic features and the clinical appearance of the recontoured lateral incisor (test tooth) replacing the missing tooth were compared with the neighboring intact central incisor, which served as control tooth. The patients' opinions regarding the treatment and the result were recorded in a questionnaire. The position of the examined teeth and the appearance of the surrounding soft tissues were similar in the test and control teeth. However, in some patients (25%), certain aspects of the recontoured incisor crown (such as the width at the gingival margin) mismatched the appearance of the controls. A somewhat increased mobility and probing pocket depth on the mesial aspect was recorded for some test teeth. No obvious detrimental effects were observed on the radiographs. Most patients expressed satisfaction with the treatment result. It is concluded that orthodontic mesialization of the lateral incisor to replace a missing central incisor is a valid treatment modality, if the indications for such treatment are present and careful attention to detail in orthodontic and restorative treatment is exercised.

Laminin-5 gamma2-chain and collagenase-2 (MMP-8) in human peri-implant sulcular fluid

Laminin-5 (LN-5) is an important epithelial cell-derived structural and adhesive component in hemidesmosomes and basement membranes (BM). In peri-implant tissue, gingival BM underlies the junctional epithelium (JE) and reflects the peri-implant health. Matrix metalloproteinase-8 (MMP-8 or collagenase-2) is one of the key mediators of periodontal tissue destruction. Western immunoblotting with image analysis was used to quantitate the molecular forms of LN-5 gamma2-chain and MMP-8 in peri-implant sulcular fluid (PISF) from healthy and diseased implants. These observations were related to the recorded gingival (GI) and bone resorption (BR) indices of the studied sites. Altogether, 72 PISF samples from osseointegrated dental implants were examined. Significantly elevated levels of fragmented LN-5 gamma2-chain species (45 and 70 kDa) and MMP-8 immunoreactivities were observed in diseased PISF in relation to healthy PISF. The elevated levels of both LN-5 gamma2-chain 45 and 70 kDa fragments and MMP-8 in diseased PISF from peri-mucositis (BR = 0) and peri-implantitis (BR >/= 1) lesions strongly correlated with elevated GI. Low levels - almost comparable to those seen in healthy control PISF - were seen in PISF from peri-implantitis lesions (BR >/= 1) with no GI. Activation of 75 kDa neutrophil (PMN)-type proMMP-8 to 10 kDa lower-molecular-size active forms was especially detected in PISF from peri-implantitis with elevated GI. These cross-sectional findings indicate that elevated MMP-8 and LN-5 gamma2-chain fragment levels in PISF can reflect the active phase of the inflammatory peri-implant disease. Longitudinal studies are required to assess their use, either alone or in combination as molecular biochemical PISF markers, to predict the risk of progression of peri-implantitis, as well as to monitor the impact of treatment of the disease.

Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans

BACKGROUND

Attempts have been made to evaluate the biologic dimension of osseointegrated implants, however, most are histologic studies in animals, and the effect of soft tissue support from adjacent teeth on the interproximal dimension of the peri-implant mucosa for anterior single implants has not been addressed. This study clinically evaluated the dimensions of the peri-implant mucosa around 2-stage maxillary anterior single implants in humans after 1 year of function. The influence of the peri-implant biotype was also examined.

METHODS

Forty-five patients (20 males and 25 females) with a mean age of 47.3 years were included in this study. A total of 45 maxillary anterior single implant crowns with a mean functional time of 32.5 months (range, 12 to 78) were evaluated. The dimensions of peri-implant mucosa were measured by bone sounding using a periodontal probe at the mesial (MI), mid-facial (F), and distal (DI) aspects of the implant restoration and the proximal aspects (MT, DT) of adjacent natural teeth. In addition, the peri-implant biotype was evaluated and categorized as thick or thin. Statistical analysis was performed using an independent t test (P<0.05).

RESULTS

The means and standard deviations of the dimensions of peri-implant mucosa at MT, MI, F, DI, and DT were 4.20 +/- 0.77 mm, 6.17 +/- 1.27 mm, 3.63 +/- 0.91 mm, 5.93 +/- 1.21 mm, and 4.20 +/- 0.64 mm, respectively. The dimensions of peri-implant mucosa in the thick biotype were significantly greater than the thin biotype at MT, MI, and DT (P<0.05).

CONCLUSIONS

The mean facial dimension of peri-implant mucosa of 2-stage implants is slightly greater than the average dimension of the dentogingival complex. The level of the interproximal papilla of the implant is independent of the proximal bone level next to the implant, but is related to the interproximal bone level next to the adjacent teeth. Greater peri-implant mucosal dimensions were noted in the presence of a thick peri-implant biotype as compared to a thin biotype.

Patient satisfaction and quality of single-tooth restorations

This retrospective study focuses on patient opinion and professionally assessed quality of single-tooth restorations of Brånemark fixtures. Patients were treated by periodontists for fixture installation and/or abutment connection and by referring general practitioners for prosthetic rehabilitation. Seventy-eight consecutively treated patients were sent a questionnaire regarding aesthetics, phonetics and overall satisfaction. Forty-eight patients (52 fixtures) returned the questionnaire. Forty were able to attend a clinical examination by an independent examiner. The quality of 43 single implant crowns was evaluated according to the modified guidelines for assessment of quality and professional performance used for evaluation of design, fit, occlusion/articulation and aesthetics. Bone to implant level was assessed radiographically. Patients were very positive about aesthetics, phonetics, eating comfort and overall satisfaction. Nevertheless, 6/40 patients would not undergo the same treatment again, yet all of them would recommend it to others. The professionally rated quality of the crowns was perfect in 17 and acceptable in 25 cases. One crown needed modification to prevent future complications. Two crowns had already been replaced as a result of porcelain fracture; one restoration showed abrasion and one was damaged. With a mean loading time of 33 months (range: 3-89 months), none of the patients returning the questionnaire had encountered fixture loss. All except five fixtures showed bone remodelling at or above the first implant thread. It is concluded that single Brånemark fixtures installed by periodontists and restored by general practitioners are of an acceptable clinical quality to satisfy the patient.

The esthetic outcome of autotransplanted premolars replacing maxillary incisors

Autotransplantation of developing premolars to replace maxillary incisors has been documented to provide physiologically sound results, but comprehensive studies of the esthetic outcome have not been made previously. In order to assess the applicability of this approach and to identify factors important for planning of treatment, 22 autotransplanted premolars reshaped to incisor morphology were compared to their natural, contralateral maxillary incisors by scoring of features considered important for esthetics (color, soft tissue appearance, tooth morphology, and position). The sum of scores for each feature was used to place the reshaped transplant in one of three categories - Match, Deviate, Mismatch. The 22 patients were asked to fill in a questionnaire which addressed the same features that were examined professionally, and the responses were categorized as either Satisfied, Acceptable, or Dissatisfied. Eleven of the 22 patients had received orthodontic treatment with fixed appliances following the transplantation. Most of the transplanted premolars matched the contralateral incisor, and the majority of patients were satisfied with the appearance of the transplant. Fourteen percentage of the transplants were categorized as Mismatch and 18% of patients reported dissatisfaction. The distribution in categories assessed professionally and by the patients was not significantly different. The color and gingival width of the transplanted tooth were scored as different from the natural incisor in about half of the bilateral comparisons. For those teeth categorized professionally as Mismatch and by patients as Dissatisfied, a potential for esthetic improvement could be identified, as allocation to these categories was primarily due to suboptimal positioning and restorative build-up of the transplant. Inter-disciplinary planning is important for successful esthetic results.

Long-Term Changes in Soft Tissue Height on the Facial Surface of Dental Implants

The success of osseous healing around dental implants has allowed for an increased emphasis on soft tissue healing and esthetic results. However, there is limited information profiling the long-term healing of the soft tissues following prosthesis placement. The purpose of this study was to assess the long-term changes in the position of the facial soft tissue margins following restoration of a one-stage implant system. One hundred and six one-stage ITI implants were evaluated in 39 patients. Implants were placed in maxillary and mandibular anterior regions. Clinical assessment of the soft tissues on the midfacial aspect of the implants was performed over a 2-year period, at 3 and 6 month intervals, following placement of the final restoration. A total of 63 implants were placed as multiple units in the mandible, 23 as single units in the maxilla, and 20 as multiple units in the maxilla. There were no implant failures over this time period. Overall, on the facial aspect of 61% of the 106 implants there was 1 mm or more of soft tissue recession, whereas 19% of the implants showed 1 mm or more of gain in soft tissue height. There was a significantly (P < 0.01) greater number of implants showing a gain in soft tissue levels in the mandibular implants compared with the maxillary implants. Of the 39 patients assessed, 24 showed a loss and five showed a gain of 1 mm or more of the soft tissue levels around the implants. Overall, there was a significant decrease in the mean levels of tissue height of 0.6 mm within the first 6 months, with relatively little change afterward. However, in evaluating only patients showing a loss in tissue height around one or more implants, the mean loss in tissue height was 1.6 mm after 24 months. These results suggest that the potential for significant changes in soft tissue levels after completion of restorative therapy need to be considered for implant therapy in esthetic areas.